Re: [CAD_CAM_EDM_DRO] Kavo spindle inverter

Hi Jon,
thanks for replying. The spindle field winding really is 24 volts not 240 and
it' s 3 phase delta, it's very small at 100 watts, and were used on the early
LPKF routhers to mill/drill printed circuit boards. It looks like a 3 phase
induction motor with a squirrel cage rotor and delta stator, no feedback for
speed, temp, or position. I've not measured the inductance yet. I can't get
specs from Kavo, they keep referring me to a distributor:
http://centerline-inc.com/products/index.php
who can't pony up any specs either. Both of them want to relate to the spindle
as though it's a black box. I've tried to power it from the Kavo 4444
inverter but I think it's for 40 volt motors, and it faults out when
connected to the motor. The inverter could be faulty, I'm unable to find out
how to test it, all I can get is an operator manual for the inverter.
I think I could handle the power switching side of an inverter, and the DC
power supply, but the waveform generator stage is out of my reach at present.
That's the missing link in the inverter chain for me.
The R/C airplane crowd uses 3 phase motors to power airplanes and many small
packaged inverters are available to serve that market. I wondered if anyone
had any experiences with those applications.
regards,
Denis

On Tuesday 30 November 2004 02:30, Jon Elson wrote:
> Denis Casserly wrote:
> >Would anyone know of an inverter circuit that i could cobble together for
> > a 50000 rpm Kavo spindle model # 4050, it's specs are 24Volt, 100 watts,
> > 83 to 833 hz, field windings are delta and .5 ohms DC each and it is an
> > induction motor as opposed to permanent magnet. I have a Kavo type 4444
> > inverter but it's not a good match for this spindle if anyone is
> > interested in buying it.
>
> Oh, this is easy. Get an AC Tech model 1000 variable frequency drive
> with the
> high freq option. It can go to 240 V and 1000 Hz. (Are you sure on the
> 24 V
> bit - could it be 240 V?) You will need series inductors between the
> drive and the
> motor. The value of these inductors depends on the characteristics of the
> motor (especially if it is REALLY 24 V). I have run a Westwind air
> bearing drilling
> spindle using a standard VFD. That limits me to 400 Hz, but I am happy
> to get
> 24,000 RPM for now.
>
> Jon
>
>
>
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