Grew up in My Dads electric motor repair shop. we stripped out old motors and re used most parts back in the 1970s. one of my jobs was to charge each capacitor with 110vac and then discharge with a screwdriver just as you did there. throw out the bad ones. Also, point the terminal end away from you when energizing because they can explode and blow out at the top
Thanks for doing this video. It had been awhile since I checked capacitors and this brought it all bad. My run capacitor is bad. Simple enough to get a new one and a lot cheaper than a new motor.
When you do the Ohms test, the results you get are due to the following. The capacitor initially takes a charge and therefore shows what is in effect a current reading. When the capacitor reaches the voltage of the internal battery in the meter, the capacitor will be 'fully charged' (as far as that test set up is concerned) then no more current will flow into it and it will show an open circuit (or OL which is not really Overload). It is worth keeping the meter (set to a high resistance range) on the capacitor to see if there is a measurable resistance. This will indicate a capacitor with a poor insulation resistance and which will therefore not hold its charge. The snag with this test is that it is done at about 1 1/2 volts which doesn't stress the capacitor at all. The mains voltage charge/discharge test will only work some of the time even with a good capacitor. If the cap is disconnected from the mains supply at just that moment when the mains voltage passes through zero (it is AC), there will be no charge remaining in the cap. Indeed the size of spark you get will vary according to the moment when the cap is disconnected from the mains. If this mains test is done with a failed capacitor (short circuit in the cap) the results will be fairly spectacular. Take care!
@@RRaucinathank you for this tidbit of info that just solved my problem. The vent hole being blown out. I saw this on my capacitor but did not realize it was an indication of failure. Thanks again.
Great video. I've watched so many just trying to figure out how to test a capacitor attached to the relay of my lg fridge compressor. Even took it to couple of stores. One said it was good the other...it was bad. So confused. Your deliverance of the test method is the best so far. Thank you and God bless you. If you can also do a video on how to test start relays for a fridge that would be great....that's the next thing I have to figure out.
Thanks for the explanation. I have a 10hp single phase Leeson compressor motor that stopped today, and started buzzing. I'm going to test the caps first.
Very helpful, the capacitor was the problem, had another capacitor off an engine that was sitting in the garage and it tested fine, engine now runs like it should.
I have several meters from top end to crap and I only recently discovered that one or two of them has a capacitor test setting. I had always used the resistance test, needle up and then back to zero. Feeling a bit stupid on that! In my defense, on retesting a bunch of caps judged good by using resistance, the true cap test agreed. Seems like most caps are either dead or good with little in between - especially start caps that usually blow their top.
Nice video. Good thing you didn’t show that part with the 120 v.a.c. cord and screwdriver! LOL. I am a retired electrician and when done safely, electricity is really cool to mess with.
Love the cajones to show this, good video for the ignorant but smart not stupid people. Personally I'm not touching the second test but itwas very informative to see it work.
My wife had her friends over for a party while I was gone and someone stole my Fluke meter, When I complained she blamed me, I divorced her and recently picked up a mint Fluke meter at a garage sale for 20 bucks, Win Win!
Wives ughhh... I went away for a weekend, and my wife told me she was going to have a garage sale while I was gone. Awhile later I was complaining that I couldn't find my Fluke meter. It turns out she sold it at her garage sale for 20 bucks. She blamed me, saying I never told her she couldn't sell it, or not to sell it. I divorced her
@@junkyardwizard9092 Thats crazy! my wife went to a party a little bit ago and when she got home she said she got me a gift. To my surprise it was a beautiful fluke meter. I guess marriage isn't the same for everyone
Hell yeah I've learned capitance.... again..... This time I will remember exactly how to do it on my 87,all the way till time to check my air compressor kicking the the breaker, see ya again then Chris
Just a quick note Make sure when discharging the capacitor that you are using an electrically rated insulated screwdriver !! Like the one he is using ...other wise it could jump through the handle
1. Never discharge with a screw driver. Put your meter on DC put your test leads on the capacitor and it will drain it, that is the proper and safe way. 2. Put your meter on ohm's and your 9 volt battery in the meter will start to charge the capacitor if's it's good you will see the values going up rather fast depending on the charge of your battery. If it does not go up fast it's bad. I would suggest a stand lone tester the Supco MFD10 capacitor tester if you repair shit from time to time. Or a meter like the field piece SC640 which has the MFD option if your always working you can have one tool that does it all.
you seem to be a service tech who was taught by his daddy or uncle. I remember when i was trying to learn about motor caps and how to test them. I went to a bunch of appliance and motor parts stores and tried to ask how to test caps. no body was giving it up. they either did not know or understood the value of that information. It took me a while but I finally learned how to test them and understood the value of that information too. that knowledge helped me pay my rent and foot many many time over. And you know, if a customer knows hows and whys of a breakdown you won't get the service call. it blows my mind to think why people would devalue their knowledge. the only reason you make 80 to 200 or more per hour is because of what you know. but when you give it away it is worth nothing.
Jack I understand your thought process here, but believe me when I say this. 99 percent of people are shit scared of electric, and you could show them every trick in the book, and they still would not try it. So chill man 🙂
Thanks. FYI: @2:55, that's not a "u"; it's a lower-case Greek letter "mu", which stands for micro. (Mu has tails that go down below the "u" on both sides, longer on the left.)
I've found readings on my ESR meter often give different results compared to simple capacitance testing with a multimeter, the two testing devices are complementary. Presumably that unreliability of a single test is one of the reasons HVAC techs simply replace the run/start cap when fixing or replacing motors. No test is perfect.
Thanks to this video i found the capacitor test function on my multimeter. I was confused as it is such an expensive Fluke multimeter, that there wouldn’t be a capacitor test function on it 😂 Just didn’t recognise the symbol for it. Confirmed that my start capacitor is bad & ordered a new one already 🙂 I found a water well in my backyard of which the motor doesn’t start, the motor only hums, i hope it works after replacing the start cap.
If the cap is disconnected from everything, the current will not flow to ground. It flows from one cap terminal to the other so it doesn't really matter if you're on concrete or not. The cap can still be very dangerous. You must discharge it before touching it with your hands or meters. A BIG TRICK is to discharge the capacitor like the book says; leave it laying on the bench and come back a little later, maybe a day later, and it will still knock you on your ass. A big capacitor does not loose all it's energy with a single quick short circuit. Short it every time before you handle the cap.
@blackrockcity The light bulb thing makes sense... Does the bulb type matter? Can it be just a 12v automotive bulb, or have to be say a 120v bulb, and if so does the bulb wattage matter at all?
Very informative video. need to get a fluke meter it's a must have to diagnose electric systems. Thanks for sharing you are clear in your safety warnings but I wonder how many will find out the hard way concerning discharging the capacitor before testing it.
Frank W Regarding the amount functions maybe. It’s stupid to think that a 200 euro Fluke is the same league as a 30$ unknown brand. That’s like saying a Ferrari is the same as a Lada because they both have a steering wheel pedals and a gear shifter.
@@Engineer9736 I guess if one was going to race every weekend a Ferrari would be fine but if one needed a ride home once or twice then a Yugo would do the job.
@@gfinklea You are paying for the safety provided by a good quality meter. You can get accurate enough readings and a similar amount of functions from cheaper meters, but you risk your own life on the shitty build quality and inappropriate fuses of the cheap meters.
Very nice and informative, it would be helpful also to comment on the other ends of the testing probes as to which location they should be plugged into....Thank You
I'm trying to test the caps on an air compressor. One of the caps have resistors soldered into the terminals. Would those resistors cause the uf numbers to be excessively high and out of spec? the other cap is the same model and tests within range, but again doesn't have the resistors. Thanks for the video.
i"m surprised you didn't show the most accurate test, while the cap is in circuit and energized. Use a clamp meter to read the amps on the start winding connection to the run cap and then multiply times 2652, then divide by the voltage reading across the capacitor's terminals which will give you the uf of the capacitor. Compare the result to the cap's label to determine if within specs. Can't use this for Start caps as they aren't energized long enough to take the readings..
I bought a new capacitor that reads around 195 microfarads. The range on the capacitor says 161-193 microfarads. Does that mean the capacitor is bad? I believe the old capacitor reads even higher and neither capacitor will start my 1 hp shallow well pump motor. The motor will just hum and then goes quiet. I am working on the inside of the motor tomorrow checking things out to see if I can get it to run. I already cleaned the contacts on the inside but I broke a wire that was soldered and I got a new soldering iron to solder it back on. I also purchased some contact cleaner to make sure contacts are clean. My tester I believe was showing continuity through the motor contacts after sanding them lightly. If motor doesn't start I'll disconnect pump and try to start the motor without the pump to see if the motor will run.
I had no idea about the capacity setting on a multimeter, so that was especially helpful. I had been staying with my older multimeter because it seemed to do everything I needed to, and honestly, it's not auto-ranging, and for some reason, I had it in my head that the non-autoranging ones were better. I guess because it required the user to be more knowledgable. This video has me reconsidering that stance. Any thoughts/recommendations? Thanks!
Thank you Chris , Great videos , I have a problem that you may be able to answer my Frigidaire affinity atf 705b stopped working during a cycle , and i went through the the normal things that typically goes wrong like , door lock , main front control board, computer board, checked all wires for short or breakage, ( all ok ) , but when i looked at the run or start capacitor it didn't have any marking on it numbers or writing , so don't have a clue what reading it should have , so how do i check if its ok please, thank you if you can help .
Great video and thank you. I am testing a CBB60 Cap 100uF with a Fluke 87 DMM set on CAP mode and it reads O.L. I tested Both ways same reading. I swapped to OHMs, and I see 8.24 megs and it starts to climb a little - swapped it and I get -3.016 megs and it starts to go down. On the capacitance test I get nothing, no reading other than O.L. bad cap? thx
First time testing capacitors with a meter. I have two. I start with the meter showing 1 as in the video. I put the meter leads on the terminals and it shows a reading for a second then goes back to 1. Both capacitors do this. Neither shows a steady number as shown in the video. Am I correct in thinking that both are bad?
Can I use the first test or should I say ,will it work to test the capacitor on my pressure washer ? I am not that great with electrical stuff but your video seems straight forward. Thank you.
Very helpful video; my pool pump has a Genteq 25 uf 2-pole capacitor; the wires from the pump are black and were disconnected from the capacitor by my electrician when he removed the capacitor; I bought a new Genteq 25uf capacitor; I don't know which wire to connect to which connector on the capacitor; does it matter what wire goes to what connector?? Thank you. Steve
That third test using the ohm meter; you need to discharge the cap also for the small charge that is induced between application of the leads. You wont get a result that is correct otherwise!
I'm trying to get a 1 hp Baldor going that growls and has trouble getting started, once its hand started it runs fine. The capacitor had foam rubber padding wrapped around it and it deteriorated and ruined the printing on the unit, but I have another motor like it and was able to decipher the info. My question is a Packard capacitor made in China costs under 9 dollars and the Baldor made in USA is over $45. Your thoughts on if I should gamble on the cheapy one? The motor is a spare and will see use occasional on the farm. Thanks for your video, very helpful.
The Chinese caps are pretty poor quality. But you don't need a Baldor branded cap, they dont make them. BMI is US made and would be about $10 to $15 and outlast the Packard 10x
Why in the last test with the fluke do you need to put the probes on opposing sides of the terminals? Why can’t they be on the same sides of each terminal like when you used the fluke for microfarahds?
What does "OL" mean? I checked a number of capacitors and they were okay and in-range, BUT one says OL; it has two termials and I tried both ways: OL. I'm using a good Metek MK05 device that seems to work great. Thanks for the video.
Amazing video im gonna try to replace the capacitor. I have a Weg w56J 0.5hp single phase motor, but only has one capacitor, how i know if its the run capacitor or the start capacitor? Im worried because every time i connect the motor the house voltage drops from 120v to 80v and moment later backs to normal. I think this isnt normal.
the reason the voltage drops to 80 volts. First a bad connection at the main breaker to the panel. when you try to start the motor there is no back emf and a huge spike of current flows thru the motor winding, until the motor starts and the bemf reduces the current flow. there is a voltage drop is across the bad connection and thats what you see. Yeah replace the start cap. You wont have a run cap without a start cap.
Thanks Chris. Your video is really good and very informative. I watched 3 other videos and I was doing it wrong and ready for a new CAP (was getting 0L). Now I know my capacitor is good. And God bless auto-ranging meters :)
Super quick question. Replacing my air compressor run capacitor and the new one has a blue and brown wire. I have to connect them to a black and white wire from the compressor. How would i go about determining the right combo? Thanks!
My air compressor (single phase motor) starts and runs fine, but..... I have multimeter with capacitance reading and run capacitor is in the tolerance (nominally 40uF +-5% and i measured 40,2uF) . My start capacitor dont have tolerance labeled and is 100uF nominally but i measure 186uF. Is it something to be concerned about? It looks like new, no swelling, discoloration, smell etc.
@@chriscraft77022 thanks. Curious if discharge would reduce the newly capacitor to be able to hold charge effectiveness when actually replaced to washer. I don't know know why it creates a single spark, as I think that new capacitor would have unlimited charges in it anyways, like a car battery. I guess capacitor is not like a car battery but holds a charge, but why only a single charge why not more like a battery? Thank you Chris Craft.
Hey love the video . I have a question . On my kobalt 8 gal air compressor it is a 120 oil less compressor. The capacitor I was going to replace the start cap is a 250 mfd 120v the run cap is a 6mfd but does say whither it 120v or 230v I’m trying to match it up with one to buy. What should I do? Both caps are a two wire connectors male spade.
The voltage rating on a capacitor is simply the maximum voltage it can withstand before the smoke comes out. You could use a 230V capacitor in place of a 120V unit. You just don't want to use a capacitor with a voltage rating lower than what you removed. It's slightly easier to manufacture a 120V capacitor than a 230V unit (for the same mfd), so you might find that package size or cost may be different.
real world stuff. Thank you! I have one reading just below the 5% range.... 41.17 of 45 uF rated +/-5% ... I'm inclined to think that this isn't the problem.. Replace anyways?
Why isn't my meter showing any capacitance on any of the new run capacitors for my furnace? I thought I bought a bad one (7.5 x 370) from Grainger because it and the suspected bad one it was replacing were both showing 0 capacitance on my cheap meter. So I returned to Grainger with the suspected bad one I just bought from them, the suspected bad one that came off the furnace and my meter. They brought out several new capacitors and my meter never registered any capacitance on any of the capacitors. So my question is why is my meter not showing any capacitance on ANY capacitor? Thank you.
On the capasitor setting, the on I have goes up the .OL in both directions. One side is higher than the other. So I guess this cap is bad? The resistance test goes up then .OL, jist like the cap test, but higher numbers.
What is the best way to identify your capacitors? how do you tell the difference between the start cap. and the run cap. if they sit side by side in a black box fixed to the motor on my air compressor?
Start caps are usually black plastic and have a high rating 100++mf - runs are usually aluminum and low rated, like 10 to 25mf with voltage ratings 300+
I followed you instruction and tested with a Fluke 79 meter a start cap 40uf with the terminals held steady the meter went up to 39 and immediately dropped to OL , I then reversed the lead and it did the same thing. So is that an indication it's bad cap?
@@chriscraft77022 I have a five horsepower 240 volt hot tub pump motor and it keeps blowing fuses the minute I hit the auxiliary to start the the that side of the tub it started doing it shortly after I bought the hot tub and the guy told me to put a bigger fuse in it it worked a while and then this summer I started up the tub and it it would blow the fuse instantaneously . It's a 40uf 370 VAC cap in a black plastic round housing. I didn't bother doing anything until I closed down the spa this fall and tear into it to see what's causing it. I tested the motor windings and they are fine there's nothing shorted out with that and determined it's got to be the capacitor mind you I am certified in HVAC and I'm familiar with capacitors but not on motors like this.
@@DebGood if it is a single phase then it has 2 capacitors.. or does it have a DUAL..? all you can do is replace it to start with... when they pop the fuse instantly it is most like the start cap.. thats what my latest capacitor fail was doing.. any way.. let me know what you find out.,,
That's a good cap by that test if the meter is set to read resistance. but what you want is to set your meter to capacitance and get a reading near 40 that holds
Sir may I ask, if I have a motor starting capacitor for "Dough Mixer" of 80µF 10+20% 270V, and I have a reading of 85µF, shall I say that the capacitor is in excellent condition? Your info for this is highly appreciated.
I've disconnected the wires from the air conditioner capacitor. I did not disconnect the capacitor from the bracket that was holding it. So, do you have to disconnect the capacitor from its bracket to get a good capacitor test?
my problem and suspicion is this capacitor/ washer is not washing or spinning back and forth and its weak spinning back and forth and I want to be certain to change the capacitor whirlpool 6 sense 18kg can it be the mainboard or the capacitor???
Cool thanks! Am I the only one wondering why the lighting exposure freaks out only when you have the test probes on the poles of a cap? Is some kind of stray flux from the low powered test freaking out the electric eye that determines the brightness? Not complaining -- I think it's fascinating
Just a note about the voltage stored in the capacitor: it's DC. Even though you applied AC voltage, the capacitor only stores DC. This is why caps are used in AC to DC power supplies.
Depending on timing it could be anything from 0V to 120VAC RMS / .707 = 169.73VDC because that is the peak AC voltage. If it was a circuit with a full wave bridge, it would be about 340VDC for the AC peak to peak value.
As a wild off topic side note, a real telephone line rings at around 170V 20Hz pulsating DC. Nominal is 48VDC from 24 lead-acid battery cells in series which can reach 58V.
Yes, a shorted cap can trip a breaker, or a fuse. The alternative would be for a lot of current to run through it, so the fuse saves you from a worse outcome.
As an electromechanical tech for the largest wire production company in the continental U.S. there is a reason techs call that power cord a suicide cord.
I know this is a little older but im fixing up an old bench grinder, single phase, has a start capacitor, the centrifugal switch looks to be good and works, well seems to work like it should however I started up the grinder with a new capacitor with the same ratings and the grinder ran for about a minute then the capacitor blew, Im thinking i just go up to the next size uf rating which is like a 10% increase, however I dont wanna spend another 15 bucks on a capacitor just to have it blow again, Could it have just been the size/rating of the capacitor or is the centrifugal switch bad.
Most probably your centrifugal switch is not going open circuit when going up to speed. To test the switch Press back in the collar you should hear the switch click open , some machines this is not possible when opened because the switch is on a separate plate. A quick check is when you start the motor, switch on for about half a second, the motor is supposed to be up to speed this fast,switch of when spinning slower you should hear a clear click sound ad the centrifugal switch makes contact again. If you don't come right let me know and I will see if I can assist you further.
Thanks, though I hated how close your hand was to the exposed conductors when performing the 'firecracker' test! When you pulled the plug out nearly swept them with your left hand. Please don't try this at home without taking far more precautions than Chris here!
Thanks for the nice video and re-education, Another good way if you have to test live is use a switch and a piece of fuse wire but still make sure its discharged before touching afterwards
The resistance test is not pointless. 1st because it shows if it is shorted or not. 2nd it shows you if it can take a charge or not and 3rd is when you switch the leads it shows you if the cap is discharging and recharging in the opposite polarity. So it's definitely not a stupid test
Grew up in My Dads electric motor repair shop. we stripped out old motors and re used most parts back in the 1970s. one of my jobs was to charge each capacitor with 110vac and then discharge with a screwdriver just as you did there. throw out the bad ones. Also, point the terminal end away from you when energizing because they can explode and blow out at the top
man brother you are my HERO! After looking at 9 videos you are the 1st person/video that made sense
This video made the difference after watching 2 other capacitor videos. Thanks Chris
Thanks for doing this video. It had been awhile since I checked capacitors and this brought it all bad. My run capacitor is bad. Simple enough to get a new one and a lot cheaper than a new motor.
When you do the Ohms test, the results you get are due to the following. The capacitor initially takes a charge and therefore shows what is in effect a current reading. When the capacitor reaches the voltage of the internal battery in the meter, the capacitor will be 'fully charged' (as far as that test set up is concerned) then no more current will flow into it and it will show an open circuit (or OL which is not really Overload). It is worth keeping the meter (set to a high resistance range) on the capacitor to see if there is a measurable resistance. This will indicate a capacitor with a poor insulation resistance and which will therefore not hold its charge. The snag with this test is that it is done at about 1 1/2 volts which doesn't stress the capacitor at all. The mains voltage charge/discharge test will only work some of the time even with a good capacitor. If the cap is disconnected from the mains supply at just that moment when the mains voltage passes through zero (it is AC), there will be no charge remaining in the cap. Indeed the size of spark you get will vary according to the moment when the cap is disconnected from the mains. If this mains test is done with a failed capacitor (short circuit in the cap) the results will be fairly spectacular. Take care!
Bad start caps nearly always announce themselves by blowing out the vent hole. run caps die peacefully and need a good tester.
Initially I got a reading then nothing but OL which had me confused so you definitely cleared things up for me. Thanks 🙏🏽
@@RRaucinathank you for this tidbit of info that just solved my problem. The vent hole being blown out. I saw this on my capacitor but did not realize it was an indication of failure. Thanks again.
Great video.
I've watched so many just trying to figure out how to test a capacitor attached to the relay of my lg fridge compressor. Even took it to couple of stores. One said it was good the other...it was bad. So confused. Your deliverance of the test method is the best so far. Thank you and God bless you.
If you can also do a video on how to test start relays for a fridge that would be great....that's the next thing I have to figure out.
Thanks for the explanation. I have a 10hp single phase Leeson compressor motor that stopped today, and started buzzing. I'm going to test the caps first.
Very helpful, the capacitor was the problem, had another capacitor off an engine that was sitting in the garage and it tested fine, engine now runs like it should.
Thank you was trying to understand this just about to do my exam so far your the only person to show discharging
I have several meters from top end to crap and I only recently discovered that one or two of them has a capacitor test setting. I had always used the resistance test, needle up and then back to zero. Feeling a bit stupid on that! In my defense, on retesting a bunch of caps judged good by using resistance, the true cap test agreed. Seems like most caps are either dead or good with little in between - especially start caps that usually blow their top.
I have that same meter and never knew of that setting. Big thanks for that one !
Nice video. Good thing you didn’t show that part with the 120 v.a.c. cord and screwdriver! LOL. I am a retired electrician and when done safely, electricity is really cool to mess with.
have you seen the video where the guy shows you how to make a 220 outlet anywhere?
@@chriscraft77022 no. I’ll have to look it up.
I’ll send you a link later.. I’m at work.. I want to know a retired electricians opinion on it
Also, you can test each termination to the frame of the cap to be sure there is no current path between them.
Right on..now I know how to use my Fluke multimeter to read microfarads
Chris you're the man. Thanks for the best explanation on the internet 👏
Love the cajones to show this, good video for the ignorant but smart not stupid people. Personally I'm not touching the second test but itwas very informative to see it work.
My wife had her friends over for a party while I was gone and someone stole my Fluke meter, When I complained she blamed me,
I divorced her and recently picked up a mint Fluke meter at a garage sale for 20 bucks, Win Win!
Wives ughhh...
I went away for a weekend, and my wife told me she was going to have a garage sale while I was gone. Awhile later I was complaining that I couldn't find my Fluke meter. It turns out she sold it at her garage sale for 20 bucks. She blamed me, saying I never told her she couldn't sell it, or not to sell it. I divorced her
@@junkyardwizard9092 Thats crazy! my wife went to a party a little bit ago and when she got home she said she got me a gift. To my surprise it was a beautiful fluke meter. I guess marriage isn't the same for everyone
Always use a light bulb to discharge a range cap, then you can get an accurate reading and its safe. 👌
Got yourself a new sub. Your explanations are clear and straight to the point. 👍
Hell yeah I've learned capitance.... again..... This time I will remember exactly how to do it on my 87,all the way till time to check my air compressor kicking the the breaker, see ya again then Chris
The best that I've seen on YT. Nice job Chris and thank you.
Excellent. Concise and to the point. You don’t waste people’s time. Congrats!
Just a quick note Make sure when discharging the capacitor that you are using an electrically rated insulated screwdriver !! Like the one he is using ...other wise it could jump through the handle
1. Never discharge with a screw driver. Put your meter on DC put your test leads on the capacitor and it will drain it, that is the proper and safe way. 2. Put your meter on ohm's and your 9 volt battery in the meter will start to charge the capacitor if's it's good you will see the values going up rather fast depending on the charge of your battery. If it does not go up fast it's bad. I would suggest a stand lone tester the Supco MFD10 capacitor tester if you repair shit from time to time. Or a meter like the field piece SC640 which has the MFD option if your always working you can have one tool that does it all.
Makes perfect since. Thanks for sharing.
you seem to be a service tech who was taught by his daddy or uncle. I remember when i was trying to learn about motor caps and how to test them. I went to a bunch of appliance and motor parts stores and tried to ask how to test caps. no body was giving it up. they either did not know or understood the value of that information. It took me a while but I finally learned how to test them and understood the value of that information too. that knowledge helped me pay my rent and foot many many time over. And you know, if a customer knows hows and whys of a breakdown you won't get the service call. it blows my mind to think why people would devalue their knowledge. the only reason you make 80 to 200 or more per hour is because of what you know. but when you give it away it is worth nothing.
Jack I understand your thought process here, but believe me when I say this. 99 percent of people are shit scared of electric, and you could show them every trick in the book, and they still would not try it. So chill man 🙂
I like electrical work am amazed at how many ppl want nothing at all to do with it. That's good for the techs
Thanks. FYI: @2:55, that's not a "u"; it's a lower-case Greek letter "mu", which stands for micro. (Mu has tails that go down below the "u" on both sides, longer on the left.)
I've found readings on my ESR meter often give different results compared to simple capacitance testing with a multimeter, the two testing devices are complementary. Presumably that unreliability of a single test is one of the reasons HVAC techs simply replace the run/start cap when fixing or replacing motors. No test is perfect.
It's not seeking the GROUND It is seeking the SOURCE.
It is seeking a lower potential.
Ground is also right what you mean ?
Thanks to this video i found the capacitor test function on my multimeter. I was confused as it is such an expensive Fluke multimeter, that there wouldn’t be a capacitor test function on it 😂 Just didn’t recognise the symbol for it. Confirmed that my start capacitor is bad & ordered a new one already 🙂 I found a water well in my backyard of which the motor doesn’t start, the motor only hums, i hope it works after replacing the start cap.
If the cap is disconnected from everything, the current will not flow to ground. It flows from one cap terminal to the other so it doesn't really matter if you're on concrete or not.
The cap can still be very dangerous. You must discharge it before touching it with your hands or meters.
A BIG TRICK is to discharge the capacitor like the book says; leave it laying on the bench and come back a little later, maybe a day later, and it will still knock you on your ass. A big capacitor does not loose all it's energy with a single quick short circuit.
Short it every time before you handle the cap.
I was told to not short it with a screwdriver, but with a tungsten lightbulb that can act as a load and not harm the capacitor.
@blackrockcity
The light bulb thing makes sense...
Does the bulb type matter? Can it be just a 12v automotive bulb, or have to be say a 120v bulb, and if so does the bulb wattage matter at all?
Very informative video. need to get a fluke meter it's a must have to diagnose electric systems. Thanks for sharing you are clear in your safety warnings but I wonder how many will find out the hard way concerning discharging the capacitor before testing it.
You can buy a Vici VC99 meter from Ebay for about $30 that is similar to the Fluke Meter
Frank W Regarding the amount functions maybe. It’s stupid to think that a 200 euro Fluke is the same league as a 30$ unknown brand. That’s like saying a Ferrari is the same as a Lada because they both have a steering wheel pedals and a gear shifter.
@@Engineer9736 I guess if one was going to race every weekend a Ferrari would be fine but if one needed a ride home once or twice then a Yugo would do the job.
@@gfinklea You are paying for the safety provided by a good quality meter. You can get accurate enough readings and a similar amount of functions from cheaper meters, but you risk your own life on the shitty build quality and inappropriate fuses of the cheap meters.
Very nice and informative, it would be helpful also to comment on the other ends of the testing probes as to which location they should be plugged into....Thank You
I'm trying to test the caps on an air compressor. One of the caps have resistors soldered into the terminals. Would those resistors cause the uf numbers to be excessively high and out of spec? the other cap is the same model and tests within range, but again doesn't have the resistors. Thanks for the video.
Best explained video yet. Thank you
i"m surprised you didn't show the most accurate test, while the cap is in circuit and energized. Use a clamp meter to read the amps on the start winding connection to the run cap and then multiply times 2652, then divide by the voltage reading across the capacitor's terminals which will give you the uf of the capacitor. Compare the result to the cap's label to determine if within specs. Can't use this for Start caps as they aren't energized long enough to take the readings..
I bought a new capacitor that reads around 195 microfarads. The range on the capacitor says 161-193 microfarads. Does that mean the capacitor is bad? I believe the old capacitor reads even higher and neither capacitor will start my 1 hp shallow well pump motor. The motor will just hum and then goes quiet. I am working on the inside of the motor tomorrow checking things out to see if I can get it to run. I already cleaned the contacts on the inside but I broke a wire that was soldered and I got a new soldering iron to solder it back on. I also purchased some contact cleaner to make sure contacts are clean. My tester I believe was showing continuity through the motor contacts after sanding them lightly. If motor doesn't start I'll disconnect pump and try to start the motor without the pump to see if the motor will run.
I had no idea about the capacity setting on a multimeter, so that was especially helpful. I had been staying with my older multimeter because it seemed to do everything I needed to, and honestly, it's not auto-ranging, and for some reason, I had it in my head that the non-autoranging ones were better. I guess because it required the user to be more knowledgable. This video has me reconsidering that stance. Any thoughts/recommendations? Thanks!
Thank you Chris , Great videos , I have a problem that you may be able to answer my Frigidaire affinity atf 705b stopped working during a cycle , and i went through the the normal things that typically goes wrong like , door lock , main front control board, computer board, checked all wires for short or breakage, ( all ok ) , but when i looked at the run or start capacitor it didn't have any marking on it numbers or writing , so don't have a clue what reading it should have , so how do i check if its ok please, thank you if you can help .
Well done ! God bless you Chris !
Great video and thank you. I am testing a CBB60 Cap 100uF with a Fluke 87 DMM set on CAP mode and it reads O.L. I tested Both ways same reading. I swapped to OHMs, and I see 8.24 megs and it starts to climb a little - swapped it and I get -3.016 megs and it starts to go down. On the capacitance test I get nothing, no reading other than O.L. bad cap? thx
First time testing capacitors with a meter. I have two. I start with the meter showing 1 as in the video. I put the meter leads on the terminals and it shows a reading for a second then goes back to 1. Both capacitors do this. Neither shows a steady number as shown in the video. Am I correct in thinking that both are bad?
Can I use the first test or should I say ,will it work to test the capacitor on my pressure washer ? I am not that great with electrical stuff but your video seems straight forward. Thank you.
Very helpful video; my pool pump has a Genteq 25 uf 2-pole capacitor; the wires from the pump are black and were disconnected from the capacitor by my electrician when he removed the capacitor; I bought a new Genteq 25uf capacitor; I don't know which wire to connect to which connector on the capacitor; does it matter what wire goes to what connector?? Thank you. Steve
That third test using the ohm meter; you need to discharge the cap also for the small charge that is induced between application of the leads. You wont get a result that is correct otherwise!
I'm trying to get a 1 hp Baldor going that growls and has trouble getting started, once its hand started it runs fine. The capacitor had foam rubber padding wrapped around it and it deteriorated and ruined the printing on the unit, but I have another motor like it and was able to decipher the info. My question is a Packard capacitor made in China costs under 9 dollars and the Baldor made in USA is over $45. Your thoughts on if I should gamble on the cheapy one? The motor is a spare and will see use occasional on the farm. Thanks for your video, very helpful.
The Chinese caps are pretty poor quality. But you don't need a Baldor branded cap, they dont make them. BMI is US made and would be about $10 to $15 and outlast the Packard 10x
@@RRaucina, thank you sir! I got it running, bought the Packard. Will note this for next time.
Why in the last test with the fluke do you need to put the probes on opposing sides of the terminals? Why can’t they be on the same sides of each terminal like when you used the fluke for microfarahds?
What does "OL" mean?
I checked a number of capacitors and they were okay and in-range, BUT one says OL; it has two termials and I tried both ways: OL. I'm using a good Metek MK05 device that seems to work great. Thanks for the video.
On the capacitor in this video, what is the little button thing next to the terminals?
Thanks Chris. I had no idea that -|(- meant capacitance. Every video I see always shows uF on the multimeter.
Did you replace the compressor capacitor, and did that fix it (and stop the breaker from tripping)?
yes, of course.. thats why i made the video... cause the compressor failed.. it has been running since i made the video...
Thanks for useful information without the history and the theoretical operation of a capacitor. Hopefully will be repairing my AC for $11.00.
I hope that is the problem.. let me know if it fixes it...
Amazing video im gonna try to replace the capacitor. I have a Weg w56J 0.5hp single phase motor, but only has one capacitor, how i know if its the run capacitor or the start capacitor? Im worried because every time i connect the motor the house voltage drops from 120v to 80v and moment later backs to normal. I think this isnt normal.
the reason the voltage drops to 80 volts. First a bad connection at the main breaker to the panel. when you try to start the motor there is no back emf and a huge spike of current flows thru the motor winding, until the motor starts and the bemf reduces the current flow. there is a voltage drop is across the bad connection and thats what you see. Yeah replace the start cap. You wont have a run cap without a start cap.
@@johnconrad5487 So i replaced with a new one start capacitor but voltage still drops 😔
@@joseph181516 did you read what John wrote to you?
@@johnconrad5487 Start caps will have a high rating, 108 and up. Run caps are usually 10 to 25mf. I have seen some Euro motors with just a run cap.
@@johnconrad5487 The start winding may just be shorted and causing the unusual draw, you dont need a loose connection.
Thanks Chris. Your video is really good and very informative. I watched 3 other videos and I was doing it wrong and ready for a new CAP (was getting 0L). Now I know my capacitor is good. And God bless auto-ranging meters :)
Thank you Chris. I have been testing my capacitors incorrectly.
What if the meter reads OL when checking the capacitor. I have an AMES. It reads one Capacitor but not the other.
Small question, the 40 microfarad one, that was giving 35, should be a start capacitor, not a run capacitor. Am I correct here?
no
Its a good actually very good video to learn. Thank you very much, Sir. Syed
Super quick question.
Replacing my air compressor run capacitor and the new one has a blue and brown wire. I have to connect them to a black and white wire from the compressor. How would i go about determining the right combo?
Thanks!
Thanks out all the videos yours helped the most!
My air compressor (single phase motor) starts and runs fine, but..... I have multimeter with capacitance reading and run capacitor is in the tolerance (nominally 40uF +-5% and i measured 40,2uF) . My start capacitor dont have tolerance labeled and is 100uF nominally but i measure 186uF. Is it something to be concerned about? It looks like new, no swelling, discoloration, smell etc.
Practical teaching -the best , thanks Chris for those graded tests methodically verified . Perfect 👌
I have watched dozens of videos this is the best thank you 🙏🏿
Would not a power strip with an on/off switch activated for one second be better than plugging and unplugging the receptacle end of the wire?
it was to just show you.. normal people should never do that
For the second test, when you're applying live ac voltage to the capacitor terminals, what if there is an internal short in the capacitor?
Do I need to discharge a newly packaged capacitor as well if I want to test it? Thanks. Gr8 video. No words but thank you!!!
I would
@@chriscraft77022 thanks. Curious if discharge would reduce the newly capacitor to be able to hold charge effectiveness when actually replaced to washer. I don't know know why it creates a single spark, as I think that new capacitor would have unlimited charges in it anyways, like a car battery. I guess capacitor is not like a car battery but holds a charge, but why only a single charge why not more like a battery? Thank you Chris Craft.
@@educationX Batteries are designed to deliver their energy more gradually than are capacitors.
Hey love the video . I have a question . On my kobalt 8 gal air compressor it is a 120 oil less compressor. The capacitor I was going to replace the start cap is a 250 mfd 120v the run cap is a 6mfd but does say whither it 120v or 230v I’m trying to match it up with one to buy. What should I do? Both caps are a two wire connectors male spade.
The voltage rating on a capacitor is simply the maximum voltage it can withstand before the smoke comes out. You could use a 230V capacitor in place of a 120V unit. You just don't want to use a capacitor with a voltage rating lower than what you removed. It's slightly easier to manufacture a 120V capacitor than a 230V unit (for the same mfd), so you might find that package size or cost may be different.
real world stuff. Thank you! I have one reading just below the 5% range.... 41.17 of 45 uF rated +/-5% ... I'm inclined to think that this isn't the problem.. Replace anyways?
replace it
Why isn't my meter showing any capacitance on any of the new run capacitors for my furnace? I thought I bought a bad one (7.5 x 370) from Grainger because it and the suspected bad one it was replacing were both showing 0 capacitance on my cheap meter. So I returned to Grainger with the suspected bad one I just bought from them, the suspected bad one that came off the furnace and my meter. They brought out several new capacitors and my meter never registered any capacitance on any of the capacitors. So my question is why is my meter not showing any capacitance on ANY capacitor? Thank you.
On the capasitor setting, the on I have goes up the .OL in both directions. One side is higher than the other. So I guess this cap is bad? The resistance test goes up then .OL, jist like the cap test, but higher numbers.
Thanks Chris the only thing that bothers me how do i connect a 3phase motor running off a 220v it is a 2.2kw i have te caps but how do i connect.them
What is the best way to identify your capacitors? how do you tell the difference between the start cap. and the run cap. if they sit side by side in a black box fixed to the motor on my air compressor?
does the compressor instantly trip breaker or start then trip? one has a lower value I forgot
Start caps are usually black plastic and have a high rating 100++mf - runs are usually aluminum and low rated, like 10 to 25mf with voltage ratings 300+
I followed you instruction and tested with a Fluke 79 meter a start cap 40uf with the terminals held steady the meter went up to 39 and immediately dropped to OL , I then reversed the lead and it did the same thing. So is that an indication it's bad cap?
what is the machine doing? the test should hold at the reading and not fluctuate ... why are you testing cap in the first place?
@@chriscraft77022 I have a five horsepower 240 volt hot tub pump motor and it keeps blowing fuses the minute I hit the auxiliary to start the the that side of the tub it started doing it shortly after I bought the hot tub and the guy told me to put a bigger fuse in it it worked a while and then this summer I started up the tub and it it would blow the fuse instantaneously . It's a 40uf 370 VAC cap in a black plastic round housing. I didn't bother doing anything until I closed down the spa this fall and tear into it to see what's causing it. I tested the motor windings and they are fine there's nothing shorted out with that and determined it's got to be the capacitor mind you I am certified in HVAC and I'm familiar with capacitors but not on motors like this.
@@DebGood if it is a single phase then it has 2 capacitors.. or does it have a DUAL..? all you can do is replace it to start with... when they pop the fuse instantly it is most like the start cap.. thats what my latest capacitor fail was doing.. any way.. let me know what you find out.,,
That's a good cap by that test if the meter is set to read resistance. but what you want is to set your meter to capacitance and get a reading near 40 that holds
Very beneficial and informative video. Thank you!
Good video,please keep them coming!!!
What do you do if a start capacitor has a discharge resistor soldered in, how do you measure?
Sir may I ask, if I have a motor starting capacitor for "Dough Mixer" of 80µF 10+20% 270V, and I have a reading of 85µF, shall I say that the capacitor is in excellent condition? Your info for this is highly appreciated.
that would appear to be good
Is it possible that the energy in a capacitor discharges actually in the form of direct current? A/C is created by A/C generators at the power plant.
yes it does.. I am not a school teacher.. wrong channel
I've disconnected the wires from the air conditioner capacitor. I did not disconnect the capacitor from the bracket that was holding it. So, do you have to disconnect the capacitor from its bracket to get a good capacitor test?
no
I need a cbb60 capacitor , the only thing I dont understand is what does this mean -40/70/21 C Po?
my problem and suspicion is this capacitor/ washer is not washing or spinning back and forth and its weak spinning back and forth and I want to be certain to change the capacitor whirlpool 6 sense 18kg can it be the mainboard or the capacitor???
Cool thanks! Am I the only one wondering why the lighting exposure freaks out only when you have the test probes on the poles of a cap? Is some kind of stray flux from the low powered test freaking out the electric eye that determines the brightness? Not complaining -- I think it's fascinating
No, I think he just changed the contrast during editing so we can see the display on the meter better.
Thanks, I like the way you explain everything about capacitors and how to read capacitance.
The only way to test a capacitor is by ESR. The correct resistance of the inner dielectric tells you if a cap is bad or good.
Absolutly!
Just a note about the voltage stored in the capacitor: it's DC. Even though you applied AC voltage, the capacitor only stores DC. This is why caps are used in AC to DC power supplies.
Depending on timing it could be anything from 0V to 120VAC RMS / .707 = 169.73VDC because that is the peak AC voltage. If it was a circuit with a full wave bridge, it would be about 340VDC for the AC peak to peak value.
As a wild off topic side note, a real telephone line rings at around 170V 20Hz pulsating DC. Nominal is 48VDC from 24 lead-acid battery cells in series which can reach 58V.
Try discharging the capacitor first before testing on your last test and it will work every time 👍
Bro! Thanks for tutorial!! It’s helps!!
Great video man thanks, keep up the good work.
Like your assistant.
Can shorted capacitor break a protective fuse when starting a motor?
Yes, a shorted cap can trip a breaker, or a fuse. The alternative would be for a lot of current to run through it, so the fuse saves you from a worse outcome.
Thanks. You helped me a lot 👍🏻👍🏻👍🏻
As an electromechanical tech for the largest wire production company in the continental U.S. there is a reason techs call that power cord a suicide cord.
I know this is a little older but im fixing up an old bench grinder, single phase, has a start capacitor, the centrifugal switch looks to be good and works, well seems to work like it should however I started up the grinder with a new capacitor with the same ratings and the grinder ran for about a minute then the capacitor blew, Im thinking i just go up to the next size uf rating which is like a 10% increase, however I dont wanna spend another 15 bucks on a capacitor just to have it blow again, Could it have just been the size/rating of the capacitor or is the centrifugal switch bad.
Most probably your centrifugal switch is not going open circuit when going up to speed. To test the switch
Press back in the collar you should hear the switch click open , some machines this is not possible when opened because the switch is on a separate plate. A quick check is when you start the motor, switch on for about half a second, the motor is supposed to be up to speed this fast,switch of when spinning slower you should hear a clear click sound ad the centrifugal switch makes contact again. If you don't come right let me know and I will see if I can assist you further.
Thanks, though I hated how close your hand was to the exposed conductors when performing the 'firecracker' test! When you pulled the plug out nearly swept them with your left hand. Please don't try this at home without taking far more precautions than Chris here!
I don’t test them like that and I only mess with every few years
Thanks for the nice video and re-education, Another good way if you have to test live is use a switch and a piece of fuse wire but still make sure its discharged before touching afterwards
What model number is that Fluke?
Best video on testing capacitors that I've seen so far. Subscribed. Thanks!
👍👍 mystery gone on how to test
The resistance test is not pointless. 1st because it shows if it is shorted or not. 2nd it shows you if it can take a charge or not and 3rd is when you switch the leads it shows you if the cap is discharging and recharging in the opposite polarity. So it's definitely not a stupid test
Is the testing on a start capacitor any different if there is a bleed resistor installed between the terminals?
In other videos, the bleed resistor threw the readings off. They disconnected one end of the resistor before testing, then reattached.