Clausing 8520 Power feed

[gajunkie]

Took apart and cleaned up the power feed that came with my 8520. Prior to disassembly, the unit worked ok but seemed to be scroll faster in one direction compared to the other, so I wanted to investigate.

Problem seems to be in the potentiometer which is huge! Maybe thats not what its called for this application, or it's something else entirely, but that's what I'm calling it lol. I'll add a short video so the experts here might be able to tell me if its no good, or fixable. Under the wiper arm you can see a small retaining clip or something, It seems like theres not much down pressure on the wiper and maybe that clip is supposed to be positioned to help with the downforce on the wiper?? I dunno, just seems like an excessive amount of sparking to be working correctly.

While motoring, it has a faint burning smell also. Took the endcap off the motor, and could see some darkness on the windings. Thinking this thing got hot at some point. If both the motor and the pot need repair or replacing, is there any hope or is this better sold for parts??

 

[mksj]

It is not a pot it is an autotransformer (Variac) or variable transformer. It should not be sparking like that, might need a new brush or replaced. They are usually like $70-90, brush around $10. Looks like a 10B model, need to match the voltage, frequency and amps (VA).

SUPERIOR - 10B - Variac. Out: 0-120V/0-132V 2.25Amp.

Transformer, variable. Variac. Input: 120V 50/60Hz. Output: 0-120V/0-132V. Amp: 2.25, max KVA: 0.36 NIB. Mount: Panel.

www.electronicsurplus.com

Variacs: 1.25 amp to 4.9 amp

www.surplussales.com

Autotransformer - Wikipedia

en.wikipedia.org

 

[gajunkie]

Thank you! I will take a look!

 

[woodchucker]

well, just viewed the video, first clean the brass with an eraser, that is not clean. It might help, there maybe enough oxidation to be interfering with the connection.

Also if that doesn't work, take a piece of silicone oxide (wet/dry paper) slip it between the brush and brass, and run the brush back and forth, just clean up the contact area a little. Clean the area after I don't know if the windings are shellac based, so use a contact cleaner which should be a good medium.

 

[gajunkie]

well, just viewed the video, first clean the brass with an eraser, that is not clean. It might help, there maybe enough oxidation to be interfering with the connection.

Also if that doesn't work, take a piece of silicone oxide (wet/dry paper) slip it between the brush and brass, and run the brush back and forth, just clean up the contact area a little. Clean the area after I don't know if the windings are shellac based, so use a contact cleaner which should be a good medium.

Got back to this project today and did what you said. Works much better now and the arcing is gone!

Now I wish I wanted to use this on my mill, but I just can't see a reason to use it for the kind of projects I do. I can see it better used for a production type scenario, but most of my projects are small one-off pieces or some kind of repair where I'd rather have another handwheel on that side. I don't yet have a DRO setup on this machine so having both cranks and dials on the X-axis is advantageous for me. Or maybe I don't know, what I don't know about power crossfeeds on the mill lol.

Prob list it on ebay soon and put the money towards more tooling.

Thanks for the help!

 

[Eyerelief]

You might want to think about using it. Power feeds aren't just for speed. For instance, if you find yourself using a facing mill, flycutter or the like, a power feed is great for producing a good finish. The consistent feed rate can be hard to achieve by hand.

 

[jwmay]

What are the odds ot would fit on a rockwell? Lol. I'd love to avoid all the machining necessary to adapt a alsgs.