Motor & speed control
Motor & speed control
(OP)
Hi guys,
I think DC motors' speed can be cotrolled by reducing the DC rating voltage- If this is right, does that will effect the motor's torgue available ?
And what about the AC motors, can the speed also controlled by reducing the applied AC voltage , by using variable variac for example?
Does that will effect the torque rating of the AC motor?
Thanks in advance
I think DC motors' speed can be cotrolled by reducing the DC rating voltage- If this is right, does that will effect the motor's torgue available ?
And what about the AC motors, can the speed also controlled by reducing the applied AC voltage , by using variable variac for example?
Does that will effect the torque rating of the AC motor?
Thanks in advance





RE: Motor & speed control
DC motors can also be controlled by changing the field current and the speed-torque-power carachteristic depends on motor design. You can reduce spedd by rising field current, but if motor is not designed for a high DC current for example you can burn the field coil. You should ask motor manufacturer.
In the case of AC motor, it depends on motor type, but for induction and synchronous motor the only way for reduce speed is reducing the voltage frequency.
RE: Motor & speed control
The can be used in low power applications where power loss can be toleratde. Fans are an example. I have seen units up to about 5 kW running fans with a simple triac control. Look for Ziehl/Abegg. They specialise in such high slip motors.
Gunnar Englund
www.gke.org