Electrical issue with my mini lathe

[markba633csi]

I've looked into those and although they are used in many small lathes, there is no documentation available or schematic.
For about the same money, if one wanted to stay with a dc system, a good used KB control might be a better choice
They are hard to kill

 

[Dirtmover]

I've looked into those and although they are used in many small lathes, there is no documentation available or schematic.
For about the same money, if one wanted to stay with a dc system, a good used KB control might be a better choice
They are hard to kill

I agree, these are way to expensive for what they are. No instructions/manual, part numbers scrubbed off ICs and no safety certifications. What could possibly go wrong!

 

[Firstram]

I agree, these are way to expensive for what they are. No instructions/manual, part numbers scrubbed off ICs and no safety certifications. What could possibly go wrong!

About 10 years ago, I bought 4 used KB boards on Ebay for $90. They're not so cheap anymore, I wish I had gotten more!

 

[Houthans]

Well, I've opted for a new servo from a sewing machine inspired by some of the threads on the German forum. I'm still working on adapting the mounting plate so that the new motor will fit, but it looks like this may just work. Hopefully, I'll get it up and running this weekend. Thanks again for all the help and Ill hopefully be able to share some pictures of a successful conversion soon.

 

[Houthans]

Well, I'm up and running again with the help of a sewing machine servomotor (750 w) and a separate tachometer. I found the conversion relatively straightforward as I had to adapt the holes in the mounting plate and had to widen the hole in the pully (from 10 to 15 mm). Thankfully, one of the video's had a great trick with an electric drill to drive the shaft so I was able to even use the lathe to widen the hole. The keyway was made with a handfile. I may want to revisit the switch (I'm now using the footpedal switch now), but for now I have a functional lathe again! I'll share some pictures later today.

 

[hman]

How did you adapt the speed control that came with the sewing machine motor? I've bought one of them not too long ago, and couldn't yet figure out a good way to set and hold the speed.

 

[Monostre]

@Houthans: I'm glad you've found a good solution! How much did you pay for the 750W motor?

@hman: In this topic a user has shown how to modify the control. You can find a solution with a simple potentiometer in the first post. He went somewhat beyond and build a new PCB for his modification. Deepl or Google should do a good enough translation (hopefully).

 

[hman]

@Houthans: I'm glad you've found a good solution! How much did you pay for the 750W motor?

@hman: In this topic a user has shown how to modify the control. You can find a solution with a simple potentiometer in the first post. He went somewhat beyond and build a new PCB for his modification. Deepl or Google should do a good enough translation (hopefully).

Do you have any kind of link to the "simple potentiometer" article? It sounds like just what I'm looking for. Thanks!

 

[Huub Buis]

I'm afraid I will need to disassemble the motor. I've just tried to remove one of the brushes and I was able to remove the spring only. The brush itself (or what's left of it) is stuck inside the motor. This probably also explains why the shaft is completely stuck.

That you can remove the spring but not the brush, is common if the brush is a bit sticky. Disassembling the motor is a good way to find the problem and clean the inside of the motor. Measure the brushes and make a note if you need to replace them (in future). There are web shops that are specialized in brushes.

Replacing the motor and/or controller can be more expensive than replacing the motor by a 600W AC servo motor and driver.

 

[Firstram]

Replacing the motor and/or controller can be more expensive than replacing the motor by a 600W AC servo motor and driver.

And not worth the money, upgrading these lathes always works out for the best!