The reason you are seeing the voltage changing between the to hot legs is the two inverters are not running at EXACTLY 60 hz....so their phase is not synchronized. What is happening is as the inverters come into phase with each other you will see 0 volts. And the voltage will rise as they go out of phase until they reach 180 degrees our of phase, showing you a peak voltage, approx 240v. You can tell exactly how many cycles apart they are by timing the how long it takes from peak to peak. This is how power generation plants sync with the grid before closing their interconnect with the grid. They monitor the voltage between the interconnect and their generator. They adjust the RPM so the cycles are VERY close. Then they wait for the zero crossings match and close the circuit. You can do the same thing with multiple generators connected to your home at the same time.
@@Icehso140 Do you know which brands do this? When I was looking for two 3k inverters to do that, all I could find were parallel kits that sync'd to be in phase, providing more amps but at 120 volts. I could not find any that would sync 180 out of phase to produced 240v.
100% correct and well explained. An interesting case is that once the generator is synched and connected to the grid, it is very difficult to get it out of sync or out of phase because the grid will resist those changes.
The drifting phases assumptions are correct. Some inverters are equipped to automatically synchronize as a cooperating pair, providing center-tap style 120v/240v. I have a pair of Xantrex 2 kw inverters, new in 2007, that are configured so. They work flawlessly, including auto cut-over, auto phase synchronization, with an absolutely perfect waveform. The inverter pair easily power the 120v and 240 loads including the range-top, oven, HVAC (A/C, furnace blower, etc.), at 4 kw continuous, 6 kw peak/surge. Each inverter is also a 100 amp, fully computerized battery charger keeping my bank of golf-cart batteries in tip-top condition. The cascading power sources are mains, solar, and finally propane fueled generator. When the mains fail, the generator, solar panels, or batteries power the inverters which are always carrying the load.
I think the two separate battery banks are drifting in and out of phase with each other since their inverters are not electronically synced to each other in any way.
Edited with more info: There are two reasons for the 240 volt problem. Number one as you mentioned the frequencies are probably not exactly the same. However, the second problem is that they are also not going to be in phase with each other. Even if they were both electronically synced to be exactly the same frequency, it's unlikely they would be in phase with each other. If they WERE synced to be the exact same frequency but NOT synced to be in phase, you would see some STEADY voltage between 0 and 240 depending on the phase difference. In any case, if you were to look at a graph of the two 120V sine waves above each other WITH ONE INVERTED, the voltage at any moment in time would be the sum of the 2 voltages at that point in time. (Or on the graph, if the sine wave displays are touching each other, it would be the voltage equivalent to the distance between the two points at that moment.) Another way to think of it is that the voltage on the 240 connection is the sum of the instantaneous voltage of the two sources at any point in time. Please keep in mind that the instantaneous voltage can be positive or negative at any moment in time. (I don't want to complicate things but for those that might try to point this out, yes the meter probably measures RMS, and the graphs would show peak which can go much higher than 240, but the basic principle is there.) I apologize if anyone else said the same thing but I haven't read all comments. An interesting experiment. I enjoy your channel.
on the bright side, it was much better that you discovered that the breaker was faulty outside a real power outage or an emergency, which is why we must periodically test all power systems, especially those that are infrequently used. Cheers from Brazil.
You nailed it… the frequency between the two separate power sources are not synchronized. One is probably running at something like 58hz. 😂and the other at 63hz. So there sine waves were sometimes in opposition and other times they were in parallel thus cancellation.
Exactly. They're probably both at 60 hertz but not exactly and the phase shift allows them to be in sync and then out of sync causing the voltage differences over time.
You have frequency and shift between the two frequencies based on time. The 240 voltage is based on the shift in the frequencies not the frequency itself.
I find the thinking process to be real cool. With all the new tech coming out this puts some new ideas in the air. thanks for demonstrating this to all of us.
The varying LED is an example of what in physics is called 'beats". You can hear the same thing happen when you have two different tones play that are slightly different frequencies. With the beat frequency you can measure the difference in frequency between the two sources So if one is 59hz and the other is 60hz, you'd hear a beat frequency of 1hz. Yours looked like a frequency of about 8-10 seconds, so you'd expect a difference between the two of something like .1hz. For example, one might be 59.8hz and the other is 59.9 hz.
You should also turn off any multiwire branch circuits, since these circuits share a neutral. (Which of course should have a shared breaker). I'm not really sure what would happen with these circuits since they share a neutral, but at the very least you'd be out of code since they no longer will balance any load between the two phases, since as you observed they aren't.
The US National Electric Code (NEC) 2020 edition requires that all Multi Wire Branch circuits (MWBC)s have one of two arrangements of the circuit breaker/s supplying them. Either handle ties or a double pole breaker. If it's a 2 pole breaker that would take care of the neutral overloading issue of MWBCs when you threw all of the double pole breakers to off with the caveat that the requirement for special control of MWBCs is relatively recent and it is unlikely that any but rather recent panels have been upgraded to comply with this new requirement. If handle ties are used then you would have to treat all of the handle tied breakers the same as double pole breakers and turn those off as well. Tom Horne
Similar to a 120v generator feeding both panel legs with 240v breakers off. Best to use single breakers protecting eack leg separately. If one leg goes over current, only one leg will drop out. Great video proof it can be done safely.
It depends. If you develop software, it’s a hardware problem. If you maintain hardware, it’s a software problem. If these two fail then it’s a network problem. Network guys: we didn’t make any changes. (Oh, wow, how many times have heard that.)
That weird voltage you are seeing across the 240V is the 2 power sources are out of phase with each outher .If you you have a dual trace scope you can see the two wave forms and you can see they both do not line up. On the larger power banks there is a sync cable to go between them and that will fix that 240V problem. Also some generators have a sync cable as well . like the larger Honda inverter generator . also can put 2 120V loads together for more amps. I made a cord like you use in video but used 10/3 wire for the 2 legs and 20A 120V plug. I have gen set that output 20 amps 120V + . also both 120V plugs can be put into same source .being 180deg out of phase there will be 0 volts between the 2 hot legs. is ok to do this ,same again 240V loads turn off. I have been a electrician in Boston NY over 30 years now and had my share of bugs getting inside panel box and breakers. I keep bee and bug spray on hand. Them little things can find a way in. nice video. 😀
Southwest Missouri here, it was an interesting experiment. Really liked it. As others have mentioned using actual generators would be another interesting scenario thanks for the video
Awesome video. I have been thinking along these lines as well. I have 24 250W solar panels. 12 go to one solar charge controller/inverter and 12 go to another. Each of these have their own 10KW battery bank. They each put out 120v. If I connected them together and connected a data cable between them I could configure the inverters to output 240V but the 2 units have to be on a shared battery bank. And my lithium battery banks are identical in configuration (4 12V 200AH) but each bank of 4 batteries are of a different manufacturer. Also I had read a data sheet from one of the manufacturers to not exceed 4 batteries in one bank. So, I have been hesitant to run my two inverters in sync with each other to get the 240v and sidelining a perfectly good bank of 10KW. So this has been on my mind a lot lately. Thanks for the additional thought material!
Need to have two of the same brand/size generators and have a sync option otherwise they will be out of phase. I think there might be a problem with 2 120 volt circuits that use a common neutral.
the wobbly 240v is caused by out of sync sine wave. One is 60hz, the other is 59hz. Due to wave cancellation, the two legs will seem to wander from zero to 240v. With Some inverters you can sync them together using the master as the clock. The slave is programmed to be out of sync by 180 degrees of the master clock giving you true 240v from two 120v sources.
I think you're right about the frequency between the 2 power supplies. When I was in the service, sometimes we had to run 2 generators to handle a very large load. The generators had paralleling light that would flash when it was correct to add the second generator so the frequencies were the same.
Naomi must have attended the same school of Wifery that my wife attended. I learned that when I want to do something like that, to do it when they're shopping or visiting my inlaws.
I think you can overload your neutral this way if your power sources can supply enough current. The two legs are meant to always be out of phase with each other, with the neutral carrying the difference, not the sum.
I do this all the time. It is an option on military genset older 1s. You have to synchronize the gen. exciter circuit. Using a resistance and you need to set the rpms of both Gensets with a tachometer. I use a harbor freight model. There are even control boxes you can buy on Amazon that come with an idle solenoid and adjustable knob.
Benjamin I did the same thing in my house. I have an eco flow and a APC. I connected a transfer switch I split the two hots with to 20 amps plugs. I connected one to the Ecoflow and the other to the APC or 3500 ways generator, if I choose to. Haven’t lost power but am ready if it does. Eco flow is the only one that can turn my boilers pump for oil heat.
Yeah, other comments have already said this, but I'm throwing my own confirmation in, too. The two inverters have slightly different frequency and will drift between full amplification (240VAC) and cancellation (0VAC) and back. This is actually how big generators are put into sync to either increase available voltage or amperage. One generator is put to a slightly different frequency and the voltage is monitored until the desired voltage is reached, then they are synchronized.
No surprise if you get varying voltage. To obtain 240 V the two hots have to be 120 V in opposite phase. Unless your sources sync those phases and invert one with respect to the other, it's a no-go.
It'd be interesting to see whether using a generator to only charge the batteries would use less fuel overall compared to just running the generator to power the house for the same time period. The generator would have a higher power output over a shorter period of time if it's only used to charge the batteries which would burn more fuel per hour compared to a smaller load. If the generator was used to power the house full time, the assumption would be that it would output less power (compared to charging the batteries) and thus use less fuel per hour it ran. Begs the question, at what power output level is the generator most efficient? Does the loss of going in and out of a battery pack have any impact? I'd love to see a video testing some theories!
Part throttle power on a gas motor is very low efficientcy. Generally 70% throttle is optimum. So, in theory, better to power tge gen at 70% for a short period. But you must compare that efficiency gain vs the loss that the battery causes (charge vs discharge losses). Likely better with the batteries if they are large enough.
@@markhischier2750 Generators need to run at 3600rpm to get 60hz (not sure if this differs for inverter style) so the throttle level wouldn't differ, it would only be the load on the engine at that 3600rpm that would change.
Speaking of faulty 2-pole breakers, my friend thought he had turned off his stove breaker. Luckily he tested the legs and apparently only one side was actually off! Always test before touching.
You can get a generator plug cord that just goes to one 120V plug and ties the two hot legs together. This seems to be a safer solution. Unless you have a split phase inverter or linkable/syncing inverters you can't run both legs and get the 240V to work.
Although I have not read all comments, I do see some saying that both phases have to be in phase with each other. It’s actually that the two 120v phases are 180 degrees out of phase with each other. That is how you actually get 240v is because while “A” phase is going 1 positive the other is going negative do you actually have a total RMS voltage of 240v. I know for a lot of generators you can purchase a special sync setup that will ensure that when connected together they stay 180 degrees from each other therefore allowing you to use a limited number of your 240v circuits.
I bought a brand new Siemens 30 amp breaker from the store when I was installing my generator lockout / power inlet box on my house. (which was fully inspected by the city inspector) When I completed the install I started checking and verifying voltages with my digital multi meter and I found one side of my panel was dead while running on generator power. I narrowed it down to a bad breaker. Same deal you had here.... I had continuity through one pole on the breaker, but not the other. Brand new breaker, bad from the store. Weird.
I think everyone that commented are saying about the same thing. The two power generators are running independently of each other frequency wise and are not in sync with each other. If the two 120vac generators were able to be synced together they would have to be 180 deg out of phase so you would have steady 240 vac voltage. You would have to be careful not to pull any more load then what the generator with the lowest wattage rating is.
I have been thinking of using a dual 120 volt output generator with this type of cord. I need to make sure it has a common neutral and ground, I like the videos your making. I knew the cause of the voltage differences right away and feel that my generator wont cause that issue
Measuring voltage is measuring potential difference in phase rotations aka sine waves. Synchronous phases = 0v potential :-) That being said, I have many acquaintances that power their panel with a 120v generator, and do so by merging the phases in the cord itself and turning off the 240v loads. The whole panel is powered, just with 120v on both sides in phase :-)
What a fun and interesting test. Keep em coming! Funny call @6:28 Interesting 0 volts on 1 leg. Didnt expect that @9:45 Haha at the rewind flashback @10:26 Cool flashlight and dust blowing! @10:55 Cool tip to test breakers @12:10
The frequency of the two Battery backup/inverter systems is more than fine. The issue is that they are not synchronized together at 180 degrees. So what you are seeing is that as they slowly drift in and out of the relative phase with each other unit, the apparent voltage across them will constantly change/drift relative to the other.
I was hoping you had a way to actually power the 240v with two 120v generators. Most generators that can be connected with a parallel kit will synchronize frequency when connected. I was hoping you had discovered a way to actually get the two generators out of phase and actually get a consistent 240v. The voltage between the two hot legs varies from 0v to 240v in your case because the generators are not exactly 60 hz and are not synchronized together.
I have a generator that only has 2 120volt outlets. I have 2 male to male extension cords to power my house when RG&E goes down. I hook up one extension to the outlet in one bedroom and the other in another bedroom on the other side of the house. Of course, I turn off main power to the power company. everything works. I don't try to run 220-volt water pump or dryer. Gets me by during the outage. I wrote to you about this a long time ago. When I ran one extension cord in the garage it would not run my furnace or refrigerator. By doing the above all works great.
the light going bright to off then back off is showing the phase difference. you can use this method to sync 2 gensets (engine driven) into parallel mode.
Besides what everyone else posted about the two generators not being in phase, actually they need to be 180 degrees out of phase and exactly the same frequency. If you have any multiwire branch circuits, these are two circuit one on each leg that use a common neutral conductor. Normally since each leg is 180 out of phase with the other the neutral only carries the difference current. If the loads are exactly balance the neutral carries zero current. Worst case using two generators if they are both in phase the neutral now has to carry the combined current of both logs. Needless to that that is not a good thing.
I agree with the other commenters. The two inverters are out of sync and could be running at different frequencies, and not exactly 60 hz. It's possible one is 59 hz and the other is 61 hz, which would cause the voltage between the two hots to vary between 0-240 volts. The same applies to 2 gas powered generators that use an inverter. There are parallel kits to connect two identical generators for more current capacity but the output voltage is still 120 volts.
I was an electrician on locomotives. When working on cab signal you has to use analog meters because of induction. I may be wrong in this case. With enough induction going on you just get the probes close and you get what some people call ghost readings,🍄🤣
Actually, in the normal electrical power you get from the electric company, each of the two 120 Volt lines coming into the breaker box are exactly 60 Hz and exactly 180 degrees out of phase. This results in 240 VAC as measured line to line. Now, when you try to connect two stand alone AC sources; and measure line to line; since each independent source is generating power and not synchronized to the other, the phase of each relative to the other is random and therefore when you measure line to line across the two sources, you will always see random voltage values, which is exactly what he saw. 😊
Of course you can, as long as you don't have any 240v devices, some random phase between the two legs. If you can lock the phases " in phase " you will see 0V across the two legs. If you can lock the 2 phases " 180 degrees out of phase " you will see 240V
Unless you know as much or more about electricity and power distribution than Benjamin, your best bet to stay alive and not burn down your house is to have a professional electrician install a transfer switch that cannot have both utility and generator power applied at the same time.
I have 2 transfer switches mounted and trying to figure out how to run gas generator on 220 volt while simultaneously running a solar generator on 120 volt lighting on the same 200 amp panel.
I'm sure someone commented this already... your "generators" have a "forced" common neutral with the cord plugged in. So neutral to hot on either is 120V. But the phase is not in sync. Thus, reading hot to hot will give various volts from roughly +240 to -240 as the phases cycle "across" each other. Peak voltage depending on the initial phase offset of the legs. An oscilloscope at this point would show this clearly. It is possible the frequency is different, but that woukd give a slow drift of voltage not the rapid change you are seeing since your meter is taking the RMS (root mean square) average of the AC voltage seen by your probes.
I'm pretty certain that the sense monitor is actually a 120v device that only uses the 2nd hot to monitor the voltage on that leg. When I was playing with mine originally I didn't have a 240v breaker and accidentally powered it on a single leg while doing some troubleshooting.
How about powering both legs of a panel through a interlocked breaker with a 110 inverter generator? Probably could leave 220 breakers on since its the same voltage? Great video Ben! Nice to see a family man on you tube
Benjamin, I would recommend re-checking all of the 240V circuits/devices. Some things might not have been happy with the fluctuating voltages. (like motors, or any 240V appliance with electronic controls)
You could also plug both plugs into the same battery/inverter. Outback power used to make a device that would allow their inverters to stack and frequency match. The catch is that you have to have inverters that can stack.
Drilling out the rivets is a quick clean way to disassemble breakers. That's pretty funny that the breaker had actual bugs in it. Your panel is outside, so yes I guess that's a risk. I see plenty of spiders, wasps, etc in my outdoor panels, so it might be worth leaving some mothballs in them.
There’s an easier way to back feed your panel with 120 Volts. disconnect all your 240 Volt loads. Take a regular 120 V extension cord. Cut the end off and install an L 1430 plug and jumper the hots in the plug. when you backfeed your panel you will now have 120volts to both legs . Definitely need to keep the 240 loads off. Love your show……
If you have any multiwire branch circuits, which have shared neutrals, you could potentially overheat the neutral wire inside your wall. So, exercise caution if pulling much over 10 amps on both circuits sharing a neutral.
The generators performed exactly as I suspected they would. Unless they are and could remain perfectly synchronized an at the same frequency, the voltage will slowly move up and down between 220v and zero.
Yep for sure looks like everybody figured that one out your power banks are out of phase you get to 240v and then they drop down to zero FYI somebody I think it might be Honda has generators you can hook two 110 generators together with a cord and they will phase in sync then you can get to 240v.
@@ricklee4 Yes, now I remember, it can increase or double the wattage. 50 years ago, while I was doing HVAC commercially, we had a situation after a fire in a restaurant. We needed to keep the 110 refrigeration coolers in operation till more permanent repairs were made. We simply jumped one leg to the other in the main box and use the only 120v generator (a Coleman 1200 Watt) we had available at the time. The Service was disconnected at the pole. Till repairs were completed. Nowadays if you need 240 volts there's a lot of cheap small generators on the market (HFT). It's cheaper than using two small 120v generators Panel interlock is great idea, it saves you from lighting up your neighbors, or power company employees in an emergency power outage situation. Ben, you're doing a great job, keep up the good work. I'm retired now but love watching everybody else work. thanks.
I haven't watched the video but I'm going to make my prediction here and leave this comment unedited. Based on my understanding of phases, you cannot use two generators to power 240 volts because the phases are not synchronized (reversed). Not only that but the neutrals are not connected either.
@Robert Swaine it’s not because the frequencies are slightly off, it’s because they are not synchronized and each phase is at a random located based on time based on when the generators were turned on. I’m sure you can time them and come up with a sequence when to turned them on to get 240 AC but they will eventually drift off again because clocks drift. You would need some type of sense wire and logic between the two to dynamically adjust the clocks so they remain timed.
Robert Swaine is mostly correct. But, if you can get the two seperate generators synced up and on line, the load will keep them synced. The most straight forward way would be to have 2 oscilloscopes monitoring the phase of each generator. Throw generator 1 on line. Then, when the phase of both generators synce up with each other, that would be 180 degrees out of phase, throw generator 2 on line. Tip. (Generator phase does not run at a perfect 60cycles, they vary typically by as much as 3-5 cycles or hertzs.) So 2 seperate genefators can eventually synce up there phase.
Enjoyed the video I new you were going to get the 240 before it showed, 1st I was thinking it was like breaker for water heater but I was thinking phase slightly off between. 2 sources but it was slight frequency difference between the 2 inverters. They actually have those battery storage devices with inverters that can give you 240 volts! You called them generators as many do, but they are batteries with inverters/ solar panels and not generators. But it made for interesting video!
The power banks use PWM to produce a simulated ac wave each independent of the other. They are not syncronized so the variation of voltage between the two sources is due to their frequency being slightly different. BTW if you wanted to syncronize two IC powered generators you clould have a switch up stream of a common bus. If you could close the switch to parallel the alternators when their output frequencies match they would be magnetically locked in sync and should be ok as long as both generators run.
I recommend using something like "Voltage Converter Transformer 5000W Watt Heavy Duty Step Up/Down 110V to 220V Home Commercial Voltage" This transformer available on Amaz for US$ 120. Problem with phase and frequency SOLVED!
The phase difference between the two signals would only affect the magnitude of the resulting signal, but it will still give a uniform output (sine wave). Difference in frequency,however, would result in a sine wave with variable extremes (max and min), resulting in a variable rms. I believe this could be solved if you use exact inverters from the same manufacturer. Some do have a connection for the proper phase shift too.
I have a Honda 2200 i where I Use a 30 amp 120 volt wire to hook to a L14 240 volt plug . On the L14, I tie the Xand Y together with a jumper. That way I get both sides of the panel.. Turning off all of the 240 breakers and I have no Multi wired shared circuits. So far it works very well, and only use some lights and 2 fridge and box fan or heat. I use this instead of my larger generator for short outages... Also with my Duromax 5500 It seems to run my computer and Tv with no interference issues.
Even if the two frequencies are identical, they are not synchronized. Therefore, other than never being more than the combined value of two voltages, the voltage between the two hots cannot be determined / predicted. However, there's another issue. That has to do with the possibility of overloading one or more neutral conductors. Because your temporary power sources fall far short (less than half) of that which could be supplied from the grid, it's unlikely to be a problem on the feed neutral supplying power to your house. However, depending on what is allowed on residential systems in your district, you should also be aware that some 115 vac circuits could have been supplied with physically connected / joined, but separately switched, 230 vac breakers.. For example, duplex receptacles in some kitchens in NA have been supplied with 230 vac with the hot side bonding bar removed so as to deliver 115 vac of opposite polarities to each individual outlet on the receptacle. The fact that the two outlets are fed off opposite legs, allows for the sharing of one neutral. Feeding that type of combined 115 vac circuitry, with two unsynchronized sources can easily over load the neutral as only the hot side wiring is protected with circuit breakers. Thank you for the video. I appreciate what you're trying to do, but, if I were you, I would seriously consider taking the video down. There are too many opportunities in it for folks to screw up and have the end result of you having to defend yourself in a very expensive court system.. even if you prevail in your defense. Best of luck, Dennis
Ben, question, a standard house main panel has two separate legs of 120 to which are separate Phases of electrical voltage supply. IE: left vs right legs on the panel How do you verify or test for this 120 volt phase output difference. That’s question one Question two is would it not better or safer to have the same power supply for each leg to insure the same consistency of voltage output
I was prepared to yell at you but then you turned off the 240 volt suff. Then again your smarter than that. In the event of a power outage, would a generator or power bank get damaged when the power came back on? I understand not back feeding the utility to protect people working on the power lines. Beautiful family by the way.
You should use same clock (oscillator), one inverted, or just phase and neutral inverted, for both inventors. Grid has its own solutions, there are electromechanical generators running. Inverters can not be coupled, i belive, but with single clock. Check me twice for safety.
I just tested attaching a generator to our house yesterday - bad weather in the forecast, and I wanted to check for unexpected surprises. The local codes now require GFI breakers in the panel in the garage, so just about every breaker is GFI, including the 50A dual breaker I used to feed the generator to the house. After a little thought, I decided to disconnect neutral and ground at the generator, since the return current would split between neutral wire and the ground wire in the generator connection cable, which would certainly cause enough imbalance to trip the GFI breaker. But when I closed the 50A breaker with the generator running, it made a buzzing noise for a second or two, then emitted a brief pop and some sparks from inside the breaker itself, and it tripped off. I gingerly reclosed the 50A GFI breaker, and this time it held with no buzzing sound. I then pressed the GFI test button on the breaker and . . . nothing. I apparently blew the snot out of the GFI circuit inside the breaker, and I have no clue as to why this happened. The rest of my testing was uneventful. (None of the other GFI breakers in the panel tripped; I was a little worried about this, because I have heard that GFI circuits are particularly sensitive to higher frequency harmonics, and I don't know how 'clean' my generator's output waveform is.) Afterwards, I decided to replace the blown 50A GFI breaker with a non-GFI breaker, since I wasn't 100% sure it was still safe to use. Just like the breaker you smashed in the video, my dead breaker was held together with five long aluminum rivets going through the width of the breaker. I tried to drill out the rivets, which worked on one, but the others just spun in place. Then I grabbed a nail punch and a hammer, and the other rivets popped right out, quick and easy. Using this method of opening the breaker, I was able to examine the innards in their unmolested state. There was a little circuit board with the Permalloy core with the L1/L2/N wires running through the core. I expected to see one or more of the components on the circuit board visibly fried, but everything looked clean. Anyway, it's still a mystery to me why the GFI breaker fried. I realize that they are designed for power flow in the other direction, but I don't understand how the circuit would 'know' which direction power is flowing.
Update: Going back over the process of replacing the fried GFI breaker with the standard breaker, I realize now that the GFI breaker was wired incorrectly; the neutral wire from the 50A outlet was connected to the neutral bar in the breaker panel, but it should have been connected directly to the GFI breaker, along with the two hot wires. The neutral pigtail wire from the GFI breaker was wired to the neutral bar, so at least they got that part correct. So, the electrician miswired the breaker, and the inspector missed it. Apparently the 50A outlet had never been used before, or was used with a pure 240V load with no neutral connection. With the missing neutral, I subjected a sensitive circuit designed to trip on 5mA of current to maybe 1000x that much current, so it doesn't surprise me that it failed.
I wanted to know whether or not I'm going to get 240V out of my 120V generator. I would connect the Y-cable that you have to the two sockets of the generator. It's clear that - if they were connected to poles, they would be perfectly in sync and thus I would get 240V. If they're connected to the same pole I should get perfectly 0 volts. But how are 2000W generators wired?
Interesting experiment. I would have never thought to hook up a generator to each leg. I would have thought there possibly could have been a problem with the polarity flow & that it may have tripped breakers (is this why u shut off all 2 pole breakers?) . I would have been worried that the power banks didn't send current in the same direction as the utilities. I would have had too much apprehension to try this experiment at my home. I would have been worried that I would cause damage to my appliances or power banks. Thanks for showing everyone this experiment.
test with two similar/same battery generators to see if the inverters don’t drift. Can you confirm if the inverter in the gen set is a pure SINE WAVE…. ? I like the idea as I have a rural property where power outages are frequent but no protracted. It would be goo to have a way to see when the CO-OP is back even when on the batt/gen for power… a sensor? I also like your idea of the gas gen set to recharge the batt gen set to extend the back up power. Kudos
power from generators at power plants are 3 phases each cycling up and down as generator turns each rotation. you only get one phase run to each local transformer the thin wire on top it has to be in perfect sync and phase because the transformer just splits it into two 120-volt legs from 11,000 volts coming in so you get 240 volts across both because it is rising and falling at same time, so it doubles voltage if they were out of sync they can't add up this why ac electric motors run at same speed either 1750 or 3500 rpm depending on how many coils and magnets they have to match 60 cycles per second
It's not weird you're not synced in phase... Or out of phase you have two separate 120 volt sources that are random. This is also alternating current you know that current travels on your neutral right? And the voltage reverses 60 times a second right? In other words the two sources are not independent when you combine the neutrals.
Would that not be the same as connecting to dual pole breaker like the one for your water heater which gives you 240 volts? I think So, but actually depending on your power sorces it will be like 2 single poles each giving you 120 = 240 volts
The reason you are seeing the voltage changing between the to hot legs is the two inverters are not running at EXACTLY 60 hz....so their phase is not synchronized. What is happening is as the inverters come into phase with each other you will see 0 volts. And the voltage will rise as they go out of phase until they reach 180 degrees our of phase, showing you a peak voltage, approx 240v.
You can tell exactly how many cycles apart they are by timing the how long it takes from peak to peak.
This is how power generation plants sync with the grid before closing their interconnect with the grid. They monitor the voltage between the interconnect and their generator. They adjust the RPM so the cycles are VERY close. Then they wait for the zero crossings match and close the circuit. You can do the same thing with multiple generators connected to your home at the same time.
Exactly. That tool is called a Synchroscope by the way.
Yes...the very reason some gennys have a sync option.
I learned about generator synchronization in a video game: Infra
@@Icehso140 Do you know which brands do this? When I was looking for two 3k inverters to do that, all I could find were parallel kits that sync'd to be in phase, providing more amps but at 120 volts. I could not find any that would sync 180 out of phase to produced 240v.
100% correct and well explained. An interesting case is that once the generator is synched and connected to the grid, it is very difficult to get it out of sync or out of phase because the grid will resist those changes.
The drifting phases assumptions are correct. Some inverters are equipped to automatically synchronize as a cooperating pair, providing center-tap style 120v/240v. I have a pair of Xantrex 2 kw inverters, new in 2007, that are configured so. They work flawlessly, including auto cut-over, auto phase synchronization, with an absolutely perfect waveform. The inverter pair easily power the 120v and 240 loads including the range-top, oven, HVAC (A/C, furnace blower, etc.), at 4 kw continuous, 6 kw peak/surge. Each inverter is also a 100 amp, fully computerized battery charger keeping my bank of golf-cart batteries in tip-top condition. The cascading power sources are mains, solar, and finally propane fueled generator. When the mains fail, the generator, solar panels, or batteries power the inverters which are always carrying the load.
I think the two separate battery banks are drifting in and out of phase with each other since their inverters are not electronically synced to each other in any way.
Precisely.
@@BenjaminSahlstrom And now you know how balanced the load is on both legs. And you found the bug in the system. You debugged it!
@@BenjaminSahlstrom I think ecoflow sells a device that lets you use 2 of their "generators" to get 240 by handling the phase issue.
Quite literally! Ha!
Really? That would be interesting to take a look at.
Edited with more info: There are two reasons for the 240 volt problem. Number one as you mentioned the frequencies are probably not exactly the same. However, the second problem is that they are also not going to be in phase with each other.
Even if they were both electronically synced to be exactly the same frequency, it's unlikely they would be in phase with each other. If they WERE synced to be the exact same frequency but NOT synced to be in phase, you would see some STEADY voltage between 0 and 240 depending on the phase difference.
In any case, if you were to look at a graph of the two 120V sine waves above each other WITH ONE INVERTED, the voltage at any moment in time would be the sum of the 2 voltages at that point in time. (Or on the graph, if the sine wave displays are touching each other, it would be the voltage equivalent to the distance between the two points at that moment.)
Another way to think of it is that the voltage on the 240 connection is the sum of the instantaneous voltage of the two sources at any point in time. Please keep in mind that the instantaneous voltage can be positive or negative at any moment in time. (I don't want to complicate things but for those that might try to point this out, yes the meter probably measures RMS, and the graphs would show peak which can go much higher than 240, but the basic principle is there.)
I apologize if anyone else said the same thing but I haven't read all comments. An interesting experiment. I enjoy your channel.
on the bright side, it was much better that you discovered that the breaker was faulty outside a real power outage or an emergency, which is why we must periodically test all power systems, especially those that are infrequently used. Cheers from Brazil.
You nailed it… the frequency between the two separate power sources are not synchronized. One is probably running at something like 58hz. 😂and the other at 63hz. So there sine waves were sometimes in opposition and other times they were in parallel thus cancellation.
Theyre bothnrunning at 60 but they are not starting at the same time.
Exactly. They're probably both at 60 hertz but not exactly and the phase shift allows them to be in sync and then out of sync causing the voltage differences over time.
You have frequency and shift between the two frequencies based on time. The 240 voltage is based on the shift in the frequencies not the frequency itself.
I find the thinking process to be real cool. With all the new tech coming out this puts some new ideas in the air. thanks for demonstrating this to all of us.
What it impresses me is his wife. She looks so confident about her husband messing with the power while preparing dinner.
Lucky him. Lol
The varying LED is an example of what in physics is called 'beats". You can hear the same thing happen when you have two different tones play that are slightly different frequencies.
With the beat frequency you can measure the difference in frequency between the two sources So if one is 59hz and the other is 60hz, you'd hear a beat frequency of 1hz.
Yours looked like a frequency of about 8-10 seconds, so you'd expect a difference between the two of something like .1hz. For example, one might be 59.8hz and the other is 59.9 hz.
I showed part of this to my wife and her comment 'yup, the husband is always the biggest kid'. Cool video and test.
You should also turn off any multiwire branch circuits, since these circuits share a neutral. (Which of course should have a shared breaker). I'm not really sure what would happen with these circuits since they share a neutral, but at the very least you'd be out of code since they no longer will balance any load between the two phases, since as you observed they aren't.
The US National Electric Code (NEC) 2020 edition requires that all Multi Wire Branch circuits (MWBC)s have one of two arrangements of the circuit breaker/s supplying them. Either handle ties or a double pole breaker. If it's a 2 pole breaker that would take care of the neutral overloading issue of MWBCs when you threw all of the double pole breakers to off with the caveat that the requirement for special control of MWBCs is relatively recent and it is unlikely that any but rather recent panels have been upgraded to comply with this new requirement. If handle ties are used then you would have to treat all of the handle tied breakers the same as double pole breakers and turn those off as well.
Tom Horne
Similar to a 120v generator feeding both panel legs with 240v breakers off. Best to use single breakers protecting eack leg separately. If one leg goes over current, only one leg will drop out.
Great video proof it can be done safely.
Speaking as an IT professional I would say the problem with your second leg is that you have a bug in the system!
It depends. If you develop software, it’s a hardware problem. If you maintain hardware, it’s a software problem. If these two fail then it’s a network problem.
Network guys: we didn’t make any changes. (Oh, wow, how many times have heard that.)
Lol
That weird voltage you are seeing across the 240V is the 2 power sources are out of phase with each outher .If you you have a dual trace scope you can see the two wave forms and you can see they both do not line up. On the larger power banks there is a sync cable to go between them and that will fix that 240V problem. Also some generators have a sync cable as well . like the larger Honda inverter generator . also can put 2 120V loads together for more amps. I made a cord like you use in video but used 10/3 wire for the 2 legs and 20A 120V plug. I have gen set that output 20 amps 120V + . also both 120V plugs can be put into same source .being 180deg out of phase there will be 0 volts between the 2 hot legs. is ok to do this ,same again 240V loads turn off. I have been a electrician in Boston NY over 30 years now and had my share of bugs getting inside panel box and breakers. I keep bee and bug spray on hand. Them little things can find a way in. nice video. 😀
Southwest Missouri here, it was an interesting experiment. Really liked it. As others have mentioned using actual generators would be another interesting scenario thanks for the video
Awesome video. I have been thinking along these lines as well. I have 24 250W solar panels. 12 go to one solar charge controller/inverter and 12 go to another. Each of these have their own 10KW battery bank. They each put out 120v. If I connected them together and connected a data cable between them I could configure the inverters to output 240V but the 2 units have to be on a shared battery bank. And my lithium battery banks are identical in configuration (4 12V 200AH) but each bank of 4 batteries are of a different manufacturer. Also I had read a data sheet from one of the manufacturers to not exceed 4 batteries in one bank. So, I have been hesitant to run my two inverters in sync with each other to get the 240v and sidelining a perfectly good bank of 10KW. So this has been on my mind a lot lately. Thanks for the additional thought material!
Need to have two of the same brand/size generators and have a sync option otherwise they will be out of phase. I think there might be a problem with 2 120 volt circuits that use a common neutral.
the wobbly 240v is caused by out of sync sine wave. One is 60hz, the other is 59hz. Due to wave cancellation, the two legs will seem to wander from zero to 240v. With Some inverters you can sync them together using the master as the clock. The slave is programmed to be out of sync by 180 degrees of the master clock giving you true 240v from two 120v sources.
They have different sine waves and they are not syncing together like a normal 240 generator
I think you're right about the frequency between the 2 power supplies. When I was in the service, sometimes we had to run 2 generators to handle a very large load. The generators had paralleling light that would flash when it was correct to add the second generator so the frequencies were the same.
Naomi must have attended the same school of Wifery that my wife attended.
I learned that when I want to do something like that, to do it when they're shopping or visiting my inlaws.
In a split phase system the 120 legs need to be 180 degrees out of phase from each other to get a full 240 voltage between them.
I think you can overload your neutral this way if your power sources can supply enough current. The two legs are meant to always be out of phase with each other, with the neutral carrying the difference, not the sum.
I do this all the time. It is an option on military genset older 1s. You have to synchronize the gen. exciter circuit. Using a resistance and you need to set the rpms of both Gensets with a tachometer. I use a harbor freight model. There are even control boxes you can buy on Amazon that come with an idle solenoid and adjustable knob.
Benjamin I did the same thing in my house. I have an eco flow and a APC. I connected a transfer switch I split the two hots with to 20 amps plugs. I connected one to the Ecoflow and the other to the APC or 3500 ways generator, if I choose to. Haven’t lost power but am ready if it does. Eco flow is the only one that can turn my boilers pump for oil heat.
Great family Ben and Naomi. Need more of this in America. God bless
Yeah, other comments have already said this, but I'm throwing my own confirmation in, too. The two inverters have slightly different frequency and will drift between full amplification (240VAC) and cancellation (0VAC) and back.
This is actually how big generators are put into sync to either increase available voltage or amperage. One generator is put to a slightly different frequency and the voltage is monitored until the desired voltage is reached, then they are synchronized.
Basic rule #1: Never begin with electrical works when night is falling down... 👀
No surprise if you get varying voltage. To obtain 240 V the two hots have to be 120 V in opposite phase. Unless your sources sync those phases and invert one with respect to the other, it's a no-go.
It'd be interesting to see whether using a generator to only charge the batteries would use less fuel overall compared to just running the generator to power the house for the same time period. The generator would have a higher power output over a shorter period of time if it's only used to charge the batteries which would burn more fuel per hour compared to a smaller load. If the generator was used to power the house full time, the assumption would be that it would output less power (compared to charging the batteries) and thus use less fuel per hour it ran. Begs the question, at what power output level is the generator most efficient? Does the loss of going in and out of a battery pack have any impact? I'd love to see a video testing some theories!
Check out Edison motors, he’s doing this exact thing on his diesel electric semi-truck
Part throttle power on a gas motor is very low efficientcy. Generally 70% throttle is optimum. So, in theory, better to power tge gen at 70% for a short period. But you must compare that efficiency gain vs the loss that the battery causes (charge vs discharge losses). Likely better with the batteries if they are large enough.
@@markhischier2750 Generators need to run at 3600rpm to get 60hz (not sure if this differs for inverter style) so the throttle level wouldn't differ, it would only be the load on the engine at that 3600rpm that would change.
Speaking of faulty 2-pole breakers, my friend thought he had turned off his stove breaker. Luckily he tested the legs and apparently only one side was actually off! Always test before touching.
You can get a generator plug cord that just goes to one 120V plug and ties the two hot legs together. This seems to be a safer solution. Unless you have a split phase inverter or linkable/syncing inverters you can't run both legs and get the 240V to work.
Although I have not read all comments, I do see some saying that both phases have to be in phase with each other. It’s actually that the two 120v phases are 180 degrees out of phase with each other. That is how you actually get 240v is because while “A” phase is going 1 positive the other is going negative do you actually have a total RMS voltage of 240v. I know for a lot of generators you can purchase a special sync setup that will ensure that when connected together they stay 180 degrees from each other therefore allowing you to use a limited number of your 240v circuits.
I bought a brand new Siemens 30 amp breaker from the store when I was installing my generator lockout / power inlet box on my house. (which was fully inspected by the city inspector) When I completed the install I started checking and verifying voltages with my digital multi meter and I found one side of my panel was dead while running on generator power. I narrowed it down to a bad breaker. Same deal you had here.... I had continuity through one pole on the breaker, but not the other. Brand new breaker, bad from the store. Weird.
I think everyone that commented are saying about the same thing. The two power generators are running independently of each other frequency wise and are not in sync with each other. If the two 120vac generators were able to be synced together they would have to be 180 deg out of phase so you would have steady 240 vac voltage. You would have to be careful not to pull any more load then what the generator with the lowest wattage rating is.
I have been thinking of using a dual 120 volt output generator with this type of cord. I need to make sure it has a common neutral and ground, I like the videos your making. I knew the cause of the voltage differences right away and feel that my generator wont cause that issue
Measuring voltage is measuring potential difference in phase rotations aka sine waves. Synchronous phases = 0v potential :-)
That being said, I have many acquaintances that power their panel with a 120v generator, and do so by merging the phases in the cord itself and turning off the 240v loads. The whole panel is powered, just with 120v on both sides in phase :-)
What a fun and interesting test. Keep em coming!
Funny call @6:28
Interesting 0 volts on 1 leg. Didnt expect that @9:45
Haha at the rewind flashback @10:26
Cool flashlight and dust blowing! @10:55
Cool tip to test breakers @12:10
The frequency of the two Battery backup/inverter systems is more than fine. The issue is that they are not synchronized together at 180 degrees.
So what you are seeing is that as they slowly drift in and out of the relative phase with each other unit, the apparent voltage across them will constantly change/drift relative to the other.
I was hoping you had a way to actually power the 240v with two 120v generators. Most generators that can be connected with a parallel kit will synchronize frequency when connected. I was hoping you had discovered a way to actually get the two generators out of phase and actually get a consistent 240v.
The voltage between the two hot legs varies from 0v to 240v in your case because the generators are not exactly 60 hz and are not synchronized together.
I have a generator that only has 2 120volt outlets. I have 2 male to male extension cords to power my house when RG&E goes down. I hook up one extension to the outlet in one bedroom and the other in another bedroom on the other side of the house. Of course, I turn off main power to the power company. everything works. I don't try to run 220-volt water pump or dryer. Gets me by during the outage. I wrote to you about this a long time ago. When I ran one extension cord in the garage it would not run my furnace or refrigerator. By doing the above all works great.
the light going bright to off then back off is showing the phase difference. you can use this method to sync 2 gensets (engine driven) into parallel mode.
240 amplitudewill exhibit the beat frequency that will be the difference of the two frequencies. Now back to the vid....
Besides what everyone else posted about the two generators not being in phase, actually they need to be 180 degrees out of phase and exactly the same frequency. If you have any multiwire branch circuits, these are two circuit one on each leg that use a common neutral conductor. Normally since each leg is 180 out of phase with the other the neutral only carries the difference current. If the loads are exactly balance the neutral carries zero current. Worst case using two generators if they are both in phase the neutral now has to carry the combined current of both logs. Needless to that that is not a good thing.
Great point. I hadn't thought of that.
But once this is all hooked up, can you use a 240V appliance?
I agree with the other commenters. The two inverters are out of sync and could be running at different frequencies, and not exactly 60 hz. It's possible one is 59 hz and the other is 61 hz, which would cause the voltage between the two hots to vary between 0-240 volts. The same applies to 2 gas powered generators that use an inverter. There are parallel kits to connect two identical generators for more current capacity but the output voltage is still 120 volts.
Dude!! You got 5 kids!!! You got watch tv more.😂😂
He’s making the TV (UA-cam vids) you’re watching! 😂
I was an electrician on locomotives. When working on cab signal you has to use analog meters because of induction.
I may be wrong in this case.
With enough induction going on you just get the probes close and you get what some people call ghost readings,🍄🤣
Actually, in the normal electrical power you get from the electric company, each of the two 120 Volt lines coming into the breaker box are exactly 60 Hz and exactly 180 degrees out of phase. This results in 240 VAC as measured line to line.
Now, when you try to connect two stand alone AC sources; and measure line to line; since each independent source is generating power and not synchronized to the other, the phase of each relative to the other is random and therefore when you measure line to line across the two sources, you will always see random voltage values, which is exactly what he saw. 😊
Of course you can, as long as you don't have any 240v devices, some random phase between the two legs.
If you can lock the phases " in phase " you will see 0V across the two legs. If you can lock the 2 phases " 180 degrees out of phase " you will see 240V
Unless you know as much or more about electricity and power distribution than Benjamin, your best bet to stay alive and not burn down your house is to have a professional electrician install a transfer switch that cannot have both utility and generator power applied at the same time.
I have 2 transfer switches mounted and trying to figure out how to run gas generator on 220 volt while simultaneously running a solar generator on 120 volt lighting on the same 200 amp panel.
I'm sure someone commented this already... your "generators" have a "forced" common neutral with the cord plugged in. So neutral to hot on either is 120V. But the phase is not in sync. Thus, reading hot to hot will give various volts from roughly +240 to -240 as the phases cycle "across" each other. Peak voltage depending on the initial phase offset of the legs. An oscilloscope at this point would show this clearly.
It is possible the frequency is different, but that woukd give a slow drift of voltage not the rapid change you are seeing since your meter is taking the RMS (root mean square) average of the AC voltage seen by your probes.
I'm pretty certain that the sense monitor is actually a 120v device that only uses the 2nd hot to monitor the voltage on that leg. When I was playing with mine originally I didn't have a 240v breaker and accidentally powered it on a single leg while doing some troubleshooting.
How about powering both legs of a panel through a interlocked breaker with a 110 inverter generator? Probably could leave 220 breakers on since its the same voltage?
Great video Ben! Nice to see a family man on you tube
That was a lot of fun to watch! Thanks.
The only issue I can think is that the 2 120v legs could be out of phase.
Benjamin, I would recommend re-checking all of the 240V circuits/devices. Some things might not have been happy with the fluctuating voltages. (like motors, or any 240V appliance with electronic controls)
I to would like to see the video completed with 240 volt appliance's running
What about grid on one side and solar generator or gas generator on the other?
You could also plug both plugs into the same battery/inverter. Outback power used to make a device that would allow their inverters to stack and frequency match. The catch is that you have to have inverters that can stack.
Drilling out the rivets is a quick clean way to disassemble breakers. That's pretty funny that the breaker had actual bugs in it. Your panel is outside, so yes I guess that's a risk. I see plenty of spiders, wasps, etc in my outdoor panels, so it might be worth leaving some mothballs in them.
The 2 different power supplies are not synced.
There’s an easier way to back feed your panel with 120 Volts. disconnect all your 240 Volt loads. Take a regular 120 V extension cord. Cut the end off and install an L 1430 plug and jumper the hots in the plug. when you backfeed your panel you will now have 120volts to both legs . Definitely need to keep the 240 loads off. Love your show……
If you have any multiwire branch circuits, which have shared neutrals, you could potentially overheat the neutral wire inside your wall. So, exercise caution if pulling much over 10 amps on both circuits sharing a neutral.
The generators performed exactly as I suspected they would. Unless they are and could remain perfectly synchronized an at the same frequency, the voltage will slowly move up and down between 220v and zero.
Yep for sure looks like everybody figured that one out your power banks are out of phase you get to 240v and then they drop down to zero
FYI somebody I think it might be Honda has generators you can hook two 110 generators together with a cord and they will phase in sync then you can get to 240v.
@@ricklee4 Yes, now I remember, it can increase or double the wattage.
50 years ago, while I was doing HVAC commercially, we had a situation after a fire in a restaurant.
We needed to keep the 110 refrigeration coolers in operation till more permanent repairs were made.
We simply jumped one leg to the other in the main box and use the only 120v generator (a Coleman 1200 Watt) we had available at the time.
The Service was disconnected at the pole. Till repairs were completed.
Nowadays if you need 240 volts there's a lot of cheap small generators on the market (HFT).
It's cheaper than using two small 120v generators
Panel interlock is great idea, it saves you from lighting up your neighbors, or power company employees in an emergency power outage situation.
Ben, you're doing a great job, keep up the good work.
I'm retired now but love watching everybody else work.
thanks.
I haven't watched the video but I'm going to make my prediction here and leave this comment unedited. Based on my understanding of phases, you cannot use two generators to power 240 volts because the phases are not synchronized (reversed). Not only that but the neutrals are not connected either.
That's exactly what I thought and as you'll see that synchronization issue is observed shortly.
The neutrals are connected connected in the first breaker panel because they are both bonded to the ground.
@@jackpatteeuw9244 yes that’s correct. I was wrong about that
@Robert Swaine it’s not because the frequencies are slightly off, it’s because they are not synchronized and each phase is at a random located based on time based on when the generators were turned on. I’m sure you can time them and come up with a sequence when to turned them on to get 240 AC but they will eventually drift off again because clocks drift. You would need some type of sense wire and logic between the two to dynamically adjust the clocks so they remain timed.
Robert Swaine is mostly correct. But, if you can get the two seperate generators synced up and on line, the load will keep them synced. The most straight forward way would be to have 2 oscilloscopes monitoring the phase of each generator. Throw generator 1 on line. Then, when the phase of both generators synce up with each other, that would be 180 degrees out of phase, throw generator 2 on line. Tip. (Generator phase does not run at a perfect 60cycles, they vary typically by as much as 3-5 cycles or hertzs.) So 2 seperate genefators can eventually synce up there phase.
Enjoyed the video I new you were going to get the 240 before it showed, 1st I was thinking it was like breaker for water heater but I was thinking phase slightly off between. 2 sources but it was slight frequency difference between the 2 inverters. They actually have those battery storage devices with inverters that can give you 240 volts! You called them generators as many do, but they are batteries with inverters/ solar panels and not generators. But it made for interesting video!
The power banks use PWM to produce a simulated ac wave each independent of the other. They are not syncronized so the variation of voltage between the two sources is due to their frequency being slightly different. BTW if you wanted to syncronize two IC powered generators you clould have a switch up stream of a common bus. If you could close the switch to parallel the alternators when their output frequencies match they would be magnetically locked in sync and should be ok as long as both generators run.
the different legs are not out of phase by 180 degrees. Also, should be slowly raising and lowering as hertz are not identical. (rolling voltages)
I recommend using something like "Voltage Converter Transformer 5000W Watt Heavy Duty Step Up/Down 110V to 220V Home Commercial Voltage" This transformer available on Amaz for US$ 120. Problem with phase and frequency SOLVED!
Cool test ... I would never have tried it on my house unless it was an emergency, but the fire pump houses at work ... sure 😄👌.
The phase difference between the two signals would only affect the magnitude of the resulting signal, but it will still give a uniform output (sine wave). Difference in frequency,however, would result in a sine wave with variable extremes (max and min), resulting in a variable rms.
I believe this could be solved if you use exact inverters from the same manufacturer. Some do have a connection for the proper phase shift too.
I have a Honda 2200 i where I Use a 30 amp 120 volt wire to hook to a L14 240 volt plug . On the L14, I tie the Xand Y together with a jumper. That way I get both sides of the panel.. Turning off all of the 240 breakers and I have no Multi wired shared circuits. So far it works very well, and only use some lights and 2 fridge and box fan or heat. I use this instead of my larger generator for short outages... Also with my Duromax 5500 It seems to run my computer and Tv with no interference issues.
What if I had the adaptor he is using here and plugged both of them into the Honda 2200 would that be safe if I had some MWBC's?
Nice video. I have seen bugs, spiders, etc. get into breakers and contactors on AC systems. Glad you found yours. Thanks
Be interesting to see an O scope across the two.
Even if the two frequencies are identical, they are not synchronized. Therefore, other than never being more than the combined value of two voltages, the voltage between the two hots cannot be determined / predicted.
However, there's another issue. That has to do with the possibility of overloading one or more neutral conductors.
Because your temporary power sources fall far short (less than half) of that which could be supplied from the grid, it's unlikely to be a problem on the feed neutral supplying power to your house.
However, depending on what is allowed on residential systems in your district, you should also be aware that some 115 vac circuits could have been supplied with physically connected / joined, but separately switched, 230 vac breakers.. For example, duplex receptacles in some kitchens in NA have been supplied with 230 vac with the hot side bonding bar removed so as to deliver 115 vac of opposite polarities to each individual outlet on the receptacle. The fact that the two outlets are fed off opposite legs, allows for the sharing of one neutral. Feeding that type of combined 115 vac circuitry, with two unsynchronized sources can easily over load the neutral as only the hot side wiring is protected with circuit breakers.
Thank you for the video. I appreciate what you're trying to do, but, if I were you, I would seriously consider taking the video down. There are too many opportunities in it for folks to screw up and have the end result of you having to defend yourself in a very expensive court system.. even if you prevail in your defense.
Best of luck, Dennis
Hot to hot legs depends on phase. So your meter is confused. As they aren’t in sync at 240 or cancelling each other out.
Yes seeing the other comments they could be not quite in phase because they both are not going through same inverter
Thanks!
Your wife was about as interested as mine would be when you said it would be really cool. I get that look a lot. 😂
Ben, question, a standard house main panel has two separate legs of 120 to which are separate Phases of electrical voltage supply.
IE: left vs right legs on the panel
How do you verify or test for this 120 volt phase output difference. That’s question one
Question two is would it not better or safer to have the same power supply for each leg to insure the same consistency of voltage output
Lightning can damage breakers. Bugs in the breaker. The damage to your breaker was probably caused by lightning bugs.
😆
"... while Dad fixes the issue..." You meant "While Dad is causing the issue!"
the phase is not 180-360 degree, so the combine voltage changes continously
I was prepared to yell at you but then you turned off the 240 volt suff.
Then again your smarter than that.
In the event of a power outage, would a generator or power bank get damaged when the power came back on?
I understand not back feeding the utility to protect people working on the power lines.
Beautiful family by the way.
You should use same clock (oscillator), one inverted, or just phase and neutral inverted, for both inventors. Grid has its own solutions, there are electromechanical generators running. Inverters can not be coupled, i belive, but with single clock. Check me twice for safety.
I just tested attaching a generator to our house yesterday - bad weather in the forecast, and I wanted to check for unexpected surprises. The local codes now require GFI breakers in the panel in the garage, so just about every breaker is GFI, including the 50A dual breaker I used to feed the generator to the house. After a little thought, I decided to disconnect neutral and ground at the generator, since the return current would split between neutral wire and the ground wire in the generator connection cable, which would certainly cause enough imbalance to trip the GFI breaker. But when I closed the 50A breaker with the generator running, it made a buzzing noise for a second or two, then emitted a brief pop and some sparks from inside the breaker itself, and it tripped off. I gingerly reclosed the 50A GFI breaker, and this time it held with no buzzing sound. I then pressed the GFI test button on the breaker and . . . nothing. I apparently blew the snot out of the GFI circuit inside the breaker, and I have no clue as to why this happened. The rest of my testing was uneventful. (None of the other GFI breakers in the panel tripped; I was a little worried about this, because I have heard that GFI circuits are particularly sensitive to higher frequency harmonics, and I don't know how 'clean' my generator's output waveform is.)
Afterwards, I decided to replace the blown 50A GFI breaker with a non-GFI breaker, since I wasn't 100% sure it was still safe to use.
Just like the breaker you smashed in the video, my dead breaker was held together with five long aluminum rivets going through the width of the breaker. I tried to drill out the rivets, which worked on one, but the others just spun in place. Then I grabbed a nail punch and a hammer, and the other rivets popped right out, quick and easy. Using this method of opening the breaker, I was able to examine the innards in their unmolested state. There was a little circuit board with the Permalloy core with the L1/L2/N wires running through the core. I expected to see one or more of the components on the circuit board visibly fried, but everything looked clean.
Anyway, it's still a mystery to me why the GFI breaker fried. I realize that they are designed for power flow in the other direction, but I don't understand how the circuit would 'know' which direction power is flowing.
Update: Going back over the process of replacing the fried GFI breaker with the standard breaker, I realize now that the GFI breaker was wired incorrectly; the neutral wire from the 50A outlet was connected to the neutral bar in the breaker panel, but it should have been connected directly to the GFI breaker, along with the two hot wires. The neutral pigtail wire from the GFI breaker was wired to the neutral bar, so at least they got that part correct. So, the electrician miswired the breaker, and the inspector missed it. Apparently the 50A outlet had never been used before, or was used with a pure 240V load with no neutral connection. With the missing neutral, I subjected a sensitive circuit designed to trip on 5mA of current to maybe 1000x that much current, so it doesn't surprise me that it failed.
Holy Moly, Benjamin! Are those all your kids? That's quite the tribe. lol
Always great videos. Amazing your knowledge at your age. Thanks old retired carpenter superintendent
I wanted to know whether or not I'm going to get 240V out of my 120V generator. I would connect the Y-cable that you have to the two sockets of the generator. It's clear that - if they were connected to poles, they would be perfectly in sync and thus I would get 240V. If they're connected to the same pole I should get perfectly 0 volts. But how are 2000W generators wired?
So are you able to get 240v, on a double pole breaker. If you have one inverter hot, on one leg. And one inverter hot on the other?
Interesting experiment. I would have never thought to hook up a generator to each leg. I would have thought there possibly could have been a problem with the polarity flow & that it may have tripped breakers (is this why u shut off all 2 pole breakers?) . I would have been worried that the power banks didn't send current in the same direction as the utilities. I would have had too much apprehension to try this experiment at my home. I would have been worried that I would cause damage to my appliances or power banks. Thanks for showing everyone this experiment.
Super interesting, I love your electrical experiments!
test with two similar/same battery generators to see if the inverters don’t drift. Can you confirm if the inverter in the gen set is a pure SINE WAVE…. ? I like the idea as I have a rural property where power outages are frequent but no protracted. It would be goo to have a way to see when the CO-OP is back even when on the batt/gen for power… a sensor? I also like your idea of the gas gen set to recharge the batt gen set to extend the back up power. Kudos
power from generators at power plants are 3 phases each cycling up and down as generator turns each rotation. you only get one phase run to each local transformer the thin wire on top it has to be in perfect sync and phase because the transformer just splits it into two 120-volt legs from 11,000 volts coming in so you get 240 volts across both because it is rising and falling at same time, so it doubles voltage if they were out of sync they can't add up
this why ac electric motors run at same speed either 1750 or 3500 rpm depending on how many coils and magnets they have to match 60 cycles per second
Ben have you tested for journeyman's license yet. If not you really should very sharp dude with electricity
you commoned the ground/neutral between the inverters but they might not be designed with that in mind...
It's not weird you're not synced in phase... Or out of phase you have two separate 120 volt sources that are random. This is also alternating current you know that current travels on your neutral right? And the voltage reverses 60 times a second right? In other words the two sources are not independent when you combine the neutrals.
Would it save money on power bills to balance the usage on both sides of a power distribution panel? I heard the power company reads the highest side.
Would that not be the same as connecting to dual pole breaker like the one for your water heater which gives you 240 volts? I think So, but actually depending on your power sorces it will be like 2 single poles each giving you 120 = 240 volts