Ubergeek63 said:
In induction motors speed is related to frequency so you will have little, if any, luck getting the speed to change using normal methods.
You might be able to get it to slow down with a pseudo sine variable frequency inverter, but it would be very noisy and hell on the bearings.
In induction motors speed
is related to frequency, but you can slow it down reducing the voltage.
The problem is that the torque is also reduced, and with a "normal" load (constant torque) it won't be able to spin at all. A "standard" motor, if not allowed to spin, will overheat and destroy itsefl
.
BUT
>>> If the load is a fan, when you reduce the speed the torque is also reduced - A fan takes a torque that is proportional to the square of the speed (and its power is proportional to the cube of its speed)
Almost every "domestic" fan (like ceiling fans) have a means to
reduce its speed, and this regulation is achieved
reducing its voltage (with a series reactance or with a dimmer).
>>> If the motor is marked as
"Impedance protected" it means that, even at cero speed (stalled) and with full voltage applied, it will not reach dangerous temperatures.
So you don't need a frecuency inverter, the best method is a dimmer.
There are some dimmers that are built to drive only lamps, they may not accept inductive loads.
Some dimmers are built to control the speed of fans and they will work OK with your motor. Think of it as just a "small ceiling fan motor"