VSD’s (variable speed drives)


Thread Starter

Gerald Beaudoin

There are certainly mechanical consideration ot be dealt with but what of the motor winding and standing waves, etc. In lightly loaded applications, there does not seem to be any “immediately obvious” negative effects. I have one motor that has been running at 115hz for 10 months and it doesn’t seem to mind, although we kept a close eye on it for several weeks! Thanks for your comments
Typically, motors are designed for +/- 5% of design frequency. A principle concern in achievng higher speeds is that the magnetic structure not saturate. Hence, the importance of the Volts/Hz ratio. As you said, mechanical concerns (and there are many) aside, then your success is probably because of the operating mode. And, because this could enlighten many of the List members, please provide some additional information, if non-proprietory: 1) Are you operating the motor in a constant-torque or constant-Hp mode? 2) Ff the latter is the voltage “clamped” (fixed) above its rated frequency? 3) What are the motor characterictics? 4) The application? Phil Corso, PE Trip-A-Larm Corp.