I have some motor noise. It is very light, and when I put felt pads under the 4 screws (the levelling ones, the chassis stands on them on my workbench which obviously amplifies the sounds) it does not seem any louder while on the bench than when lifted with hands. But there is the noise. Not humming type, more like dry rustle.
How much, if any, is allowed?
The motor was cleaned and lubricated, without taking the bushings out. The motor when stopped rotates for another 12 seconds or so.
Also what's important is, after the power is down, the motor spins absolutely silently.
When the platter is on (this ensures the motor will be running at the same speed for a while after the power is off) it still goes silent the moment it is off.
How much, if any, is allowed?
The motor was cleaned and lubricated, without taking the bushings out. The motor when stopped rotates for another 12 seconds or so.
Also what's important is, after the power is down, the motor spins absolutely silently.
When the platter is on (this ensures the motor will be running at the same speed for a while after the power is off) it still goes silent the moment it is off.
Hmm, this is a shaded pole motor with diagonal squirrel-cage so the only thing I can think of that makes a friction type sound is that the thrust spring washer is missing, allowing the axle end to rub the housing when energized?
Powering up the motor will generally apply an axial force to the rotor (unless its perfectly centred in the lamination stack and the squirrel cage is straight), changing its position axially (motors always have some axial play to account for thermal expansion). A spring washer or washers are often present to control the amount of axial movement and prevent the axle bottoming out. A weakened spring could also account for rubbing too.
I will get to it at the earliest possibility.
Could you maybe point me to some exploded view that shows what this washer looks like and where it is located?
Could you maybe point me to some exploded view that shows what this washer looks like and where it is located?
Look like this: Wave spring washers - compression type W2402024 - 51x61x0.6 mm | 123Bearing
Nearly every electric motor uses these to stop the rotor or its bearings bashing/grinding the end stops and allowing for expansion as they heat up. Proper name is a "wave spring washer" apparently. They are something you need to be careful not to lose or crush if you do overhaul a piece of machinery, they are light and can stick in place for a bit and then drop out.
Nearly every electric motor uses these to stop the rotor or its bearings bashing/grinding the end stops and allowing for expansion as they heat up. Proper name is a "wave spring washer" apparently. They are something you need to be careful not to lose or crush if you do overhaul a piece of machinery, they are light and can stick in place for a bit and then drop out.