Re: [CAD_CAM_EDM_DRO] Re: hi-freq motors[perske etc]

machines@... wrote:

> --- In CAD_CAM_EDM_DRO@y..., carlcnc@y... wrote:
> > I run Perske and a Colombo hi-freq router motors on my cnc.
> > I have often wondered WHY ther are no US manf of this type
> > motor/spindle??
> > Surely it can't be cost vs sale price. Perske is from
> >Germany,Colombo
> > from Italy.
> > Seems to me that the European makers own the market.
> >
> > Perske,Elte,Colombo are the only ones readily available.
> >
> Carl
> It could just be that. One of my customers runs the smaller Perske
> motors at 110v 200 cycles and 220v 400 cycles running at 12,000 and
> 24,000 rpm respectivley.
> The 110v /200 cycles ones are now obsolete and the 220/400 cycles
> cost 600UKP each, about $800 for a small 2" square by 6" long motor.
> We have these rewound when they go wrong and keep 2 spare motors. The
> customer is currently running about 24 of these on small high
> precision wood boring machines.
>
> Talking to the motor rewind people their main guy tells me that
> virtually any AC motor can be rewound to any frequency. There is a
> set of calculation that work out wire sizes, turns etc for each
> application.
> They are doing a 1/2horse 440 v standard 3 phase motor at the moment
> for me to try. Once it's been rewound for 200Hz, 220v 3 phase it
> should put out 2.1 Hp according to them.

What???!!!!! You are going to take a standard, 3450 RPM motor and
run it at 12000 RPM? Are you familiar with the construction of blast
shields? Have you calculated the first critical speed of that rotor?
I have a strong suspicion it is probably in the range of 7500-10000
RPM. Are you aware of what happens when rotating machinery
is operated near the critical speed? Where are you located?
(Hopefully not near me!) Is the motor shop going to try it for you?

> I'm replacing the spindle
> with a new one that had an inbuilt ER20 collet chuck in it and the
> front bearing cover is being replaced by a special cast one that
> carries two high speed angular conntact bearings to take the side
> load. This motor is going to be tried out on a router by a guy I know
> in Texas.

Just replacing the bearings isn't going to hold this motor together!

Jon