Synchronous motor rattle

[N_Cook]

Basic plastic ones ,as in day/week mains switch timer
Anyone know the secret, other than going "electronic" ? I can see its not
the anti-counter-rotation kicker moving about. Changing orientation makes no
difference to the noise level or pattern.

 

[N_Cook]

Basic plastic ones ,as in day/week mains switch timer
Anyone know the secret, other than going "electronic" ? I can see its not
the anti-counter-rotation kicker moving about. Changing orientation makes no
difference to the noise level or pattern.

onhttp://home.graffiti.net/diverse:graffiti.net/

Add some medium-weight oil and see if that helps, or earplugs, if that
is what you call them on the east side of the big ppond.

****8

There was oil in there and I added some more, noise pattern has changed ,
and reduced level of noise, so much better than it was.
Seems to be shaded pole motor type , with small magnetised disk on a spindle
but the 2 poles from the coil are not coplanar and the functioning seems to
require axial movement of the disk, something to do with this non-planarity
? so not possible to take up axial wear, assuming basically a wear problem.
Probably circumferential wear in the end bearing surfaces allowing a complex
oscillatory movement to happen.

 

[N_Cook]

On Jun 3, 9:08 am, "N_Cook" <[email protected]> wrote:> Basic plastic ones

,as in day/week mains switch timer

makes

onhttp://home.graffiti.net/diverse:graffiti.net/

Add some medium-weight oil and see if that helps, or earplugs, if that
is what you call them on the east side of the big ppond.

****8

There was oil in there and I added some more, noise pattern has changed ,
and reduced level of noise, so much better than it was.
Seems to be shaded pole motor type , with small magnetised disk on a spindle
but the 2 poles from the coil are not coplanar and the functioning seems to
require axial movement of the disk, something to do with this non-planarity
? so not possible to take up axial wear, assuming basically a wear problem.
Probably circumferential wear in the end bearing surfaces allowing a complex
oscillatory movement to happen.

onhttp://home.graffiti.net/diverse:graffiti.net/

I have several similar timers and they all make some basic noise, even
when brand new. I put them on a soft surface and that helps quiet the
noise transmission down.

*****

I did not think , when it was open - add some foam/light rubber, between the
motor and supports. Powering the motor outside the housing, holding in my
fingers, it made no observable noise but you could feel vibration, but lay
it on a surface of some sort and the noise was obvious. I doubt the
vibration conducted through the drive pinion would be much.