DC motor problems

[DPittman]

I have a DC brushed variable speed Motor on Craftex small lathe (OEM)
It just up and quit in the forward direction, reverse still seems fine. No grinding, sparking, or other abnormalities other than it just doesn't go forward. It doesn't buzz and it turns freely. I have replaced brushes in this motor before, although they showed very little wear they seemed to be faulty at the time.
I'm looking for suggestions where the problem might lie. Is it likely motor problems or more likely wiring before motor?
Damn just when I needed it the most! (well "need" might be a bit of an exaggeration).

 

[kylemp]

DC motors are pretty straightforward. If it goes in one direction, it's not the motor. It'll be the controller.
If you really want to confirm, reverse the leads.. It'll spin backwards.

 

[Dusty]

Hello, what model number is your Craftex lathe so I can have a peek at the electrical schematic(s).

For some reason I have a gut feeling it might be your forward/reverse switch even though the motor runs fine in reverse.

Bill

 

[DPittman]

Hello, what model number is your Craftex lathe so I can have a peek at the electrical schematic(s).

For some reason I have a gut feeling it might be your forward/reverse switch even though the motor runs fine in reverse.

Bill

CX700 is my model. I ended up testing wires that feed the motor and it appears the switch is fine.
I think it is a flaky motor somehow. I've ordered a new one from Busy Bee for $300! Ouch.

 

[kylemp]

CX700 is my model. I ended up testing wires that feed the motor and it appears the switch is fine.
I think it is a flaky motor somehow. I've ordered a new one from Busy Bee for $300! Ouch.

Did you try reversing the leads? If it's not brushes and it goes in one direction it really shouldn't be the motor.

 

[DPittman]

Did you try reversing the leads? If it's not brushes and it goes in one direction it really shouldn't be the motor.

No I didn't think of that! I'll give that a try. Thanks

 

[DPittman]

I reversed the leads as suggested and low and behold the motor will run forward when the direction is in the reverse position and will not run when the switch is in forward position. Doesn't that mean my switch is bad? I thought I had power to the motor when testing the switch both ways?

 

[kylemp]

It's DC, all it has to do to reverse is change polarity. You've probably got a bad switch if that's the next component in line.

 

[DPittman]

A bit embarrassed but more happy! It was indeed the switch/wiring!!! I replaced the switch and it did not work either at first but then wiggled a wire and boom off she went! I've had troubles with that darn switch in the past too and have replaced it. I think maybe all problems lie within the switch and/or loose wiring. Im going for a test run.... Thanks much for your help fellows!

 

[TheLocalDrunk]

Where you able to cancel your order on the replacement motor?

 

[DPittman]

Where you able to cancel your order on the replacement motor?

You know I lay awake last night debating whether I should go ahead and get the motor to have on hand anyhow and finally came to the decision to get it. I am afraid of the motor going on the lathe sometime down the road and not being able to get a replacement. I have several other electronic parts for the lathe on hand as it is and hope to run the lathe for a long time yet. I know the motor could be changed to something else If needed but I prefer to have a quick swap in for original equipment. I'm feeling a bit I'll about spending the cash for it but I"'ll get over it eventually.

 

[Tom O]

I have a spare one for my BB milling machine also after toasting one.