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AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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OK I have a .5 HP electric motor ITEM 67839 on Harbor

Customer Question

OK I have a .5 HP electric motor ITEM 67839 on Harbor Freight Website. My main goal is to connect it to a Speed controller and connect it to an outlet. I need about 20 rpm.
Have already tried connecting Harbor Freights router speed controller and had no success.
I need to build or do something today which I can build with materials at hardware stores or maybe there is something I can buy that I don't know of. Please help
Motor specifics:
1/2 HP General Purpose Electric Motor
Smith + Jones
Amperage (amps)
blowers, sanders, saws, conveyor belts and benchtop tools
Frequency (Hz)
Horsepower (hp)
Maximum speed (rpm)
1800 RPM
Open drip proof housing (y/n)
Rigid base (y/n)
Service factor
Shaft rotation direction
Shipping Weight
27.15 lb.
Submitted: 1 year ago.
Category: Electrical
Expert:  Steve G. replied 1 year ago.

Hello there and welcome to Just Answer. My name is ***** ***** I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.

I need to gather some more information from you in order to help.

Do you actually have the motor? Or are you just thinking of buying it?

Customer: replied 1 year ago.
I actually have it
Expert:  Steve G. replied 1 year ago.

Good morning. Speed control of a single phase AC motor is not the easiest. DC motors or three phase AC motors are very easy and cheap to control.

With a 1/2HP single phase motor, I know of no way to do this.

I am going to opt out of this question which will allow other electrical/electronic experts to chime in.

Hold on.

Expert:  AssuredElectrical replied 1 year ago.

Welcome. My name is ***** ***** would be glad to assist.

It may not be the answer you were hoping to receive, I can understand.

But, the previous expert is spot on with the situation, there is no way to achieve a speed control on the motor you have in hand.

Even if there was a controller for that type of motor, it is a capacitor start and most likely has a centrifugal switch inside the motor.

This switch cuts out the capacitor when the motor reaches approx, 75% of its rated speed and then the motor runs on the run windings.

So, even if you had a speed controller to work on the single phase motor, you would have to run it at 75% speed just to get it switch from start to run. .

The motor is not designed for controlling the speed electrically.

Best to get a 1/2 hp 20 rpm gear motor for the application and it would run at 20 rpm output all the time normally through the gearbox.

Used these on swimming pool covers and other special applications

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