[DSpeck]

I have a Cortini H105 lathe, from 1986. Mine was from a highschool in Toronto, but some time before I got it, it was retrofitted to PC control by a company called Torcam. They have since gone out of business (or were taken over, not sure). The retrofit used the same idea as we currently do, which is the standard parallel port-breakout board-stepper drivers bit. I replaced the old BB with a C10, and the lathe works OK with Mach3. I will soon get the inductive limit sensors going (if they still are OK), and thus will be able to use the turret as well as the axes.

Mine still has the original DC motor controller (manual says it's a piloted diode bridge speed control), which is 110V powered. I want to replace the motor controller with something more modern, as the speed regulation is not so great, and hasn't much damping, nor braking. I have just bought a C6 board to emulate the speed-setting pot, so once that arrives, I can have control of the spindle speed, even with the old drive.

Does anyone have recommendations for a (not too expensive) DC motor speed controller for a wound rotor DC motor (1HP, 110V line powered)? I'd like it to be able to take the output from the C6 board, and control the speed from Mach3. The original install has two encoder disks, one for index (single slot) and one with 100 positions. This second one has 2 optical pickups, situated so that when one is covered, the other is open, giving direction and speed feedback (I think). The control only allows standard forward turning, no option for reverse.

I've included a picture of the control, in case it helps.

Attachment 186358

[Al_The_Man]

You need to look at the KB line of DC drives, the 4 quadrant type will give you dynamic braking and reversal.
DC Drives Chassis and DC Chassis Drive
Al.

[DSpeck]

Thanks, Al.

I've looked at them, and either the KBMG-212D or KBRG-212D look like the right things. Can you tell which one would be the better choice for a lathe motor controller? I can't tell. The KBMG is a bit cheaper, it looks like, but I don't really know the difference in application.

When I install it, I'll have to make sure the braking isn't too harsh, since the chuck is screwed on, not camlock mounted. Don't want a faceful of fast-moving chuck...

[DSpeck]

I just had a small, niggling concern. The motor couldn't be an AC wound-rotor motor, could it? Have a look at the manual I posted here http://www.cnczone.com/forums/mini_l...ml#post1264268 on page 5 and 6 for the information I have on it. There is a schematic of the power wiring on pg 81. If it's AC, what about the control, then?

[Al_The_Man]

The parts list shows a dc brushed motor, a AC wound rotor motor would be very rare in this application, especially induction type.
It also shown a wound field.
Either controller should give you the control you want.
Al.

[DSpeck]

Thanks, Al, I appreciate the help!

Doug.