I'm looking to control the speed of a single-phase, C-frame 110VAC fan motor (typically found in bathrooms) with a simple variable-frequency- drive circuit, to learn how variable frequency drives work. IIRC, these C-frame motors are less than 100W.
Any books on the topic, or online schematics, for a beginner?
By the way, I browsed eBay for variable frequency drives, and noticed that most of them are for 3-phase motors. Are single-phase VFDs uncommon? If so, why?
Thanks,
Michael
simplevariable-frequency-drivecircuit, to learn howvariablefrequencydrives work. IIRC,
Yes, almost all single phase motors under 100 W are of the shaded pole variety and not suitable for VFD. Three phase motors are normally workable for VFD, though purpose wound motors work better. I have seen many VFD with single phase input up to about 20 HP, the outputs were usually 3 phase. When the motors get really serious (200 HP+) they begin to be called "adjustable frequency motor drives" (i have seen them in draw bridges and the like).
simplevariable-frequency-drivecircuit, to learn howvariablefrequencydrives work. IIRC,
Thanks for the reply. I hadn't realized shaded pole motors are unsuitable for VFD.
For what it's worth, I found this online, for pretty cheap:
Half a horsepower minimum (just under 400W) though.
Thanks,
Michael
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