Re: [CAD_CAM_EDM_DRO] Pole Changing Motors?

Jon, I'm pretty sure that I recall seeing, some years back that "pole
changing" motors were to be the cuting edge of motor technology. They
actually "write" the poles in a different place, all arount the stator.
This gives you a very precise speed control. Do a search of the major
motor mfgrs like Leeson, Superior, Baldor, etc. I don't know why the
technology never caught on, because it sounded like the ideal solution to
variable speed drives. I think the units ran on 120 & 230 Vdc, with
circuitry "writing" the poles to meet speed requirements.

RayHex

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> From: Jon Elson <elson@...>
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Pole Changing Motors?
> 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.
>
> 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.
>

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.
>
>
> Jon