[GreenKeys] Help with a motor

[Ralph Irish]

Tom 

>From the sound in that short clip, I would guess motor bearings. When the rotor is under 
power, there is movement other than 'rotary' and it allow some contact with the stator. When 
it is coasting down, these stresses and movements are minimized or non-existent. If that was 
in my basement, I would remove the end caps and see if the bearing races can come out, 
without a battle. If so, hope for some numbers on any'flat area'. Don't know how that 
motor manufacturer pressed bearings on, but what goes on should come off, even if you have 
to track down a bearing puller. Chances are that with a slightly tapered steel wedge, you 
might be able to start the bearing moving. With a bit of luck, you might 'worry' it off the 
shaft if no 'puller' is available. 

Sometimes checking for excessive 'endplay' can help. A few thousandths is acceptable. If it 
gets much more than that, it is likely the bearing(s). If you do this, you might as well change 
both of them. 

Remember, if a motor can seek and find its 'electrical center', it will do so. Sometimes this is 
adhieved with more than just a few thousandths of travel. A motor in this situation will run 
much quieter once it hits the 'electrical center'. This is simply where the rotor is 'centered' 
within the magnetic extremes. If it can hit this point with minimal stress on the bearings, you 
have a quiet running motor. 

This is a misunderstood factor of motor operation and maintenance. 

For now, 

Ralph - W8ROI 

Good luck. 

73, 

Ralph - W8ROI 

- - - - - - - - 

From: til128 at juno.com 
To: greenkeys at mailman.qth.net 
Sent: Wednesday, April 1, 2020 1:23:58 PM 
Subject: [GreenKeys] Help with a motor 

Hi gang: 

I am having some difficulty with a Miniature motor (161984). I am pretty sure it is electrical, but what do I know. :-) 

When turned on and running it makes a loud noise and a lot of vibration. 

When turned off, the noise stops and it silently coasts to a stop. 

If it IS electrical the only problem I see is either the cap or the relay. 

Would anyone have an answer to this? 

I am going try to attach a short video to this message - hope it works. 

Thanks in advance for any help. 

Tom 


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