Groschopp Tech Tips | How to Check for a Damaged Armature
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- Опубліковано 24 лип 2024
- Here are three quick checks you can perform with a volt/ohm meter to test a DC motor armature winding to determine if a motor armature is functioning properly.
Groschopp Tech Tips is a series of How to & How it Works videos presented by our Engineers and Technical Sales Staff to help answer your fractional horsepower motor questions.
For a written guide on how to check for a damaged armature, visit www.groschopp.com/how-to-check....
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Holy Moly Groschopp. Y'all as great as you were twenty years back. Good to see you
Thanks for the clear, concise description, nice video!
clear concise and straightforward, thank you very much, I know for sure now that my engine DC starter is good, you saved me from buying an expensive new one. keep it up
Glad we could help you out! Let us know if there is anything else we can do for you!
@@Groschopp1 great video! Helped me peice together a giant 24volt starter!
Nice! Competent engineer with good information. Thank you.
Great information, thank you for the video
Thank you so much for the tech tip I just took this job as a janitorial equipment repair and maintenance technician. I've got some idea but finding out with the ohm test will see if the company a lot of money. And it will also tell me maybe possibly how much longer the motor's got or doesn't got
Great video....simple and to the point. Thank you!
thanks a ton for the simple explanation. I wanted to know this technique real bad to check if my motorcycle starter motor armature was good or not. keep up the good job. thanks again
Very clear and professional video, thank you.
Thank you my friend. On some of them i got OL and they whent from 0.5 to 3.3 to 14. All mixed up. I also found a burned spot in the neck of the coil with little wires exposed. When i plug it in it goes bang and black smoke. Its toast lol.
Clear quick and simple tips, thanks
Thank you! A very useful tip. I might just save my Bosch saw, since rotor seems to be ok, but stator needs to be rewinded. It's burned BLACK as hell, even plastic around is melted.
Thanks for making the video. You saved me some money. I almost bought another amature for a KitchenAid mixer when the old one was fine.
Brilliant video Jim.. Well done..
Very well-done and extremely useful. Thanks!
electric current pass in commutator is good or not
Great explanation. What would you consider the variance of resistance allowable and that its ok?
A complete well explanation everyone understands easily Thanku Groschopp..
thank u sir thank u so much for this video, plz tel me about how to check field coil???
great video how do i checking winding do you have a video on that thx
HI I would like to know if there is a standard that document these testing, and yes this testing is amazing. I did the testing with a megohommeter
Hi.. Good Video.. I have a Damage Dremel, this Armature tool have 8 commutator bars.. and i note that the commutator bars are connected in two sections of four, i mean.. 4 continuous connected separated and the other 4 continuous connected.. That is Ok? All must have Connected? The Measures in Ohms all Ok. about 0.6 Ohms and i will like to Know if this is the problem.. Thanks
Thanks for the info it will be helpful.
Hi Peter, from what you described there is a possibility the armature is not centered within the motor resulting in interference with the field. To confirm this you could check the field to see if there are score marks on the inside of the field. It might be possible to center the armature when putting the motor together by taking care when tightening the bolts. If this doesn't solve the issue you may need to contact a motor repair service. Hope this helps.
Thank you. Would you pls make another video for us? How we rewind armature?
Thx Jim had a look at field and it's fine, bearings either end are fineI've got a new armature on its way so I will see what happens. Once again thx for your advice :)
should there be any reading or between shaft and lamination stack segments?
If you properly get continuity bar-to-bar going around the whole commutator in the second test, then the third test should just need to check one bar to the shaft ("ground"). It would be prudent to make sure the meter probe tips are not leaving indentations in the commutator bars (particularly where the brushes ride). Note also that the first test can usually be performed with the motor in the housing by just measuring across the brushes. This test is good for most motor configurations but there are exceptions (e.g. it won't work for a repulsion start motor, but they are rare these days).
Another good test for small motors is power the motor at a voltage just above where it starts turning (using a variable autotransformer for ac motors or a bench power supply for dc motors). Then load the motor with your fingers and check for even torque throughout a complete turn. The torque may change a little as each commutator bar crosses a brush, but should do so from bar to bar pretty evenly. The current should behave pretty consistently from bar to bar.
A final test is to run the motor at full voltage and no load. If the current is higher than expected and there are lots of sparks flying around the commutator, there is a good chance that some turns of the motor armature are shorted. Shorted turns behave like shorted turns of a transformer. That is, they may be hard to detect from dc measurements, but cause a considerable increase in ac current.
Hi Jim! Thanks sharing the video. My grinder stator only one coil is burnt. Should I change couple and another question each coil has 200 turns and I can measure the resistance and total diameter of the coil that is not damaged. Please advise whether it is possible to calculate the wire diameter to order it. (p.s: total coil length is about 30 or 32 meters 230 V 500 W 50 Hz 11000 rpm)
Great Job Thank You
The electric motor I tested passed the first two tests. I was getting high but consistent resistence on third test (bar to ground) of around 14.9 Mohms. Same reading on each commutator bar to shaft. Would this indicate a bad armature? Thanks!
Nice video thanks for posting.
Hi, Many thx for the tips on testing, I Have a bosch gof 1300 ce router, did all your tests and all seems fine, notices that parts of the stack teeth are scored and not shiney any more, fitted a new field, and brushes, motor still running at half speed and still smoking, any ideas would be much appreciated.
I subbed. Actually I was looking for this information for testing a armature. I just took apart. Pretty cruddy inside, though not surprised its a drive motor from a Tennant floor scrubber. It jumped it just sparked a little. Had to break the motor down the bolts from the face of the moter were Phillips. Slmost stripped one but like I mentioned. The armature looks bad. I'll find out soon enough. Thanks for your posting this video. Don.
Thanks for the video.
I have a motor that hums but does not turn. The shaft for my motor does not have the windings. The housing has it. The shaft has a cylindrical metal which is non-magnetic (belongs to a phase 1 bench grinder). When i tried to turn it by hand in the "on" position, it does not move. While in the "off" position, it turns just fine. I checked the capacitor and it works fine. The bearings are good too. Any ideas on what might be wrong with it?
Thank you
Awesome really helped!
Hi I have a dewalt grinder and I did the 3 test and I also had continuity in my field .I put the grinder together and it turns slowly and gets hot enough to smoke. I am not sure where I am going wrong. Question on the bars where the point touch on the 180 test . If I am off a bar or two I have the same reading what dose this mean thank you for your time.
This is a very clear instructional video. Well done. A big 👍!! This will help me with one of my projects.
I am not being critical & was considering not adding this to the comment due to you not knowing me & thinking that I am one of those trolls. But the music could be lower, mind you after years of work in loud environments ( & age 😞 ) my hearing is not what it was. Stay safe, Joe Z
Excellent thank you!
thank you
Awesome. Thankyou.
Need info about degree of slack for brushes in their holder & how to decide when brushes are too worn. I have a tool where the brushes are mounted 90 deg apart not the 180 deg you normally see, how does this influence things?
Thanks a lot.
Is it measured in ohm? How much is the multimeter set to measure the stator?
I would like to check the rotor of a burman and flex.
How long is the multimeter set
How would I test commutator bars 180° apart if my commutator has an odd number of bars? Mine has 7 bars. Thank you for a fine video.
Great Video! I performed these tests on a jukebox motor I'm having trouble with. On the 180 Bar and Bar to Bar test I recieved some readings that were a bit inconsistent. How different would they be (? %) if there is damage?
10 %
Thanks
Awesome thanks for sharing
Do you have a video on how to rebuild one? Or is it best just to buy a new one?
This video saved me $600! I was going to throw out a piece of equipment because the motor smoked and ran slow. I checked the motor per this video and discovered the problem was only the switch.
Wonderful! Glad we could help!
good video , the meter in what setting Sir
Great video. Almost ordered new brushes for my motor. After doing the test I realized the armature was faulty. you saved me $20 .Thanks
me too
Thanks! My wiper motor doesn't work, and I will try this.
even though my DC motor's winding is disconnected, motor is running fine and making pressured air.
it is a compressor motr with 18 commutator bars. one bar to bar test fail. the motor power consumtion has decresed little bit ~ 20%.
Great video information ❤️🇵🇭 thank you for sharing your knowledge ♥️👍🙂
I have a very old, very rare starter and the armature is showing to be grounded out [shorted to the armature] after getting it back from a starter rebuilding company and i was wondering since it is so rare, how would one suggest going about restoring it?
It is a high amperage, low voltage system [3.3 kw @ 24 V originally, but they ended up putting in 12v coils they said...
Also, originally designed for 4 poles, 90 degrees apart from each other, but when I got it back, I found that they had it rigged up on only 2 poles and both were the same poles, 180 degrees apart from each other.
I found this out after it only started the engine 3 times and the brushes were burned, one was broken, and as mentioned before, only half the brushes it was built for from the factory.
It is apparent that although they knew the armature was bad [perhaps before this all happened or perhaps only after, I will never know and they will never admit] and were trying to find a new one to press onto the shaft but failed, so that would indicate it is indeed pretty rare.
Should I dismantle, it clean it, re-lacquer/epoxy it and hope for the best?
I can get high dielectric, high temperature [600°F], oil resistant epoxy pretty easily, just wonder if maybe I could resolve this that way or not.
Always open to expert input.
what are the tolerance - I have an engine where all pairs are 1.5 ohm - but one pair is 1.0 ohm....
And across 180 there are further variation between 1.8 ohm to 2.6 ohm -
There are no short to ground
What if the commutator has an odd number of segments? The answer is "it doesn't matter". However it does negate the 180 degree test. It shoul be "all segments have continuity with each other".
tanks for teach
I know this is an old video, but is this test done the same on 3 phase ?
Quick easy simple thnx
hi tnx for vid coz my armature want check now i hava idea tnx and godbless
Having problem with test 2 , two segments in test 2 are giving 8.4 ohms rest of all are 0.9 what does it means plz tell
tnx
but it was clear cut explanation thank you
How to measure whether the hotstacking(welding) is done properly or not on commutator
thanks for feeding me just the tip!
But just the tip, mind you.
hi
I will be more than happy to feed your avatar more than the tip! Hahaaa!
Is the presence of fibre necessary in commutator
Hi Its me again, fitted new armature, checked the centering of the armature, motor ran at full speed for a few seconds then started to slow down again, on closer inspection i found that the bottom bearing is spinning in its housing, and there is a slight vibration on the machine, no smoke anymore, so iv'e just ordered bottom housing and bearing and top housing, wish i had have just bought a new machine now lol.
The carbon contacts are as wide as two contacts on the armature.
Does that mean that there are always two contacts are one?
There are 24 contacts.
And there are two commutator contacts with a "beep" between the contacts (second test), but both are not connected to the contacts on the other side.
I didn't pay close attention to whether it was exactly 180 °, but no contact on the opposite side was in contact with these two contacts.
Second Test:
Two contact pads beside no *beep*. Right pad (from this two) to the next contact pad *beep*. Right pad to the next pad no *beep*. Right pad to the next contact *beep*, and right pad to the next contact *beep* etc..
Two times next to each other: No contact.
The vacuum cleaner suddenly stopped working.
A Sebo Felix with Amatek Italia "E 063200099" 1200W motor.
After opening the device, the motor suddenly worked outside the housing. But not always. And with sparks.
Do individual defective commutator connections lead to electrical brush sparking?
Большое спасибо
6000 lbs badland winches. it shorted to ground. I took the neg. brushes loose no more short. Any Ideas?
God bless u but I want u do the armarture rewinding in engilish
Ive got a vacuum motor, that when turned on excessive sparks and after 3 seconds it starts to slow down and a burning smell. I took it apart and did a Bar to Bar test. Most were 01.0 except for two of them which was a 02.5. I'm guessing 02.5 is not good obviously. Whats wrong with it ? Should I trash it ?
You can replace the commutator and put new windings on that same core. Just find a local electromechanic to do it for you. Cheers
What a intelligent answer..... That must've taken some time to come up with that. Cheers to you Bljuzga My problem is solved.
sir please explain about growler test too won't growler test work out to test armature of a motor ?
Yes, a growler test will work as well. We use them here at Groschopp. However, we chose to do the test in the video by simply using a multi-meter, as most people don't have a growler.
+Groschopp USA ok thank you
Why my car radiator fan communitator and brushes get very hot please?
wait, since when was the shaft used as ground? I thought there's an insulating layer under the commutator and that power goes in and out the brushes?
I'm sitting here thinking how to test if my washer motor is good the washer won't spin so I pulled the motor out tested wires continuity it seems ok now I would want to directly energize it see if it runs I just don't have a way to use a socket out to power the terminals but I will keep thinking where to find wires that I can plug to an out let then I will know if the motor is still good and by the way it smells like shorted wires I'm thinking the motor isn't good anyone with a suggestion?
+alfred kabura If the washer sounds like the motor is running but it's not spinning it could be that the agitator is stripped. This is a common problem. They are made to where if there is a problem such as an extremely overweight load or something gets caught or bound up in the washer the agitator will strip to keep major damage from happening such as a burnt up motor or a mojor shaft breaking.
How to check BLDC motor winding ?
traduccion al español porfavor
how to find whether field winding is fine? Pls give details by measuring with multimeter
I think that you test the top and bottom separate check continuity on the in and out wire's then make sure there's no continuity between the inner shield and each wire . And the outside shield and each wire. Good luck and I hope that your motor spins smoke free.
If there is a short to ground wouldn't it show up on every segment because they are all connected and the small resistances involved would make it impossible to pinpoint, isn't that the reason they used to use a 'growler' ?
+Robert Paterson Yes, in general if one segment is shorted to the ground/shaft they will most likely all measure a short to ground. A growler is used more for determining if there are wire shorts within a coil or to determine which coil is connected to which comm bar-it can help you determine if the armature is wound correctly, or help to determine the winding of an unknown armature. Hope that helps!
I've just diagnosed an armature with leakage to ground. It's 40k ohms and exactly the same on each bar. How could it possibly be any different on another bar? The low resistance of the windings are insignificant compared to the leakage resistance so it doesn't matter which bar you test on.
If your multimeter reads no leakage when tested on one bar, you can stop testing.
Edpañol
Traducil al español
Dear Sir, I have a 1 phase electric motor that doesn't use carbon brushes. Used unused washing machines. Specifications of 230 volts AC 50 Hz 3.4 amp 100 watts 2800 rpm, SOLE brands made in Italy and 7 cables in light blue, gray, orange, brown, black, red and white orange. I have checked prisoners light blue - gray = 63 Ohm, light blue - orange = 58 Ohm, light blue - brown = 63.1 Ohm, light blue - white orange = 18.4 Ohm, gray - orange = 84.3 Ohm, gray- ash - brown = 89.4 Ohm, gray - orange white = 45.1 Ohm, orange - brown = 84.4 Ohm, orange - orange white = 41.2 Ohm, brown - orange white = 45.9 Ohm, black - red = 27.4 Ohm / alarm sound. Can you help me to determine which connection is phase and neutral.
Good sir but recently I have replaced new armature but it is heating sir why?
Ravi Kumar Bhai carbon brush change kardo or bhi bhi baat na bane to winding problem honi chahiye .. body se coper wire touch hota hoga
Is it ac or dc armature??
Is there any way to diagnose without pulling everything apart? I notice my car polisher takes a few seconds to start. I'm guessing it's the armature as it feels like it's something to do inside with the magnetic field.
Sorry if I sound silly, I'm a total noob
Self rpm disel car
Thanks for the instructions and a serious request. Please remove the darn background music. It adds no value at all.
Not a good test! A growler is the ONLY foolproof way to test.
As usual, yet another guy making a video that's totally useless to a beginner!! Meter setting? naming of parts that mean nothing to a beginner and more....
Thank you
Thank you