On 1/26/15 6:42 PM, twoten wrote:
The capacitor will shift by almost 90 degrees but I need a shift of 120.
Actually, you don't need a full 120 degrees. all you need is enough to get the rotor spinning. Once it's spinning, transformer action makes the phases all align properly.
The motor only pulls 2.5 amps per leg at 230volts. So what if I build 2 precision phase shifters from op amps and then drove the motor through some beefy analog devices like igfets? Sure they would work hard throughout the cycle and I would have to heat sink them but if I got some oversized bruisers would they not accept their hard life in a stoic fashion?
That's what your VFD is. _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla