Re: [CAD_CAM_EDM_DRO] inverter question

In a message dated 1/16/2004 4:44:50 PM Central Standard Time,
afogassa@... writes:
Question: would a 7 amps be enough to run this spindle or they want to push
a bigger inverter just becouse it's more money?<<
Probably, twice.
Does the 200hz have something to do with the high start current? making
it impossibe a 7amps invert to start it?<<
I think so. Nearly 20 years back, I built a HUGE machine with Perske
(German) 400 Hz router and rotary converter (price of a new Jag!) and that required a
"Star-Delta contactor". That is, it STARTED with a star-connection to the
400 Hz. 3-phase, which simply means the motor was "underpowered". This "gets it
up to speed gently" (no load, of course!), and then after about two seconds,
the "second contactor" clicks in the "delta configuration", and WHOMP, it gets
full-voltage, and you just BETTER have ear-plugs in place! WHEW! It was
DESIGNED that way!

200 Hz.? That was what, 12,000 RPM? That one I did was 24,000 RPM with 400
Hz. Some SERIOUS machinery, that!

Jan Rowland


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