Broken Electric Motor? HOW TO Test If A Motor Armature With Commutator Is Damaged
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- Опубликовано: 29 ноя 2017
- When an electric motor is broken, one suspect is the armature with commutator of the motor. In this video, we show different tests (180 degrees test, bar-to-bar test, continuity "bar to stack" test) that can be completed to determine whether or not the problem with the motor is caused by the armature with commutator being damaged or having failed. Note that those tests apply to DC motors and universal motors that use a motor armature with commutator.
In my case, the armature, coming from an old circular saw, was found to be faulty. Was it a surprise? No. Other signs of the armature having failed included:
1) Motor not reaching full speed when using the circular saw
2) Smoke coming from the armature when using the circular saw
3) Motor not spinning at all when placing the motor brushes on A specific commutator bar (the one where the resistance drop in test #2 was observed)
4) Irregular film left by the brushes on the commutator bars
Cause of the motor failure? Short in the armature windings.
But ultimately because I'm an ass!
- Short in the armature windings was because the coils got too warm
- The coils got too warm because the tool had to draw too much power
- The tool drew too much power because I pushed an old saw (with possibly degraded winding insulation) into cutting off wood that was too thick, too fast and on a super-hot summer day, so ultimately, the tool failed because I'm an ass.
► To check the motor field coil / stator, see:
• HOW TO Test If The Mot...
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Always make sure you operate in a safe and secure manner.
For this project this means, make sure not to eletrocute yourself, even if you find it fancy
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Straight to the problem, no bullshitting, watching the video solves all your problems. Thanks! ❤
Thanks for the feedback
What an excellent find! I appreciate the pacing and just the right amount of information to get you going without being overwhelming. Extra props for being so active in your comments. I'm looking forward to checking out all you have to offer. Thank you, good job and keep up the good work!
Thanks for the kind words, hope you will find something of interest in the channel
Best presentation of this kind I've seen on YT. Congrats! :)
Thanks for the positivity!
Very practical and helpful....thank you
Thanks so much for your video !
It saved my day !
Best regards,
Good to read, thanks for the feedback
Excellent video. Going step by step....again....again.
Most youtube videos skip basic steps like setting multimeter before each test and you have to go back to beginning to see what is the multimeter set to
. Same thing with measurements....taking two measurements after each other is perfect and enough to show roughly the same reading. Nice work, LabOtomy
! :-)
Thanks for the feedback Peter X, appreciated
I was out driving my 1944 GPW ford jeep. I noticed the amp meter was not working, reading zero. I decided to head home as i became worried. The amp meter needle then moved into the negative side of the guage which indicaded the battery was been drained on energy. After a while the needle moved to show a positive charge. i thought ok, all good, jeep has fixed itself. 😅👌🏻👍🏻. As i continued along home, suddenly the amp meter went totally crazy. The needle was flicking from side to side, the higher i reved the engine, the more violently the amp meter needle flicked from side to side. 🤤😓😭😭. I made it home ok. My jeep has a 12 volt system. New external voltage regulator & battery installed 3 months ago. I didn't know what to do or where to start. I found your video , thank God. Removed the generator/stripped down. Generator internals were filthy/full of dried dirt/dust as if it was dropped in mud for 6 months, then installed in the jeep. Probably dirt from world war 2, 😅🤣. Completely cleaned the internals with contact cleaner aresol, housing/armature/commutator. Surprisingly the 2 brushes had probably 60 to 70 % left.. Cleaned commutator bars where the brushes make contact with 800 fine grit paper. Commutator bars came up like new. Filed the brush surface that contacts the commutator bars with a file, so it was flat for better surface contact with the commutator bars. Done 3 tests on the armature as per your instructions. 2 ohms & 1 continuity tests. Armature passed the tests with flying colours. I assembled generator/ installed in jeep, left the fan belt off the generator. To test the generator, i connected a wire between field terminal & armature/dynamo terminals on the generator . I then ran a 2nd wire from the positive side of the battery to the wire that connected both terminals on the generator. The negative lead must be connected to the battery. The pulley spun on it's own indicating it was working properly. Connected up wires, started jeep engine. Reved the engine to approx 700 to 900 RPM, amp meter needle moved across to the positive charge on the amp meter. Tested battery charge rate was 14.2 volts at approx 700 to 900 RPM. All the problems were caused by a gut full of dirt in the genny, 😅🤣😂 Thankyou for sharing your information, really got me out of trouble. 😂🤣😅👌🏻👍🏻👏🏻👏🏻👏🏻 Cheers from 🇦🇺
Thanks for sharing. happy to read it has been helpful
Excellent tutorial I have learned something new today - always a good day!
Thanks for the feedback
Great explanation, clear and concise! Thanks!
An important lesson, Thank you.
Congratulaciones, sólo hablo español.
Espero me puedan entender; a pesar de todo pude entender algunas cosas. Eso quiere decir que es muy explícito.
De nuevo gracias
easy to follow video, great work!
Glad you liked it!
Dziękuję bardzo, skorzystałem!!!
gracias por el tiempo que le dedico a hacer el video, muy útil la información.
Great tutorial, easy to learn..... thanks.
Welcome! Thanks for the feedback
excelente mi pana...good dato
Thank you SO much for posting this video. I have an vintage sewing machine that is not starting up when I plug it in. Hopefully it's a short in the wires or wires not connected properly and not the commutator/aperture.
It's got a plug ? That's not vintage. Vintage is the Old treadle operated Singer machine my Mother used to rattle away on when we were kids. . . .
The format, the graphics, the contents and even the music is very clear and amusing, great !
Thanks for the feedback
Nice info, thanks
very useful thanks
Thank you so much for your video, helps maintenance students a lot
Happy to help
One of the Best Tutorial DIY because he was Clear, non monotone, and easy to understand,and to the point without any bull.
I would like to know: if I purchase a motor followed hooked up wiring as per direction from rear ran fine for about one 1 min then slowed down , this is to a compressor that has ben running for 16 years so power to the power switch is more than fine. Help me. Ps this is the second motor in two days from harbor. Freight Smith and Jones 3hp
Great video, nice clear instructions👍👌👍👌
Thanks
nice...grate test, tank you
Wilcom
Very clear and simple explanation. Thank you definitely helpfull.
Great to hear!
@@TheLabOtomy hello sir
As i tested same u told in video
We have 180v dc motor rpm is 1000.....rpm is flacuating around 300+or-.when rpm is 1000
1. Cleaned the comutator.
2.fixed new carbon brush
3.at starting rmp is constant after when carbon brushes are slightly corved inside starts flactuating
Thank u
احسنت فحص مضبووط..thanks
very informative video and very good edited. Thank you
Thanks
Useful video
great test bravoooo
Excellent explanation....congratulation!
Thanks Domenico
awesome track man. it's killin me tho. was a dj for close to 20 years (tribal house, breaks, dnb, later some dubstep -i dislike joining bandwagons when they're in full swing). anyways, I stopped paying attention to the video itself and am now lost in good feelings and love of times past. thank you :) ..oh yeah, I'll make sure to watch the video again to learn some electronics :) -Art (djseek/ASF, Santa Cruz, CA)
Good to hear (WARNING / WARNING / This pun was intended... \ WARNING \ WARNING)!
Good video.
Mostly when i see the Armature of an electric motor ?
Is when my Angle Grinder stops working.
IF the bushes are worn replace them.
If Not worn, and the commutator is worn.
Then in the bin it goes and off to buy a New Angle Grinder, LOL.
I appreciate your video very much. Thanks.
Thanks MrKromy67
Rất chuyên nghiệp, cảm ơn bạn
That's a quality tutorial
Thanks Nice channel
Wow great vid all the info you need
Good to hear, thanks
Nice,
I just made a video how to repair rusty angle grinder with broken with explanation because i read the comments of this video.
Thanks.
Sangat membantu , terimakasih infonya
Thx for this video!
Welcome
..my utmost thank you to you.. I have a gbh 4-32 that has been broken for a long time and I was thinking of throwing it away but after watching this video and a few other related videos on your channel, the machine is now working.. i subscribe..
Nice Angelnoheart, always good to hear about people fixing their stuff!
good video. thank you
Welcome
Wonderful lesson about Broken Electric Motor? HOW TO Test If A Motor Armature With Commutator Is Damaged
thank you! using this test procedure now on a used motor i just bought.. do you know the difference in using a growler rather than this? does the growler induce more voltage to make shorts more noticeable? it seems as though this should work about as well.
The growler is a specialized device, so will be faster helping validating the quality of an armature insulation for eventual shorts... this said, being specialized, means it is less common than a standard multi-meter in a work-space... with the multi-meter, I also like to confirm the balancing of the coils, not sure if the growler can deliver on that (leaving the last open for any growler specialist to infirm/confirm on that statement)
thanks again! I ask because I have a motor I need to repair for my race car that is a bit hard to find, one of the people I called for help said a regular multimeter couldn't do the same job even good enough for me in my garage, considering this video and the fact that the part is mine, im going to test it this way and see how that works.
A grower is the best way
Good work
Good job 😁
You can Definately rewind the wires and use it again. The main problem isn't burnt wires, but the alloy, assembly itself, if it's still in good shape. Electric motors usually have an air cooling fan to them. Sometimes a heat sink or heat resistant shroud , thicker wires can pro long their use. How they short outs, perhaps small metal debris,melted resin, from heavy use .
Thanks>>>>Subscribed!!!
Perfect 👌👍Thank you 🙏🌹
👍🌹
Dzięki za info
To perform this test properly, a four lead, low ohms meter is required at minimum, and much better to use a growler. To properly test for grounds between the windings and the Core, a megger is really required, or at very least set your meter to the Highest ohms setting, Not the lowest. The insulation test need only be performed between ONE commutator bar and the armature Core, because All commutator bars are connected together!
sounds good. Please make a video for us with more explanation!
"The insulation test need only be performed between ONE commutator bar and the armature Core, because All commutator bars are connected together!" yeah thats the right way.i think he has no idea what is happening
Very easy and convenient. Thanks
Thanks for the feedback Zaheer
excellent video
Glad you liked it!
very useful
Thank you
THANKS FOR YOUR SHARING SIR
Most welcome
Nice video good demonstration to test
Thanks Tyrone
Thx!
Great video I have a bunch of Tecumseh Snow King starters to check.
Good luck
Great video
Thanks!
If you measure no bar to stack leakage on the first bar, shouldn't that conclude the test? Any leakage from the windings to the stack would show up on all of the bars.
Thank you.
Thank you too, you are fabulous
Thanks Master
Welcome
Great Video! I have one question. In the first testing you had appx. 01.6 ohm and you said that there is resistence drop? How do you indicate that? For examle if you measure it and it jumps right away to 01.6 ohm instead of droping from 34.6 to .01.6?
I am not the author, but I am an electronics technician. The rate of drop is immaterial, as it is a function of the circuitry in the meter, and also any residual resistance at the contact points. Just wait, and use the reading when the meter settles. The term "drop" as applied to this test is about the amount of resistance in the armature winding, which will cause a voltage drop when power is applied.
its a good video, thank you
Thanks Joseph
Hola Saludos me yamo Lázaro reparo esas herramientas es bueno estos vídeos.
So when I would did the bar to bar it went down from 1.4 to 1.3. not a big difference but it still changed. Does that indicate a problem?
Спасибо за информацию
Hi great video, how much variance in resistance is acceptable?
Plot the data and see if there are odd spike values or if the chart looks homogeneous
Tank you
Nice discription below the video tq
Thanks
nice video
Great video - has got me thinking!
Hi, testing a 6-pin universal 2-pole Bosch washing machine motor (Bosch front loader). The motor had previously seized due to a failed armature bearing. Replaced both bearings on the armature. I then checked the motor for continuity through windings, thermal fuse, to the carbon brushes and through the tacho - all appeared good according to the DMM. So, reinstalled the motor in the machine and tested, but now the motor fires up and spins the drum as you would expect, but only for just a second or so before it stops (this happens for wash, rinse and spin)???
Could this be a commutator issue as per your tests above or would any failings (shorts) here cause the motor not to spin at all)?
Sounds like the start capacitor is working but the run capacitor has failed possibly
@@alloverflorida5886 Thanks my friend! I know where the start capacitor is and I checked it for obvious signs of failure early on - not sure where the run capacitor is though?
@@intestinalworm1202 many times they are both in the same case.
My vacuum cleaner turns off after about 20 seconds, and if I keep using it that time goes down, I gotta wait about a minute in between, It also happens when I hook the motor directly too power, brushes are good, would you have any ider where I could look next.? TIA.
What I like the most is the music.Like it.
All credits to Diamond Ortiz ("That Part")
merci
hola cual es la resistencia que tiene que tener como minimo gracias
Best video on this topic. And a nice disclaimer. My field is black and has almost no insulation left. The armature has one suspicious coil. All of them are 0.3 to 0.5 but one is 0.6 , could it be normal or could this even be the reason why the field overheated? I dont know nothing obout the provious use of the mashine. It's a 15yr old dewalt but the blade was pretty dull.
So, a possible scenario in your case could have been:
1) Blade is dull, which causes
2) Motor to have to work harder, which causes
3) Motor to pull more amps, which causes
4) Armature coil to heat up beyond normal, which causes
5) Damage to the internal wiring (resulting in resistance discrepancy within the machine coils, 0.3 to 0.6 is a 100% variation which is real source of concern) and degradation to the insulation material (burning through and truning black)
6) Which causes the motor perceiving a loss of power to go back to 3) for a ultimate catastrophic failure
The Cause and effect theory at its best!
@@TheLabOtomy I could not have explained that better. Got an old dremel here that's got the same variance. I just happen to have some rolls of magnet wire that's just a little thicker than what's on it now. Time to rewind the armature and field core. Why would I do this? Because I can!! And just a little payback for pissing me off and failing when I needed it most! And from what I understand this particular model is known for this failure, and I am surprised that with this being a flex shaft only model they would have used a better quality wire and cooling fan!
In any case, Thank you for this informative video👊
I have several broken motors, and I find this video instructional because at least I can tell for certain that the motor is irreparable, (something that I already well figured out, as the vacuum cleaner does not clean and the hair dryer does not move air).
The video is very well done (artistic, indeed), and I've been hoping it could give me a hint on how to fix the coils by the bottom stack, but I don't think this is feasible with my limited capacities.
Like an egg and myself, my coils and brain are fried, it seems...
Nevertheless, the little funnies help me shed off the tears of what is now just a lump of metal...
Next, LabOtomy, sir, would you kindly show us how to actually *fix* the f'in thing?
Much appreciated,
D.P.
Thanks for the input, will think about it
At least a comment as to is it worth repairing. For most it isn't but some of us like that challenge. Why not....
@@ericsnyder3689 Excellent attitude!
handy video
Una armadura no se puede probar con un multimetro sólo se prueba con el multimetro alguna fuga se debe usar un inductometro
To test continuity to ground wrap a braided copper wire around the comm then measure from braid to stack ( ground) it is much faster.
Indeed!
if any of them are shorted to ground it will show in any of them, the resistence may be lower but any value other than open is bad
good clip
Thanks
Excellent
Thanks
Terima kasih
Good job
Thanks
Great👍👍👍👍👍
useful video like
it helps me identifying drill motor issue
Nice
nice
شكرا
مرحبا بك
very good
Thanks
Good
i have learned something today,thanks i was able to enroll in this university .😁
Good to hear
Deben decir si están aisĺadas
Hay gente que no sabe lo del instrucciones todo aparece 01 que quiere decir?
Very good
Thx
These are men I wanted to work in our large mechanic/engineering/electrical and panel beating workshop. Men with brains I mean.
I wish I knew those guys
May i add, your 3rd Test should also been done on Meg Ohm scale, reading should be higher than 1 megohm. Don't touch the probe ends as you will false readings
Before you bin it though. Try scraping out the slots between commutator segments with a piece of sharp metal that fits the gap.
Thanks mark for the tip. What would you do the with the mica you extract?
Serious tune what's the name of it?. Great explanatory video ☺️ saved it there
See the video description
My multimeter indicates 0.4 ohm resistance between probes and between commutator segments, so resistance cant drop more.
How should i know if there is short between coils?
Hi.. i have a craftsmsn router keeps turning off due to sparks..i took apart and filed the commutator good on a lathe and then i flattened the brushes good and now it works a bit better but powers off at high rpm setting...sparks...anyone have any suggestions..brushes are about 1/2 in long