Originally Posted by
Frank Pratt
Starving a dust collector does not harm the motor in any way. In fact, it will run cooler.
Frank's correct. Just to add the reasons why:
The fan motor is loaded by moving the air. Air has mass and it takes power to move it. When the motor is not moving air it requires less power.
Most of the motors driving dust collection devices are induction motors. The speed of an induction motor varies with the load. The heavier the load on the motor, the greater the slip between the rotor and the rotating magnetic field, which means the motor is rotating slower. When you block up the intake on a dust collector you'll notice that the fan runs faster, which indicates that the slip decreases, which, in turn, indicates that the motor is not as heavily loaded - and therefore takes less power.
Now, looking at cooling the motor. The air used to cool the motor is not coming from the air moved by the dust collection fan. There's a separate fan that blows air over or through the motor to cool it.
So when you block up the intake to the dust collection, the motor speeds up because it it less loaded - which means it it using less power and generating less heat - and the cooling fan for the motor is now moving faster, blowing more cooling air over (or through) the motor.
So blocking up the intake to a dust collection device will not burn up the motor.
Mike
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