Re: [CAD_CAM_EDM_DRO] Pole Changing Motors?

audiomaker2000 wrote:

> Hey all,
>
> I am considering purchasing a Deckel mill on which the controller is
> toast (actually almost new, but still toast somehow).
> The main spindle motor is listed as a 6hp "Pole Changing motor with
> brake" in the brochure, which is all the information I have on it.

This sounds like a bad translation, but makes electrical sense. What WE
call such a thing is a two-speed motor. These are quite common on
machines, like most Bridgeports with the 2J head (standard mill with
variable speed belt drive) are equipped this way.

> Since I'm utterly stupid when it comes to motors and motor theory, I
> am wondering what such a motor might be driven by? AC, DC, 1 or 3
> phase, or perhaps step/direction?

It will be standard 3 phase. If there was an electronic variable speed
drive
in the control, this may still be usable. Otherwise, a 10 Hp VFD unit might

be picked up on eBay, and could run this machine from single phase
power, if that is all you have.

> My concern is being able to bypass the original electronics of the
> machine and still gain control of this motor.
> Unfortunately I don't have access to the machine before I buy it and
> with all this stepper/servo stuff in my head, "pole changing with
> brake" sounded familiar. Could this be a 6HP stepper, or can you
> brake (hold) an AC or DC motor electrically?

It probably has a mechanical brake for tool changes, etc. No telling
whether
it is electrical or air operated until you see the machine. Most VFD's can
brake 3-phase motors to nearly zero RPM, saving wear on the friction
brake.

> What is the "usual" current or signal type for a braking, pole
> changing motor of this HP?

The VFD may take 4-20 mA or 0 to +10 V DC. if a late model control, it
may be CAN bus or some other industrial network protocol.
The brake and motor speed change would likely be controlled through
relays, and maybe a solenoid valve for air operated brakes.

Jon