Need suggestions: noisy Credenza electric induction motor

Share your phonograph repair & restoration techniques here
Post Reply
vichighmathguy
Victor O
Posts: 57
Joined: Wed Nov 15, 2017 12:32 am

Need suggestions: noisy Credenza electric induction motor

Post by vichighmathguy »

OK, I've had an electric Victor Credenza in my dining room for 25 years and (thanks to COVID-19) have found time to tinker with it. The induction motor was always noisier than I thought it should be so I finally took it apart to clean it (removed coils, degreased larger parts, ultrasonically cleaned smaller parts). Apart from the hum (will accept that having shimmed the coils and felt washered the coil mounts to no avail), but am very frustrated with mechanical noise coming from this motor.

Here is the sound:
https://share.icloud.com/photos/004Gxhh ... ke_St_Park

I have ultrasonically cleaned the governor and the spindle gear. In examining the gear with my binocular microscope, I saw a few small irregularities on the teeth, but were able to remove those with jeweller's files. I checked for gear "wobble" on my lathe and it only wobbled 0.004" which I think should be within factory specs. I visually examined the spindle gear while running to see if the circumference was concentric with the hole in the centre which it appeared to be. The fact that the noise is periodic with the rotation of the spindle is a strong indication to me that the gear is at fault, but I can not seem to find enough fault with it to cause the noise despite the things I have done.

Does anyone have any ideas? Does anyone know of someone exactly reproducing these gears? I can swap the motor out with another quieter one but I'm not quite ready to give up (but am getting close).

Thanks very much for any guidance you might offer.

Don Mayer

JerryVan
Victor Monarch Special
Posts: 5345
Joined: Mon Aug 24, 2009 3:08 pm
Location: Southeast MI

Re: Need suggestions: noisy Credenza electric induction moto

Post by JerryVan »

Short of sourcing a new gear, can you just try a different gear? Or, maybe a different governor shaft?

Are the weights balanced well? Any excessive play in the governor end bearings?

vichighmathguy
Victor O
Posts: 57
Joined: Wed Nov 15, 2017 12:32 am

Re: Need suggestions: noisy Credenza electric induction moto

Post by vichighmathguy »

JerryVan wrote:Short of sourcing a new gear, can you just try a different gear? Or, maybe a different governor shaft?

Are the weights balanced well? Any excessive play in the governor end bearings?
Thanks very much for getting back to me (sorry for my delay - I thought the forum would notify me of responses). Sadly, other than taking apart another motor, I don't have another gear to try. With respect to the governor shaft, I believe it to be in good shape and the weights balanced. I'm basing this on visually adjusting weight height via spring adjustment as well as observing that, for most of the rotation of the spindle shaft, the governor starts up easily and runs extremely smoothly and without vibration. The suggestion of excessive play in the governor shaft was a good one although it appears normal to me (have worked on perhaps hundreds over the years). This one is truly a mystery for me.

Again, thank you very much for your suggestions.

(Again) Does anyone make accurate reproductions of this gear?

Cheers,

Don

JerryVan
Victor Monarch Special
Posts: 5345
Joined: Mon Aug 24, 2009 3:08 pm
Location: Southeast MI

Re: Need suggestions: noisy Credenza electric induction moto

Post by JerryVan »

vichighmathguy wrote:
JerryVan wrote:Short of sourcing a new gear, can you just try a different gear? Or, maybe a different governor shaft?

Are the weights balanced well? Any excessive play in the governor end bearings?
Thanks very much for getting back to me (sorry for my delay - I thought the forum would notify me of responses). Sadly, other than taking apart another motor, I don't have another gear to try. With respect to the governor shaft, I believe it to be in good shape and the weights balanced. I'm basing this on visually adjusting weight height via spring adjustment as well as observing that, for most of the rotation of the spindle shaft, the governor starts up easily and runs extremely smoothly and without vibration. The suggestion of excessive play in the governor shaft was a good one although it appears normal to me (have worked on perhaps hundreds over the years). This one is truly a mystery for me.

Again, thank you very much for your suggestions.

(Again) Does anyone make accurate reproductions of this gear?

Cheers,

Don
Don,

I don't believe anyone makes that gear, but if I may offer another suggestion, my recollection is that the gear you're referring to is no different in an induction disc motor than it is in a wind-up motor. If my recollection is accurate, there are a LOT of those original gears available and they are not commonly "bad". Perhaps someone in the classified section can offer you one for sale.

Post Reply