2014-07-14 16:00:10 UTC
under load) without use of VFD**. It was done on this small printing press
with a 3 HP, 3-phase motor but the customer has no multiphase power so I¹m
changing to a 220 ³single phase² 5 HP motor.
Is there any inherent issue with starting an asynchronous motor under load? A
3ph motor does this with ease, but can the same be said of an async motor?
Should I be looking at a particular design of async motor?
Also, reversing an asynch motoris this a straightforward thing to do? I'm
thinking about bringing the directional wiring inside the motor's terminal
box out to separate contactors. I'm also thinking about cross-connecting aux
contacts in the contactors to eliminate possibility of actuating both
simultaneously and some kind of timer relay to provide delay between forward
and reverse actuation.
Any observations or experience you¹d like to share would be greatly
** The customer has said ³absolutely no VFD². Apparently his business
neighbor has had nothing but troubles with VFDs (blowing the supply fuses;
smoking at least one VFD) and he is terrified of them. It¹s an emotional
issue, not a logical one so no amount of discussion can change his mind.