VFD to control a spindle? What do I need?

[Allistah]

I'm currently building my second mill. My new spindle is a Kress (out of Germany) that has an onboard speed control.

I'd like to hook this thing up to some kind of control so that Mach3 can control it's speed.

What would I need to make this work? I haven't opened the spindle to see what was inside of it to see if I could bypass it's internal speed control or not. If that was possible to eliminate the internal speed control, what would I need to control this AC motor with Mach3?

From what I remember, its a 600w motor.

Thank you,

-Allistah

[Pich]

Before you can make a dicision on how to vary the speed of your spindle you would need to know if the motor is single phase or 3 phase. What kind of control does it have now? What are the speed limits you are looking for.
Using a frequency drive can be expensive and you would need a three phase motor. there are products in the market that will change Pulse width (Mach3) to voltage.
PM me if you want more info if you wish

[Allistah]

Hi there..

It's has a standard 2 prong 120v AC plug on it. It has a speed control on the side and it can go up to 24k RPMs (So says the spec). Other than that, I don't know much else. I'll PM you as well.

Heres the specs on the spindle I have: http://www.ekstromcarlson.com/kresstools.htm

[Pich]

I went to the link and looked at the motor but could not see axactly what type of motor it is.
I would imagine the controller changes the speed of the motor. Do you think that it is a permanet magnet motor? If so that you can interface with Mach 3 using the PWM output but you will need a drive for it or a interface board. I have applied the same idea on my spindle, the only difference is that I made my own motor driver.
If you are electronically inclined or may know someone, you may be able to use the existing controller or you can buy off the shelf drives that could do the same job.

[Allistah]

I do pretty well with electronics so that isn't a problem. How do you mean that I could use the existing controller? You mean the one that's inside the spindle itself?

If I had to make one myself, what do I need? Do you lose any power or anything? I also don't know what you mean when you say permanet magnet motor? I've never heard that term before.

Thanks for helping me out and pointing me in the right direction, I sure do appreciate it. :-)

-Jaime

[Al_The_Man]

Its more than likely a universal motor (AC or DC) not permanent magnet, the built in controller is probabally not isolated from the incomming ac as it would be a Triac type control, so if you hooked into it you would have to isolate the command signal somehow, it would require a bit of 'reverse engineering' of the present controller to do this.
Al.

[Allistah]

So this sounds like a pain in the butt pretty much. Maybe I'll just put a tach on it somehow and hook that into Mach3 so that I'll know where I'm at. That would work for me.

[ger21]

There's no easy way to control the speed of a Universal motor froom Mach3. You could get a seperate router speed control, and connect it to a stepper so the stepper turns the dial, but that's not a real simple solution.