Clock Coil Identification Help

[gordonf]

I've been working on two Yorke clocks and need some help from the folks on this forum.  After thorough disassembly / cleaning / minor repairs, etc. I found that one of the clocks has a noisy coil.

I've read that some of you have used spray on varnish and fiberglass tape to fix buzzing coils.  I'm thinking of trying that. Before I go down that road, I'd like to find another coil from a donor clock.  I'm concerned that I may have problems getting the paper covering off the noisy coil or otherwise damaging it beyond repair.

Can anyone help with advice on other clocks that used this type of coil?  I looks like there are two "L" shaped plates.  The windings rest on the lower part of each "L", which are inserted into each side of the coil.  Each plate curves up to surround one side of the rotor. This is a "spin to start" movement.

Also, if anyone knows of someone who rewinds synchronous clock coils, that information would be helpful too.

Any advice (or humor given the frustration I've had trying to get this clock to run quietly!) would be appreciated.

Thanks,
 - Gordon.

[cable ulysses]

It would be somewhat surprising if the coil itself were noisy.  I suppose it would be possible though. Remove the frame pieces completely from the coil and apply power.  If noise, try (carefully, with kitchen gloves) squeezing the coil to identify source.  If no noise, it's in the frame or the frame interacting with the coil:  tighten all screws and maybe try plastic or wooden shims between coil and frame.  They are often shimmed at the factory.  I'd think shims would actually improve any noise problem whatever the source

It's hard to see how re-winding the coil would help unless it's burned out.

[Kid Clock]

...and sometimes we've discovered hums come from over-torqueing things.  Try a one-half back turn on various bolts and see if the hum ceases.

[gordonf]

Thanks, guys.  I have tried loosening and tightening the coil mounting nuts.  I've made sure the mounting surfaces are clean and that the fit is flush and square with the area it mounts on.  I even tried adding a second set of mounting points to reduce coil movement.  I found that the sound changes, but it doesn't go away. I haven't tried any rubber or wood pads, but I think if all was well with the coil, and they weren't there to start with, I shouldn't need them.

A second Yorke clock I rebuilt runs silently.  I may swap the coils to confirm that's the problem, but upon inspection, both have the same mountings, rotor alignment, etc.  The coil resistance is different (1.37 K ohms for the quiet clock, 1.51 K for the noisy one), but I've found varying resistance between Telechron coils, too.

Any experience using the spray on coil varnish?

[cable ulysses]

Obviously this is more an art than a science.  It is a battle you will win.