Hi all
Are there any VFDs that provide a near-pure sine wave output that could be used as a source for other electrical equipment? Alternatively, provided the output of a 3ph variable frequency drive is maintained at 50-60Hz is it permissible to connect a transformer to one of the output phases to provide a 'smoothed' secondary output voltage?
Regards Rob Hammond
VFD's as far as I know are basically pulsed DC to look like a sine wave for the motor. Most today are PWM, pulse width modulation. Some companies call it another name.
If the drive is at a set speed, i.e. 60 hz then there should not be much more variance in the voltages than the utility feed.
Seems to me your trying to make something more complicated than it needs to be. Remember if your using the output to two sources, i.e. motor and then your transformer. The VFD will have to be sized for the job. I have seen one 40 hp drive running 2 10 hp motors. I doubt that you will be able to connect a single phased transformer with out frying the drive sooner than usual.
Just my opinion.
Connecting a single phase transformer will show the drive a load imbalance and it will most likely fault out. Those drives assume a motor load that should be balanced within a certain %.
You have to look at Frequency inverter with all pole sine filter integrated. Much expensive, large and heavy but sine wave output. Regards. Ale "Rob Hammond" ha scritto nel messaggio news:AmfAjABvyiU$ snipped-for-privacy@vici.demon.co.uk...
Quite a long time ago, (ie 15+ years), Toshiba had an industrial VFD in the
230 Volt 3 Phase flavor that would accept a single phase load. If I remember, it was below 10 Hp.I have one of the 3 Hp size driving my air compressor (although I'm doing it on 3 Phase since the motor was free. Come to think of it, so was the drive)
Likely, that one has been superceded by 5 or 6 different versions.
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