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8F on the fritz

Jarrod

Aluminum
Joined
Jul 18, 2011
Location
Toronto, ON
[video]https://www.dropbox.com/sh/f9bis12vt03jtw3/AADRABKtFbH5FXTJMydOujxsa?dl=0[/video]

Not sure if the video is working, but I'll try again if not...

Installed this thing for a job. I was very excited to have it along for the ride, but it started acting up on the first part. Had to complete the whole job manually, since there was no time to tinker.

I've since torn the whole thing apart. An electrical engineer buddy suggested I try working the connections in and out as it seemed like there's an intermittent signal. Tried that without any luck.

Anyone ever seen this sort of behavior before? FYI the gib lock screw is unlocked. There is no visible burning or discoloration on the PCB.

Oh and yes, I know there is no oil in the housing and the oil sight is missing... on the list of parts to order.

Thanks!
 
Sounds to me like your motor is the issue. It could just be that you need to remove the motor, give it a good cleaning, and make sure you got good brushes in it. With it seeming to run in one direction and not the other, I am wondering about the wiring inside of the motor as well as the switches.


However, I am not the biggest fan of things just dangling in the air and I wouldnt trust the connections because of that. I dont think thats the issue, but it definitely isnt helping anything by being that way.

A side note, you seem to have alot of slop in the directional handle as if you are missing parts in the cam area.

Jon
H&W Machine Repair
 
Hey Jon,

Happy to hear from you!

I've read just about every post about these drives, most of which you've made some recommendation or another... I can't express how grateful I am to have someone like you, though far away, seemingly right in my shop. This site is really exceptional for this reason... went though nearly all the recommended checks I could find. I agree about the dangling wires and have since removed the guts and motor to my bench without any change in behaviour.

I just fired it up again, having replaced the fuse holder and some of the spliced connections (wasn't impressed by the little red splice things) and realized the rapid only works in one direction as well. It's still pretty choppy both ways too...

I had taken apart the motor to see if it was gunked up, which it was't to my surprise (as far as I could tell). I have a spare motor kicking around, so I may wire it up on the weekend to see if there is any change.

I will let you know... I'll need to order a few parts anyway.

Thanks again!
 
So I grabbed my spare motor and sure enough it seemed to work okay (not under load) going forward and backwards.

I went back and checked the armature resistence on the spare, which was around 500 to 600 ohms and comparded that to the wonky motor, which turned out to be around 2 MILLION ohms.The field windings showed similar resistances maybe 5 or 20 ohms... can't remember exactly.

So Jon, you were correct in your assumption. That being said, what do I do with the old motor? Is repairing the armature a reasonable venture? Could it just be dirty?

I'm actually concerned that the drive will do the same thing to my spare motor. Is there a way to check all the trim pits are correctly set? I haven't seen such a thing in the Bridgeport manual.

I also grabbed the housing, which I will tear down to see if everything is as it should be.

Thanks again for your help!
 








 
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