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Noise Coming from the Electric Motor

12/10/2016 6:19 PM

Hi,

We are using electric motors one of our products. Some of the electric motors have a disturing sound. Presence of this sound can be on brand new electric motors or on used ones that cause warranty cost. What can be the potential root causes and how can these root cause be eliminated? Photo is below.

Thanks

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#1

Re: Noise coming from the electric motor

12/10/2016 6:38 PM

Determine the cause and fix it!

Disturbing sounds hardly describe any symptoms. Does it sound like a cat with its tail caught in the door? Does it sound like a broken doohickey?

Are the motors running free?

Driving something else?

Flying around the room?

Running backwards?

What have you done to identify the "disturbing sound"?

Have you called the supplier?

What is your position with the company?

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#2

Re: Noise coming from the electric motor

12/10/2016 9:13 PM

Sounds good to me. Why did you take it apart? Particularly since it appears you don't know or know how to measure alignment tolerances.

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#3

Re: Noise coming from the electric motor

12/10/2016 9:24 PM

Find one that is not making the noise and compare the two....the one making the noise will be different than the one not making the noise.....It might take some time to measure and compare all the measurements and lubrication and electrical characteristics, but the answer is in there someplace, just keep looking until you find it....Just a guess would be an anomaly in the bearings...

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#4

Re: Noise coming from the electric motor

12/10/2016 9:45 PM

What can be the potential root causes and how can these root cause be eliminated?

Cause: Bad motors.

Solution: Buy your motors from somebody else.

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#5

Re: Noise coming from the electric motor

12/11/2016 2:04 PM

If you have to modify brand new motors to make them work quieter then something is seriously wrong, especially if the same motors sourced previously from the same supplier were quieter.

Contact the motor supplier directly and discuss with them. If you get no help, buy new motors from a better supplier.

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#6

Re: Noise Coming from the Electric Motor

12/11/2016 4:45 PM

I worked with small, high-speed electric motors a number of years ago. One problem with the motors was a lack of dynamic balance. There was an imbalance of the weight distribution in 3-dimensions which led to serious levels of noise and vibration. I was able to calculate the offset and recommended changes to a machined flywheel attached to the motor. That fixed the problem 'good enough' for our needs.

Here's a link to some info about this subject: http://www.hinesindustries.com/balancing-articles/armature-balancing-tolerances.shtml

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#7
In reply to #6

Re: Noise Coming from the Electric Motor

12/11/2016 5:57 PM

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#8

Re: Noise Coming from the Electric Motor

12/11/2016 9:43 PM

I find noise coming from the motor less disturbing than smoke coming out from it.

Root cause will some miss aligning causing mechanical grinding.

Fix is to centre properly and apply lots of grease.

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#9

Re: Noise Coming from the Electric Motor

12/11/2016 11:23 PM

Looks to be a power window motor or similar. as stated by everybody what kind of noise? I do see it has been balanced (properly??). but the marks on the core looks like this has rubbed, maybe after disassembled? Just to name a few items that can cause noise 1. Runout of shaft. 2. roundness of shaft at bearing positions 3.Bad worm gear forming 4. Bad housing or misalignment by over tightening one housing screw before the other 5. bad bearings or no grease 6. Bad thrust Plugs or no thrust plugs 7. gear housing noise can be eliminated easily by swapping out armature with a known good one. 8.commutator Roundness and roughness will cause brush noise. most of these can be measured but if you don't have the specs it may not do you much good. Is that a piece of magnet stuck on the side of armature? Broken on chipped magnets will cause a noise too.

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#10

Re: Noise Coming from the Electric Motor

12/12/2016 4:00 AM

Pulse-width modulation speed controllers are inherently noisy when connected to something that looks like a rotating audio speaker...

One solution would be to operate the motors in a total vacuum.

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#11

Re: Noise Coming from the Electric Motor

12/12/2016 4:42 AM

Post a video, with sound, of a good and a bad motor on YouTube.

Also, note as to what usage the customer was using them, VFDs for example can damage normal motors....

Also, give ALL details, motor type, voltage come to mind. Power rating speed, also.

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#12

Re: Noise Coming from the Electric Motor

12/12/2016 5:29 AM

Are you sure it's the motor, on its own making the noise, as opposed to the motor rubbing up against the enclosure.

In any case you should try running "good" and "bad" motors outside the enclosure, and, try using different methods to support the free end of the shaft to see if you can induce or remove the noise.

What is the bearing that supports the free end of the shaft inside the enclosure like?

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#13

Re: Noise Coming from the Electric Motor

12/12/2016 7:54 AM

The cause of a strange noise coming from under the bonnet of an ancient Austin 1300 Estate turned out to be the generator belt rubbing on a displaced piece of plastic cowling in the engine compartment. 20 seconds' work in reattaching the cowling, including opening and closing the hood/bonnet, was all that was needed to rectify the problem.

Does that help?

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#14

Re: Noise Coming from the Electric Motor

12/12/2016 6:08 PM

Maybe the motors' taste in music is not shared by the listener.

Maybe the motors hum because they don't know the words.

<Still having a bad day>

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#15
In reply to #14

Re: Noise Coming from the Electric Motor

12/12/2016 6:12 PM

Funny I never thought of most humming as a disturbing sound.

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#16
In reply to #14

Re: Noise Coming from the Electric Motor

12/12/2016 6:26 PM

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#18
In reply to #16

Re: Noise Coming from the Electric Motor

12/13/2016 5:14 AM

Brilliant, thanks for sharing!!

Thats all junk nowadays.......very tuneful JUNK!

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#17

Re: Noise Coming from the Electric Motor

12/13/2016 2:12 AM

From photograph I understand that it is small h.p motor attached to gear box. You have not given full details of the motor such as h.p, if A/C or D/C drive, R.P.M, type of bearings etc, I presume it is high speed motor with rotor shaft mounted on sintered bearings which are causing noise. What are observations of motor mfr?. Have you run motor without gearbox?.

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