Hi Chad,

the application is a lathe, After reading up on all this I think I am going to go down the AC route, I have a homann digispeed on the machine now but the setup is not as good as it could be.  This is not the fault of the digispeed, its the crap motor and controller.  Its gutless at low speed so my threads go out of pitch when the motor starts to stall.  Also the thing will only run at about half speed in reverse.

When I use CSS with very light cuts (.025") on a 5" dia steel billet the motor struggles to accelerate.

This could all be down to me expecting too much from a 6" chuck lathe,  I am used to using lathes with 36Kw spindle motors. I don't stall them very often, but it has been known

Graham.

Look at the post that I made about the compact 5 lathe that I am working on... That Drive seems to be working very well!

Many of the VFD that are for 3 phase(single phase or 3 phase input power) actually output some form of a pulse width modulated wave form that runs a 3 phase AC motor quite well. They might run a universal dc motor, but the wave forms I have seen wouldn't run most of common dc series or permanent magnet type motors.  They also don't work well to power 3 phase electronics on older machines.  Most of these usually pull one phase of AC and rectify it for the electronics.
Surplus Supply out of Omaha, Nebraska usually has some dc motor controllers that use a potentiometer to vary the motor speed.

You might try Beel Industrial Controls Ltd. (www.beel.ca) They do a SMC motor controller that might suit you. I am converting/updating
a Boxford TCL 124 lathe and it is fitted with a 180 Volt Lenze PM DC motor. They have been very helpful. Not up and running yet but tests out OK.
I am using Xylotex driver, CNC4PC isolating board and Mach3 but have a long way to go yet!

Ian

Hi Ian,

do you have any part numbers for the unit you are using.

Thanks

Graham.

Graham,

Part number was SMC-00. I had to upgrade (with help from BEEL)two on-board resistors to cope with UK mains 240 volts.
Their website (www.beel.ca), from the products tab, has a picture, specifications and a pdf manual

Ian

try yaskawa V7 seri VFD. it had Frequency input