I'd definitely watch any video of yours, even if it's half an hour long, or even more! Your experience level and your talent to explain in an understandble way is truly excellent! You got my patreon support for sure. Thanks for all the effort you put into making such educational content.
As I've said before you have a talent for explaining things. I've been trying to properly understand real/apparent/reactive power for years but most explanations are shallow and don't really explain it well. I understood it fully within a couple of minutes of watching of this video. If you aren't a lecturer in electrical engineering it's a sad waste of your talent. I also think it is funny (and instructive) that you can explain things better with some scraps of paper and a couple of coloured pens than some people who are using fancy graphics and animations.
Yeah! I did understand how reactive power works before (even though, I didn't really know how the watt meters worked). But he is probably the first one I see, who is actually explaining how energy is stored on the way up the AC half wave, then released on the way down. Most others I have seen, are just focusing on the phase shift between voltage and current (often with calculations), without any real explanation how that phase shift appears. In my own case I figured it out (from others poor explanations, haha) by start looking at an ideal a capacitor and looking at the AC as varying DC with changing polarity, rather than AC. When a constant voltage (that doesn't change over time) is applied over a capacitor, no current will flow (easy to understand) - but as soon as the voltage are rising or falling over time, there will be current (is the voltage is rising, the capacitor will charge, if it's falling it will discharge). The quicker it rises or falls, the more current will flow. The steepest part of a sine wave (where voltage is changing the quickest over time) is right where it crosses zero and the flattest is the top of the waves (for a brief period, the voltage is constant and don't change over time). That's why current is at maximum when voltage is zero and there no current at all flowing when voltage is at maximum (thus creating an offset between voltage and current at 1/4 of a cycle or 90°). For an ideal inductor, the DC resistance is zero instead (which means there will always be a current if a voltage is applied, no matter how small - but the higher the voltage, the quicker the current will rise over time). This can be taught of as the current being the speed of a flywheel and the voltage a force applied to accelerate/decelerate that wheel. The current will be at maximum right at the zero crossing, where it have had maximum time to "accelerate". Once the polarity changes it will start decelerate and release energy, towards zero (which will happen right at the top of the wave) and then change direction and accelerate to maximum once the voltage is down to zero again, to then start decelerating again and so on. Now if a resistor (or other resistive load) is placed in series with the capacitor, there will be a voltage drop that prevents the capacitor voltage from exactly track the AC voltage - thus making the phase shift less than 90° and go more towards resistive than capacitive. Same for the inductor - it will be like putting a brake on the flywheel (or use it to drive something) in that example (mechanical work will be done instead of the wheel just accelerate back and forth)
@@Speeder84XL We did all this in high-school: were the technical stream would take you through electricity and electronics to a level sufficient to apprentice electrician, upon graduation. The U.S. Navy trained many sailors, just smarter than a bag of hammers, to have a good working knowledge of this stuff. If you were as smart as a bag of hammers, or not quite, you could always be in the U.S. Army. The U.S. Air Force was a lot pickier.
@@willthecat3861 And then there is always some asshole coming up with a comment like this. I just explained how I got it, like 15 years ago and taught it was (along with the explanation in the video) another good way to "visualize" the behaviour of the voltage/current and why the phase shift ends up at 90° for a pure inductive or capacitive load (and somewhere between 0-90 for a partially inductive/resistive or capacitive/resistive load). I'm not trying to outsmart anyone...
I teach this stuff to bewildered-looking engineering undergraduates, and this is quite the best description of how power factor works and can be measured, that I have seen. Aslo, that three-phase wattmeter is a miracle of mechanical design! I will be recommending this material to my students.
absolutely the BEST explanation of reactive and real power i've ever seen, thank you :) there are so many explanations out there that seem to leave me with more questions than I initially had, but your ability to explain things in such an intuitive way is just brilliant. thanks again and thank you for all your content.
"Who clicks on a video if it's half an hour long". Well, I do. And I do love all your videos irrespective of its duration. I learn a lot from them and appreciate your great effort. For this particular video, the explanation between 2:35 an 6:17 is one of the best one I've came across so far about this tricky subject. I've never learned it that way and now it makes sense. Thank you so much!
What a beautifully well made instruments! They must have been a huge investment to buy it when a new item! A credit to the designers & the assemblers of the time. The 3 phase mechanism is just incredible. Do not be concerned with length of your videos. You have a gift of being able to hold my attention & make a fantastic explanation, a true teacher! I must show my support for your channel as you deserve reward for your fantastic effort!
I never saw many of these old analog panel power meters; especially the 3-phase ones. I think they were expensive, so only used when there was a real good reason to know the average real power, and hence the electrical energy being consumed. Those Bakelite wattmeter "test sets," and associated shunts, were more common. And I've got one or two. We had them in the undergraduate motors and generators lab, and the utility company troubleshooters had them too.Not sure but, may commercial electricians might of had them too.
I will happily watch all of your videos, regardless of how long they are, because there is always so much to learn from you. Make the video as long as you feel it needs to be to convey the lesson. There are those of us that will only get more excited the longer your video is, due to the excellent way you explain everything. Thank you Dany! Fred
Thank you for showing these vintage analog power meters. Amazing internal mechanics, especially the 3-phase one. Nowadays, such meter would just contain 3 current-sensing coils, a silicon chip, some support components and a read-out. These mechanical ones are true pieces of workmanship and art.
Danyk, this is an example of great didactic skills! Congratulations on a wonderful video that helps preserve technology that, even if not current (no pun intended), Its analysis and understanding goes a long way into preparing good future enginners. Please preserve that collection of wonderful vintage devices. Spectacular!
I really loved it. The 3 phase wattmeter sound difficult, but it is really not. There is someone probably still alive sitting at home who have calibrated those. As we progress in the electronics, we loose how we made the simpler instruments. There is thousands of minds behind how to make a digital multimeter. From the silicone up and down and beyond. There is less minds behind how to make a analog simpler but yet precise and accurate, from metallurgi to the engineering. I think we need to have the knowledge to step back in the technology advancements. We need redundancy.
Great explanation 👍 by far the easiest to understand I've seen. I watch/listen to uploads 1:30+hrs long. 30mins is a short clip..... Kids today and their short attention spans.
This was a fantastic explanation of real vs. reactive power (as well as how watt meters work), and a video that was well worth watching. Even if it doesn't draw a ton of views due to its length, just know that your regular viewers really appreciated it.
Another absolutely superb and insightful video. For way too long I honestly had no clue about how wattmeters measured only real power (or even how they worked). Also a brilliant explanation on reactive vs real power
Danke! Thanks! Nice shown Nice explained Very good understandable for me. Special thanks for the warning of overload in low real Power but high active power operation
Very interesting, and what lovely instruments they are especially the three-phase wattmeter. Half an hour is definitely *not* a problem, when you get such a clear and understandable explanation of real power vs reactive power it is time well spent!
Me, I click your videos no matter how long. Its like having a personal tutor/friend in the room with me while I watch, listen and try to understand the mechanics behind what you show us :) I really appreciate your effort into your videos :) Thank you :) Děkuji :)
Thanks for the videos. I always wondered how these watt meters really work. The multiplication of voltage and current using a coil inside another coil is genius. Also this 3 phase meter is beautiful and genius. Would love to watch power factor meters video.
So cool that the panel meter uses a permanent magnet and aluminum plate for eddy current dampening! Early phonograph motors and kilowatt hour meters used that same technology although with AC electromagnets.
Thank you for your detailed and well illustrated explanation. Today I see only digital equipment, and the underlaying magnetic and electric forces are6not visible. Your video makes it visible and understandable in a great way..... I wish in my school times or university times we would have had someone like you as a teacher. Thank you.
Half hour video like this is enjoyable to watch, but then I was born loooong before the www arrived. :o) That 3 ph meter mechanism is just wonderful - who would (or could) make such a thing these days ? It must have been expensive back then, it would be priceless now. Thanks for the effort you put into making this video.
Hey, thanks for that bit of AC theory :) Builds upon EEVBlog's miniseries on AC, complex numbers etc. pretty nicely. The wattmeter teardown... I absolutely love it! These old meters are a damn marvel of technology, the build quality is superb although you really need to be careful not to drop one, otherwise it'll probably be done for. Thing of beauty, joy for ever. Which reminds me to make a '60s Polish UM-3a multimeter repair/teardown, haha :)
I enjoy the longer videos. your in depth explanation of all the components are great and I definitely learn a lot from your expansive knowledge..Thanks
I remember in my college electronics course we were taught a saying ELI the ICE man. E for voltage leads current in a purely inductive circuit and I (current) leads voltage in a capacitive circuit.
I recently did a repair on a Weston instruments variant of this. (damaged in shipping) the suspension on the meter needle and voltage coil was broken. needless to say, these are really hard to get back together once fully disassembled.
If you had a hand-cranked alternator feeding into a reactive load, would you be able to feel it getting stiffer over the parts where it is charging the capacitor or building up a field in the inductor, then easier to turn over the parts where the capacitor is discharging or the field is collapsing?
If I'm not mistaken the two springs that are used to return the needle to zero and supply the voltage coil are wound in opposite directions, in other words as one spring gets tighter the other gets looser. Edit. This is for the first wattmeter.
Correct me if I am wrong, but I think that the Watt meter needs spring return, so both springs should pull in the same direction. The cap/ind phase shift indicator shown at the end of the video do not have return spring if I remember correctly, the needle flaps around as you shake it and stops anywhere when not energized.
I have a 2000VA transformer made by CKD-Moradny in 1956. The transformer made me realize that Czechoslovakia is a very good transformer core maker, very advanced in metallurgy.
well, it depends on the definition of current direction. In this case, I call the current positive when it goes into the load and negative when it goes from the load back. This way it should be more intuitive, because people always say that inductive current is lagging the voltage and capacitive current is leading the voltage.
@@DiodeGoneWild Oh! Yes of course, the current direction can be also reversed. Thank you for clarifying that for me! The learned leading and lagging current for C and L was edged in my brain and got me confused.
Yes my friend, a wonderful job of explaining power factors and all without any of the maths. Who needs to know about vectors, imaginary numbers and the phase angle’s cosine? Not me :-) well done mate, keep up your good work and best of all, you lucky people, including old men like me :-) all get educated and it's all for free. PS my best regards to the co-star of your show, your wonderful cat, .
Another thing that this video has reminded me. I saw DGW's watt meter design way back when & promptly made a BOM & ordered multiples of components... as you do! And then completely & irresponsibly forgot about! So at my workbench there is a Digikey delivery pre covid that i opened & completely didn't recognize the parts that have therefore sat around & finally i now know what they're for. Idiot yes, but a neat wee project for this weekend i can say for certain....
I also noticed ... it looks like zinc, aluminium, tin or lead corrosion. Maybe the screws are aluminium or they are zinc plated. It's also on the damping magnet. Maybe it's also zinc plated, or maybe the aluminium oxidizes if it's an alnico magnet.
There 02:01 that's only with Vectors, or you can say: Apparent Pow = sqrt((Real Pow^2)+(Reactive Pow^2)) Or Apparent Pow = Real Pow + iReactive Pow [with complex numbers].
Nifty powerstrip Watt meter! Though, shouldn't the current shunt be placed before voltage sense circuit? As is, it measures the Voltage losses of the current shunt + the load connected. Personally I'd like to exclude the self consumption of current shunt from metering point of view when used as an investigatory tool. On the other hand, as-is it will correlate more closely with the house energy meter if the powerstrip is the only thing being "ON" in the house. Cracking good video for explaining reactive power to people, it is often quite a nebulos subject to understand.
Sir can you help me? To measure the amp coming from charge controller I used my multi meter in series but the amp it showing is only 1.3 amp. But the open circuit amp of charge controller is high. Does battery is interfering while measuring amp measurement from charge controller? Do I need to use shunt dc energy meter? I don’t have dc clamp meter. Please answer
Excellent video as usual! But to answer your question of "who is going to click on a video if it is half an hour long?" ME ME lol ...I wish they were longer! :)
Small question: is it possible to measure the reactive power consumed by supplying the voltage coil through a capacitor to shift the voltage by 90°? It deserves to be experienced.
I really like your long format videos! This one in particular was excellent, and featured one of the best explanations of power factor. Very clear, and easy to follow. I would be curious to see some distorted waveforms through the watt meters to see how accurate they are, maybe hook up some of the cheap SMPS you've explored in the past? And what about half wave rectification? Almost every range hood or range top microwave uses a diode to dim the lights on the bottom. It's effective, but seems like a bad idea to me; plus, it often makes the lights look flickery. Finding LED bulbs to fit in these lights is even harder 'cause the flicker is always very noticeable unless you get a good quality bulb. Bit of a tangent there~
Another great video. It’s fun how ancient electro mechanical technology can do what digital meters do with math. In effect these old watt meters are analog computers. I’m wondering when most public power utilities will start charging based on average current, aka VA, rather than watts. Most loads in homes with gas heating and cooking are non-linear loads. And that includes electric vehicle charging.
DGW what is the cord joining the three phase one made of? Is it thin wire? It is hard to imagine a 1960's natural or synthetic fibre cord that could withstand the wear and have no stretch (before kevlar).
I wondering why on the 3 phase simultaneous meter only the magnets and some screw heads have some kind of corrosion / crystals on them and not the rest of the metals. Is it due to material, the voltage difference between them or they react more with some particulate in the atmosphere due to their stronger magnetic fields? In my opinion the inductance of the coils can have an impact on the high frequency components of harmonically distorted currents so that their linearity changes with the waveform, the more closer to a sine the more accurate the reading. So I would not trust a meter that is not designed for high frequencies to correctly measure the power factor of a SMPS or other switching devices.
The wattmeter doesn't really see much of a high frequency when measuring the power input of a switching power supply. It only sees distorted 50Hz, which results in some harmonics (prime number multiples), mostly 3rd harmonic 150Hz, maybe 5th harmonic (250Hz). These are still low frequencies. But the meter with no iron core would probably be more accurate for this.
I was thinking of higher order harmonics, on badly distorted currents (light loads on smps, phase control in dimmers) but higher order harmonics carry little power so probably have a low impact in the power factor anyway. A simple frequency response characterization maybe using an audio amp and an audio signal generated by a pc, phone or scope would give an idea on how much impact the frequency has on these meters. Thanks for sharing your knowledge and your way of seeing electronics!
I just watched a video showing how oxygen is slightly magnetic (paramagnetic) so around magnetized parts the concertation can be a little higher. This partially explains why there is more corrosion on magnetic parts. So probably there are other paramagnetic and corrosive substances that can be are attracted.
Does a power factor make sense when it comes to harmonical distortion of current? I mean. If I measure input of a FULLBRIDGE RECTIFIER loaded by some capacitive load, there is voltage before the current in the first quarter of the period, so it behaves like an inductor, but in the second quarter there goes voltage after the current, which is typical for capacitor. So it is capacitive or inductive load? On the other hand. There is some Uef of the harmonic voltage source, there is Ief of the current flowing into that load and there is effective power burning on that load. You can multiply the effective voltage with the effective current and compare it to effective power and if you get result between , then you can compute the φ from (PF)=cos(φ) equation. They are just numbers, that φ would be also just a number, which has nothing to do with that phase shifting things. Because the current is not the harmonic signal. Going deeper. The whole concept of frequency and phase is widely misunderstood. In fact there is nothing like power factor and things like that, it is a product of mathematical transformations, which requires some conditions to be met. On top of that all, interpreting their results could be a little bit tricky. In fact, p(t)=u(t)·i(t).When the load is made by resistor, where current is proportional to the voltage, then i(t)=щ·u(t), let щ=1/R (just to get something widely known), so i(t)=u(t)/R, and then p(t)=(u(t))²/R. IF the u(t) is harmonic signal, like u(t)=U·sin(ωt), then you result with something like p(t)=(U·sin(ωt))²=U²·sin²(ωt). To compare the long term effects with direct current (where u(t) is konstant, let u(t)=Uef, which leads to i(t)=u(t)/R=Uef/R, so p(t)=Uef·(Uef/R)=(Uef)²/R which is also constant, so let p(t)=Pef=(Uef)²/R) you have to integrate it over some period to obtain Work, this is where the √2 between amplitude and rms voltage/current comes from etc., I don't want to summon the whole math here. When it comes e.g. to capacitor used as a load, then the current is proportional to the first derivation of voltage over time, so i(t)=щ·(d(u(t))/dt), so IF the u(t) is harmonic signal u(t)=U·sin(ωt), so i(t)=щ·U·cos(ωt)=щ·U·sin(ωt-(π/4)), which then leads to slightly different results when integrating p(t). More important is, that this is where the phase shifting comes from. This is not the feature of the capacitor, this is the feature of the first derivation of the sin(x), which is cos(x), which is nothing more then a phase shifted sinus. Similar things happens when it comes to inductor, where the voltage is proportional to time derivation of current, which is similar to statement: current is proportional to time integration of voltage, which also leads to phase shifted harmonic function. So why is this so important when this is tight to linear part, harmonic signals and capacitive/inductive loads? This is due to fact, that most parts are in fact in some part of their operational region linear, capacitive or reactive, harmonic signals are common and on top of that all, any signal could be transformed to finite or infinite sum of harmonic signals, so you can analyse your circuit on every of them and then stitch that results together, which is typically much easier than doing that calculations in time domain. But if the i(t) is non-harmonic signal despite the fact, that u(t) is, which is exactly what happens at that FULLBRIDGE RECTIFIER, then you can transform this to (probably infinite) set of harmonics, where each of them would have its own frequency and phase shift etc. But in this particular case is much easier to make computations in time domain. This is what sometimes happens.
No. The frequency is too high in the upper octaves, so the inductance will roll off the signal. Maybe for subwoofer only. But the current coil impedance will also be too high I'd say.
@@ingenfestbrems Not sure. Coil max. current rating, DC resistance and inductance, as well as impedance of the speaker and power rating of the amp need to be taken into account. It would be much better to use the multiplier IC and a very low resistance current sensing resistor honestly. You could still technically connect it to an analog readout, for example by driving it with a small power amp (like LM386 at low gain) and a diode in series to the meter.
@@ingenfestbrems The problem with most of the electromechanical meters is they are designed for a specific frequency and voltage (mains) where the current per watt is very low compared to a speaker output where voltage is low and current is very high. If you have a meter which can handle low voltage and high current (current coil is low resistance) it might work but it's still not the best solution. When using ICs or other active curcuitry on the other hand, you can tune the curcuit to the specific task and it'll work without causing much change to frequency response and damping factor if you can do it correctly.
As usual excellent content. I really need to buy an analog meter. Also I need to get a vacuum tube voltmeter, saw on a Mr Carlson video how amazing some of their input impedances are.
I clicked on the video and watched it from the start to finish. Very interesting. Never seen mechanical watt meters. And the three phase one. Man that is some mechanical engineering if you ask me. You should mention the needle counterweights on the voltage coil sticking up from it into the space. Someone may ask what they are and what they do. I send you an email by the way. Want to buy some programed ATMEGA from you. I can not get my USBASP programer working on Win 10. And my current PC doesnt have paralel port to use PonyProg... It sucks...
I'd definitely watch any video of yours, even if it's half an hour long, or even more! Your experience level and your talent to explain in an understandble way is truly excellent! You got my patreon support for sure. Thanks for all the effort you put into making such educational content.
I would do the same, easily. Love the long content with more room for extra explanations and examples. Keep it up, DGW.
OUTSTANDING
I couldn't have said it better myself!
As I've said before you have a talent for explaining things. I've been trying to properly understand real/apparent/reactive power for years but most explanations are shallow and don't really explain it well. I understood it fully within a couple of minutes of watching of this video. If you aren't a lecturer in electrical engineering it's a sad waste of your talent.
I also think it is funny (and instructive) that you can explain things better with some scraps of paper and a couple of coloured pens than some people who are using fancy graphics and animations.
Yeah!
I did understand how reactive power works before (even though, I didn't really know how the watt meters worked). But he is probably the first one I see, who is actually explaining how energy is stored on the way up the AC half wave, then released on the way down. Most others I have seen, are just focusing on the phase shift between voltage and current (often with calculations), without any real explanation how that phase shift appears.
In my own case I figured it out (from others poor explanations, haha) by start looking at an ideal a capacitor and looking at the AC as varying DC with changing polarity, rather than AC. When a constant voltage (that doesn't change over time) is applied over a capacitor, no current will flow (easy to understand) - but as soon as the voltage are rising or falling over time, there will be current (is the voltage is rising, the capacitor will charge, if it's falling it will discharge). The quicker it rises or falls, the more current will flow.
The steepest part of a sine wave (where voltage is changing the quickest over time) is right where it crosses zero and the flattest is the top of the waves (for a brief period, the voltage is constant and don't change over time). That's why current is at maximum when voltage is zero and there no current at all flowing when voltage is at maximum (thus creating an offset between voltage and current at 1/4 of a cycle or 90°).
For an ideal inductor, the DC resistance is zero instead (which means there will always be a current if a voltage is applied, no matter how small - but the higher the voltage, the quicker the current will rise over time). This can be taught of as the current being the speed of a flywheel and the voltage a force applied to accelerate/decelerate that wheel.
The current will be at maximum right at the zero crossing, where it have had maximum time to "accelerate". Once the polarity changes it will start decelerate and release energy, towards zero (which will happen right at the top of the wave) and then change direction and accelerate to maximum once the voltage is down to zero again, to then start decelerating again and so on.
Now if a resistor (or other resistive load) is placed in series with the capacitor, there will be a voltage drop that prevents the capacitor voltage from exactly track the AC voltage - thus making the phase shift less than 90° and go more towards resistive than capacitive.
Same for the inductor - it will be like putting a brake on the flywheel (or use it to drive something) in that example (mechanical work will be done instead of the wheel just accelerate back and forth)
@@Speeder84XL We did all this in high-school: were the technical stream would take you through electricity and electronics to a level sufficient to apprentice electrician, upon graduation. The U.S. Navy trained many sailors, just smarter than a bag of hammers, to have a good working knowledge of this stuff. If you were as smart as a bag of hammers, or not quite, you could always be in the U.S. Army. The U.S. Air Force was a lot pickier.
@@willthecat3861 And then there is always some asshole coming up with a comment like this.
I just explained how I got it, like 15 years ago and taught it was (along with the explanation in the video) another good way to "visualize" the behaviour of the voltage/current and why the phase shift ends up at 90° for a pure inductive or capacitive load (and somewhere between 0-90 for a partially inductive/resistive or capacitive/resistive load). I'm not trying to outsmart anyone...
I teach this stuff to bewildered-looking engineering undergraduates, and this is quite the best description of how power factor works and can be measured, that I have seen. Aslo, that three-phase wattmeter is a miracle of mechanical design! I will be recommending this material to my students.
absolutely the BEST explanation of reactive and real power i've ever seen, thank you :) there are so many explanations out there that seem to leave me with more questions than I initially had, but your ability to explain things in such an intuitive way is just brilliant. thanks again and thank you for all your content.
Wow that has to be the best explanation of reactive vs real power. Simple and easy to understand.
Yeah, he explained it very well and in a very understandable way. It even made it through my thick head.
"Who clicks on a video if it's half an hour long". Well, I do. And I do love all your videos irrespective of its duration. I learn a lot from them and appreciate your great effort.
For this particular video, the explanation between 2:35 an 6:17 is one of the best one I've came across so far about this tricky subject. I've never learned it that way and now it makes sense. Thank you so much!
What a beautifully well made instruments! They must have been a huge investment to buy it when a new item! A credit to the designers & the assemblers of the time. The 3 phase mechanism is just incredible. Do not be concerned with length of your videos. You have a gift of being able to hold my attention & make a fantastic explanation, a true teacher! I must show my support for your channel as you deserve reward for your fantastic effort!
I never saw many of these old analog panel power meters; especially the 3-phase ones. I think they were expensive, so only used when there was a real good reason to know the average real power, and hence the electrical energy being consumed. Those Bakelite wattmeter "test sets," and associated shunts, were more common. And I've got one or two. We had them in the undergraduate motors and generators lab, and the utility company troubleshooters had them too.Not sure but, may commercial electricians might of had them too.
@@willthecat3861 yeah and ive seen these laying around in the old abandoned factories around here guess they really think they are worthless now
Yet another example of why this is such a great channel for learning.
wow I have never seen any other youtuber being so precise in explanation of electronics or any other field.Wow you must be really good😃
We are so lucky to have a great teacher like Danyk.
I will happily watch all of your videos, regardless of how long they are, because there is always so much to learn from you. Make the video as long as you feel it needs to be to convey the lesson. There are those of us that will only get more excited the longer your video is, due to the excellent way you explain everything. Thank you Dany! Fred
Holy crap this video is so informative. I've never understood this topic so well.
Every second of it is pure gold!
This is probably the best video explaining what a power factor is and why. Highly recommended. Danyk, great work!
Never really understood the sorcery of Apparent & Real Power but you sir described it all pretty well. Thanks a ton!
This was an excellent deep dive into a fascinating old-school technology. Thanks for putting in the effort.
Man!! Can't get enough of you videos. Excellent explanation of theories. Million times interesting!!
Thank you for showing these vintage analog power meters. Amazing internal mechanics, especially the 3-phase one.
Nowadays, such meter would just contain 3 current-sensing coils, a silicon chip, some support components and a read-out. These mechanical ones are true pieces of workmanship and art.
Danyk, this is an example of great didactic skills! Congratulations on a wonderful video that helps preserve technology that, even if not current (no pun intended), Its analysis and understanding goes a long way into preparing good future enginners. Please preserve that collection of wonderful vintage devices. Spectacular!
I really loved it. The 3 phase wattmeter sound difficult, but it is really not. There is someone probably still alive sitting at home who have calibrated those.
As we progress in the electronics, we loose how we made the simpler instruments. There is thousands of minds behind how to make a digital multimeter. From the silicone up and down and beyond.
There is less minds behind how to make a analog simpler but yet precise and accurate, from metallurgi to the engineering.
I think we need to have the knowledge to step back in the technology advancements. We need redundancy.
The three-phase wattmeter has an absolutely mesmerizing mechanism. Wonderful mechanical construction. Genius.
Great explanation 👍 by far the easiest to understand I've seen.
I watch/listen to uploads 1:30+hrs long. 30mins is a short clip..... Kids today and their short attention spans.
Wow, I never thought it could be possible to build such a thing so easy for real power. Great explanation!
This was a fantastic explanation of real vs. reactive power (as well as how watt meters work), and a video that was well worth watching. Even if it doesn't draw a ton of views due to its length, just know that your regular viewers really appreciated it.
Videos like this are exactly why I support you on Patreon.
And that 3-phase meter must have been outrageously expensive when it was new.
Another absolutely superb and insightful video. For way too long I honestly had no clue about how wattmeters measured only real power (or even how they worked). Also a brilliant explanation on reactive vs real power
I like the "bloody long" videos, Danyk - please keep doing these great videos :)
Danke! Thanks!
Nice shown
Nice explained
Very good understandable for me.
Special thanks for the warning of overload in low real Power but high active power operation
as normal you give us a load of class info. THANK YOU D, YOU NEVER FAIL TO IMPRESS...
Nice video! I really like the peek inside the 3 phase mechanical meter 👍🏻 Thank you.
Very interesting, and what lovely instruments they are especially the three-phase wattmeter. Half an hour is definitely *not* a problem, when you get such a clear and understandable explanation of real power vs reactive power it is time well spent!
Me, I click your videos no matter how long. Its like having a personal tutor/friend in the room with me while I watch, listen and try to understand the mechanics behind what you show us :) I really appreciate your effort into your videos :) Thank you :) Děkuji :)
Thanks for the videos. I always wondered how these watt meters really work. The multiplication of voltage and current using a coil inside another coil is genius. Also this 3 phase meter is beautiful and genius.
Would love to watch power factor meters video.
This was definitely worth 30 min of my time.
Very good video as always.
Immerwieder gut erklärt.Die alte Technik ist auch immer sehr schön anzusehen, außerdem ergibt sich aus den mechanischen Meisterwerken die Funktion.
I learn more from diode gone wild than anywhere else. you are awesome...thanks for all the great videos
The people who designed this mechanical stuff to measure power are the real smart ones !....cheers.
Great video.
I love the complexity of the 3ø power meter.
AC theory is always a great review for electronics. Good job covering this. Phasor review is mandatory.
I always expected your video more than 20min long. ❤️
30:10 I might not understand completely the details of schematic drawing but I watched it completely. I like the way you explain it. 🙂
So cool that the panel meter uses a permanent magnet and aluminum plate for eddy current dampening! Early phonograph motors and kilowatt hour meters used that same technology although with AC electromagnets.
Thank you for your detailed and well illustrated explanation. Today I see only digital equipment, and the underlaying magnetic and electric forces are6not visible. Your video makes it visible and understandable in a great way..... I wish in my school times or university times we would have had someone like you as a teacher. Thank you.
Half hour video like this is enjoyable to watch, but then I was born loooong before the www arrived. :o)
That 3 ph meter mechanism is just wonderful - who would (or could) make such a thing these days ?
It must have been expensive back then, it would be priceless now.
Thanks for the effort you put into making this video.
THIS IS EXACTLY THE VIDEO I'VE WAITING FOR! Thanks!! ♥️
Very very interesting! I was astonished about the 3 phases watmeter mecanic system! Your explanations are very good. Thank you a lot.
Very nice old meters! Thanks for posting this one, very good explanation.
Excellent video, I learn something new every time.
Hey, thanks for that bit of AC theory :) Builds upon EEVBlog's miniseries on AC, complex numbers etc. pretty nicely.
The wattmeter teardown... I absolutely love it! These old meters are a damn marvel of technology, the build quality is superb although you really need to be careful not to drop one, otherwise it'll probably be done for. Thing of beauty, joy for ever. Which reminds me to make a '60s Polish UM-3a multimeter repair/teardown, haha :)
I enjoy the longer videos. your in depth explanation of all the components are great and I definitely learn a lot from your expansive knowledge..Thanks
Fan from India ❤️
I remember in my college electronics course we were taught a saying ELI the ICE man. E for voltage leads current in a purely inductive circuit and I (current) leads voltage in a capacitive circuit.
after two years of waiting we finally got our videoo
I recently did a repair on a Weston instruments variant of this. (damaged in shipping) the suspension on the meter needle and voltage coil was broken. needless to say, these are really hard to get back together once fully disassembled.
Another great explanation. Thank you Dany. God bless you!!
Even though the video was 30 minutes long I never get bored
If you had a hand-cranked alternator feeding into a reactive load, would you be able to feel it getting stiffer over the parts where it is charging the capacitor or building up a field in the inductor, then easier to turn over the parts where the capacitor is discharging or the field is collapsing?
If I'm not mistaken the two springs that are used to return the needle to zero and supply the voltage coil are wound in opposite directions, in other words as one spring gets tighter the other gets looser.
Edit. This is for the first wattmeter.
Correct me if I am wrong, but I think that the Watt meter needs spring return, so both springs should pull in the same direction. The cap/ind phase shift indicator shown at the end of the video do not have return spring if I remember correctly, the needle flaps around as you shake it and stops anywhere when not energized.
Nice to know more about power factor and different types of loads. Than you!
I finally understand why PC UPSs, and generators, state VA ratings and not W, after learning about pure and apparent powers
I have a 2000VA transformer made by CKD-Moradny in 1956. The transformer made me realize that Czechoslovakia is a very good transformer core maker, very advanced in metallurgy.
You're brilliant! Looking for another great videos! Electric/electronic measurement devices are very interesting! Thank you!
2:36 It is possible that the phase shift is the other way around for inductance and capacitance? I´m realy unsure....
well, it depends on the definition of current direction. In this case, I call the current positive when it goes into the load and negative when it goes from the load back. This way it should be more intuitive, because people always say that inductive current is lagging the voltage and capacitive current is leading the voltage.
@@DiodeGoneWild Oh! Yes of course, the current direction can be also reversed. Thank you for clarifying that for me! The learned leading and lagging current for C and L was edged in my brain and got me confused.
Yes my friend, a wonderful job of explaining power factors and all without any of the maths.
Who needs to know about vectors, imaginary numbers and the phase angle’s cosine? Not me :-) well done mate, keep up your good work and best of all, you lucky people, including old men like me :-) all get educated and it's all for free.
PS my best regards to the co-star of your show, your wonderful cat, .
Another thing that this video has reminded me. I saw DGW's watt meter design way back when & promptly made a BOM & ordered multiples of components... as you do! And then completely & irresponsibly forgot about! So at my workbench there is a Digikey delivery pre covid that i opened & completely didn't recognize the parts that have therefore sat around & finally i now know what they're for. Idiot yes, but a neat wee project for this weekend i can say for certain....
Thanks, master. 29:05 What's that salt-like material on the screws?
I also noticed ... it looks like zinc, aluminium, tin or lead corrosion. Maybe the screws are aluminium or they are zinc plated. It's also on the damping magnet. Maybe it's also zinc plated, or maybe the aluminium oxidizes if it's an alnico magnet.
Great video thank you for the effort, greetings from Bulgaria
Impressive that these wattmeters are still pretty accurate after all those years. Any datecode on them? I would guess mid to late 60s.
More like early 50s but they're eastern bloc so they might be later.
There 02:01 that's only with Vectors, or you can say:
Apparent Pow = sqrt((Real Pow^2)+(Reactive Pow^2))
Or
Apparent Pow = Real Pow + iReactive Pow [with complex numbers].
Very nice, i like the 3 phase mechanical meter. 👌🏻
Nifty powerstrip Watt meter! Though, shouldn't the current shunt be placed before voltage sense circuit? As is, it measures the Voltage losses of the current shunt + the load connected. Personally I'd like to exclude the self consumption of current shunt from metering point of view when used as an investigatory tool.
On the other hand, as-is it will correlate more closely with the house energy meter if the powerstrip is the only thing being "ON" in the house.
Cracking good video for explaining reactive power to people, it is often quite a nebulos subject to understand.
woooooow that three phase one is insane!
Awesome video!
Really interesting to know how AC watt meters deal with reactive power (I didn't really know that before)
Sir can you help me? To measure the amp coming from charge controller I used my multi meter in series but the amp it showing is only 1.3 amp. But the open circuit amp of charge controller is high. Does battery is interfering while measuring amp measurement from charge controller? Do I need to use shunt dc energy meter? I don’t have dc clamp meter. Please answer
Great explanation 👍
Thanks for sharing ☺️
I thought I was pretty good at following people with a heavy accent, but this takes the cake. The video really needs captions.
Excellent video as usual! But to answer your question of "who is going to click on a video if it is half an hour long?" ME ME lol ...I wish they were longer! :)
Can someone explain why devices with rectifiers only draw current at the peak of the sine wave? Because of the following smoothing caps?
Small question: is it possible to measure the reactive power consumed by supplying the voltage coil through a capacitor to shift the voltage by 90°?
It deserves to be experienced.
I really like your long format videos! This one in particular was excellent, and featured one of the best explanations of power factor. Very clear, and easy to follow. I would be curious to see some distorted waveforms through the watt meters to see how accurate they are, maybe hook up some of the cheap SMPS you've explored in the past? And what about half wave rectification? Almost every range hood or range top microwave uses a diode to dim the lights on the bottom. It's effective, but seems like a bad idea to me; plus, it often makes the lights look flickery. Finding LED bulbs to fit in these lights is even harder 'cause the flicker is always very noticeable unless you get a good quality bulb. Bit of a tangent there~
There is often a resistir parallel to the current coil.
Another great video. It’s fun how ancient electro mechanical technology can do what digital meters do with math. In effect these old watt meters are analog computers. I’m wondering when most public power utilities will start charging based on average current, aka VA, rather than watts. Most loads in homes with gas heating and cooking are non-linear loads. And that includes electric vehicle charging.
DGW what is the cord joining the three phase one made of? Is it thin wire? It is hard to imagine a 1960's natural or synthetic fibre cord that could withstand the wear and have no stretch (before kevlar).
Very instructive video.
Great video, up there with your others that cover strings reactive phrases & rotational dynamics.
But better than the 'ants' video.
briljant explanation - thank you !
Made in Czechoslovakia! So much precision but it still challenges the engineer!
I like long videos, prefer them to short ones
Wat Programm are you using to draw the schematics ?
No program, it's a DGW digital process.
I would love the videos to be bloodier or longer!
I think that the longer videos need proportionally increase Cat exposure.
very very very very good video ! thanks
I wondering why on the 3 phase simultaneous meter only the magnets and some screw heads have some kind of corrosion / crystals on them and not the rest of the metals. Is it due to material, the voltage difference between them or they react more with some particulate in the atmosphere due to their stronger magnetic fields?
In my opinion the inductance of the coils can have an impact on the high frequency components of harmonically distorted currents so that their linearity changes with the waveform, the more closer to a sine the more accurate the reading. So I would not trust a meter that is not designed for high frequencies to correctly measure the power factor of a SMPS or other switching devices.
The wattmeter doesn't really see much of a high frequency when measuring the power input of a switching power supply. It only sees distorted 50Hz, which results in some harmonics (prime number multiples), mostly 3rd harmonic 150Hz, maybe 5th harmonic (250Hz). These are still low frequencies. But the meter with no iron core would probably be more accurate for this.
I was thinking of higher order harmonics, on badly distorted currents (light loads on smps, phase control in dimmers) but higher order harmonics carry little power so probably have a low impact in the power factor anyway. A simple frequency response characterization maybe using an audio amp and an audio signal generated by a pc, phone or scope would give an idea on how much impact the frequency has on these meters. Thanks for sharing your knowledge and your way of seeing electronics!
I just watched a video showing how oxygen is slightly magnetic (paramagnetic) so around magnetized parts the concertation can be a little higher. This partially explains why there is more corrosion on magnetic parts. So probably there are other paramagnetic and corrosive substances that can be are attracted.
Does a power factor make sense when it comes to harmonical distortion of current? I mean. If I measure input of a FULLBRIDGE RECTIFIER loaded by some capacitive load, there is voltage before the current in the first quarter of the period, so it behaves like an inductor, but in the second quarter there goes voltage after the current, which is typical for capacitor. So it is capacitive or inductive load? On the other hand. There is some Uef of the harmonic voltage source, there is Ief of the current flowing into that load and there is effective power burning on that load. You can multiply the effective voltage with the effective current and compare it to effective power and if you get result between , then you can compute the φ from (PF)=cos(φ) equation. They are just numbers, that φ would be also just a number, which has nothing to do with that phase shifting things. Because the current is not the harmonic signal.
Going deeper. The whole concept of frequency and phase is widely misunderstood. In fact there is nothing like power factor and things like that, it is a product of mathematical transformations, which requires some conditions to be met. On top of that all, interpreting their results could be a little bit tricky.
In fact, p(t)=u(t)·i(t).When the load is made by resistor, where current is proportional to the voltage, then i(t)=щ·u(t), let щ=1/R (just to get something widely known), so i(t)=u(t)/R, and then p(t)=(u(t))²/R. IF the u(t) is harmonic signal, like u(t)=U·sin(ωt), then you result with something like p(t)=(U·sin(ωt))²=U²·sin²(ωt). To compare the long term effects with direct current (where u(t) is konstant, let u(t)=Uef, which leads to i(t)=u(t)/R=Uef/R, so p(t)=Uef·(Uef/R)=(Uef)²/R which is also constant, so let p(t)=Pef=(Uef)²/R) you have to integrate it over some period to obtain Work, this is where the √2 between amplitude and rms voltage/current comes from etc., I don't want to summon the whole math here. When it comes e.g. to capacitor used as a load, then the current is proportional to the first derivation of voltage over time, so i(t)=щ·(d(u(t))/dt), so IF the u(t) is harmonic signal u(t)=U·sin(ωt), so i(t)=щ·U·cos(ωt)=щ·U·sin(ωt-(π/4)), which then leads to slightly different results when integrating p(t). More important is, that this is where the phase shifting comes from. This is not the feature of the capacitor, this is the feature of the first derivation of the sin(x), which is cos(x), which is nothing more then a phase shifted sinus. Similar things happens when it comes to inductor, where the voltage is proportional to time derivation of current, which is similar to statement: current is proportional to time integration of voltage, which also leads to phase shifted harmonic function.
So why is this so important when this is tight to linear part, harmonic signals and capacitive/inductive loads? This is due to fact, that most parts are in fact in some part of their operational region linear, capacitive or reactive, harmonic signals are common and on top of that all, any signal could be transformed to finite or infinite sum of harmonic signals, so you can analyse your circuit on every of them and then stitch that results together, which is typically much easier than doing that calculations in time domain.
But if the i(t) is non-harmonic signal despite the fact, that u(t) is, which is exactly what happens at that FULLBRIDGE RECTIFIER, then you can transform this to (probably infinite) set of harmonics, where each of them would have its own frequency and phase shift etc. But in this particular case is much easier to make computations in time domain. This is what sometimes happens.
Great video. Thank you
Could it be used to measure watts on a audio amplifier?
No. The frequency is too high in the upper octaves, so the inductance will roll off the signal. Maybe for subwoofer only. But the current coil impedance will also be too high I'd say.
@@westelaudio943 so giving it a 40hz signal it could
@@ingenfestbrems
Not sure. Coil max. current rating, DC resistance and inductance, as well as impedance of the speaker and power rating of the amp need to be taken into account.
It would be much better to use the multiplier IC and a very low resistance current sensing resistor honestly. You could still technically connect it to an analog readout, for example by driving it with a small power amp (like LM386 at low gain) and a diode in series to the meter.
@@ingenfestbrems
The problem with most of the electromechanical meters is they are designed for a specific frequency and voltage (mains) where the current per watt is very low compared to a speaker output where voltage is low and current is very high.
If you have a meter which can handle low voltage and high current (current coil is low resistance) it might work but it's still not the best solution.
When using ICs or other active curcuitry on the other hand, you can tune the curcuit to the specific task and it'll work without causing much change to frequency response and damping factor if you can do it correctly.
I click on long videos. When the video is interesting and/or educational then the time just evaporates.
those ad633 are expensive. needed one to build a ring modulator and the chip was around 20 dollars. interesting chip though.
As usual excellent content. I really need to buy an analog meter. Also I need to get a vacuum tube voltmeter, saw on a Mr Carlson video how amazing some of their input impedances are.
10 Megaohm......und mehr.
I like your video. I appreciate long video than short once like 10 mins...
I clicked on the video and watched it from the start to finish. Very interesting. Never seen mechanical watt meters. And the three phase one. Man that is some mechanical engineering if you ask me. You should mention the needle counterweights on the voltage coil sticking up from it into the space. Someone may ask what they are and what they do. I send you an email by the way. Want to buy some programed ATMEGA from you. I can not get my USBASP programer working on Win 10. And my current PC doesnt have paralel port to use PonyProg... It sucks...
I like your long videos👍