What am I seeing inside this servo motor? Removable encoder shaft?

Jun 06, 2010 5 Replies

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I looked inside one of the servo motors (Y axis). Inside, I was surprised to see a circlip (retaining ring) and a setscrew. It is as if the encoder shaft was inserted into the actual motor shaft and held by a setscrew. Could that be true? If it is so, I could make any encoder shaft as long as it could fit inside the main shaft?


The USDigital encoders I have used are really finicky about centering. Also, I had some intermittent problems with their encoders last year and their idea of customer service was to charge me for another encoder and offer to refund my money if I sent an encoder back that they determined to be bad. The next motion control project I do will use Avago (ex HP) or the CUI encoders that you can get through Digikey.

BobH

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I had a similar assembly on my Harding and I made special encoder shafts. Could you make a plate that mounts right on the end of the motor case to put the encoder on? then use the cover over the encoder

Karl

The encoders I told you about look like a tight fit. Sketch it up before your order. USdigital does make smaller encoders that use a 1" wheel, or you could try the digikey ones Jon Elson likes.

Karl

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Karl, so, are you saying that this encoder shaft is indeed removable?

I just want to be sure of what you are saying.

If so, it would be trivial for me to make a shaft of the dimensions that I want and to use the most suitable encoder without being limited by the 10mm shaft diameter.

Yes, I am considering buying 4x4x1/4" aluminum squares, drilling and tapping them as appropriate and installing encoders on those. I can do it with acceptable accuracy. I want liquid resistant covers, however.

Obviously there are many possibilities and here's another one: to get encoders that have 10 pin connectors like the current Heidenhain encoders. Mount them on a plate and cover up with the existing liquid tight cover and reuse the existing cable. Would that makes sense?

i

There is a 120 minimum order for them on Digikey. US Digital has smaller encoders that I will look at, such as E5.

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