Hi Alexander

Fein make high frequency power tools for industrial use from memory 300 cycle. Maybe if you spoke to one of their agents you may find a source. I have seen a rotary converter set up for driving an entire sheet metal factory, there was a special and separate bus system. to drive the tools. They are very robust.

Regards
John

If you want to use a VFD then you need to use transformers to get from 230V to 38V. Each rated at 200W.

Your motor has a "resistance" of 38^2/ 133 = 11 ohms which is not a million miles from 8 ohms of a loudspeaker. So what I am suggesting that a pair of 200W audio amplifiers driven by a variable oscillator which has the phases of its output correct could be another way to go.

Or if you are really clever you build your own VFD

Frank

I would keep hold of it and see if you can find a use to get it working because if it's anything like the Hi-speed spindles sold by Arc they are quite expensive to replace.

Michael W

i agree with Frank and John – an old audio amp driven from a simple frequency generator should give you enough power at that frequency.

possibly doesnt need to be that big – depends on what you are grinding i guess, but an old 100 w amp should be pretty cheap, you may be able to parallel the channels.

-russell

I'd guess it's 38v RMS AC Niel not DC.

If some one wanted to try an audio amp the simplest solution would be to drive the channels in anti phase and connect the motor across the outputs of the 2 channels. Trouble is though I'd guess it was driven with a pretty simple switched DC square wave drive and inductance effects might blow an audio amp up.

If it was driven with a switched square wave the arrangement may be similar to the speed controllers used on universal motors. In that case the motor might be 180v and the speed controller has a limited a range of "speeds". The mark space ration is never 50 – 50 it's always less to control the power into the motor. The back emf duration when the drive is off is used to detect that the motor is under load which would normally cause the speed to drop. That's prevented by increasing the mark to space ratio over a limited range. I understand electric model loco's use a similar arrangement and via a DC supply.

John

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I have some hard time finding the right startup frequency and acc and dec time for my Oberg wm17. I have a vdf type sunfar E300-2s0015 (b) with rated capacity 2.9Kva rated output current 7.5A and Applied motor power 1.5KW
Can anyone help me with the settings of this parameters?

Thank you for your reply Neal.
It looks like the minimum speed for wn17 is 15000rpm.Therfor i have set the lower freq to 250 Hz
upper freq to 900Hz
acc time to 10sec and dec time 10sec
Modulate mode is set to synchronization?
Basic running freq is set to 900Hz
Max output volt to 38v
Min setting freq 250Hz
Max setting freq 900Hz

But i have not test the spindle with the aboue parameters yet because im not sure if this actually would work.
I would be very grateful if you can help me to set it up right.
Thor

Thanks Neil, to me you look like an great expert
I been told that the most important parameters that I have to set is:

1.V/Hz 0.042 (38 Volt at 900 Hz)

2.Maxfrequency 900Hz

3.I-trip 6-8A

4.acc and dec time

The only problem is that I don’t know witch off the parameters who look very similar to each outer on my vfd to correspondence with the settings mentioned above.
Eks I-trip is not a parameter on my vdf, and what is the difference of basic running frequency max frequency, AO frequency,digital frequency and sett frequency?
Acc and dec time set to 10sec was just a wild ges.
Thor