Re: [CAD_CAM_EDM_DRO] What kind of motor should I use?

JanRwl@... wrote:

> In a message dated 03-Feb-02 12:27:51 Central Standard Time,
> prototype@... writes:
>
> > The only problem, other than noise, that I'm aware of is that the price on
> > the #7518 just went up to $330 usd at discount. I paid $275.
>
> You call this a "problem"??? Think about Perske 400 Hz. 3-phase
> router-motors! The motor/collet alone is around $1000, and it is USELESS
> without the motor-generator power-converter which gives you 400 Hz. 3-phase
> power for the thing, and that will cost you another $3000 or so, and take up
> about as much room as three 5 hp "tool motors" all in a row!

Actually, most newer VFDs will do up to 400 Hz, and the voltage/Hz curve
is programmable. You can get Mitsubishi VFDs in the 1 - 3 Hp size for
about $250 on eBay.

>
> One would THINK they would design these totally-enclosed external-fan-cooled
> 24,000 RPM motors to be less noisy than the "universal" type motor which is
> noisy for you. BUT! "That's someone else's job!" is the response, and you
> get a fan in a SQUARE cast-iron duct-cover at the top of this motor, with a
> fan-disk/impeller thing inside that, resulting in a near-SIREN of a
> noise-maker! Makes the noise from the kind of motor YOU have seem like an
> infant crying in another room, door closed!

That's why Precise/Rockwell spindles use an external cooling blower.
Some other spindles, ie. Westwind, use water cooling.

Jon