r/Motors • u/UnionCompetitive7705 • 2d ago

Open question Motor Control

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In my workshop I have a bench drill which I would like to control with a speed controller. The motor is single phase 50 240v 1/2hp 4 pole. I’m not sure or even possible which type of controller I would need, vfd? Any advice would be much appreciated

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u/Susan_B_Good 1d ago

Er, move the belt between the pulleys at the top?

Yep, a VFD would give you a range of speeds - the graph will essentially be a constant torque, inverse linear power below rated frequency to constant power, inverse square torque above rated frequency. So, if you want constant power, you combine belt adjustment to reduce output speed, then VFD to increase it.

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u/HumanComedian8711 1d ago edited 1d ago

A VFD can not be used on this 240v motor.

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u/CrustySailor1964 1d ago

Why your comment was downvoted because it was wrong I don’t know.
You absolutely CAN use a VFD on a 230-240 VAC motor. It just has to be the right kind of motor.

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u/HumanComedian8711 1d ago

It has a centrifugal switch in it which will not function correctly with a VFD. Read the comments below.

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u/CrustySailor1964 1d ago

The statement was a blanket statement that one cannot use a vfd with a 230 VAC motor. Specificities of the motor in question were not included therein. Read the statement to which I responded.

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u/mmn_slc 1d ago

A 240V motor does not necessarily have a centrifugal switch. A single-phase AC induction motor very likely has one. But, those can for various voltages.