[GooberFish]

Hi, I have a 120v 4.5amp 1000rpm (1/4hp) 3 speed furnace fan motor and want to use some sort of Fan Speed Controller to lower the RPM down to about 1-4rpm without losing amperage and hp.

I've tried this with a blender motor and it took about 2-3 fan speed controllers to get it under 15rpm. So im wondering if this motor is too powerful to stop or not? its about 6inchs diameter.

also the motor I have is a 3 speed motor and along with the two power cables has a four pronged connector with labels L M H C, anyone know what those are for? or if the motor will burnout if I dont set the speed?

-Thanks, Noob


Also I just tested it and connecting the power wires to a 120v source does not make the motor turn, I tested it with a FSC and direct to the 120v power source. I tested it with a volt meter and it doesn't look like its burnt out.. any suggestions?

 

[hayewe farm]

L M H C Low, Medium, High, and Common

Some of these motors have start capacitors that are not mounted on the motor so you might need to add one.

Have you considered using pulleys and belts to reduce the speed then add a speed controller so you don't have to crank it down so far?

 

[J. V.]

Hi, I have a 120v 4.5amp 1000rpm (1/4hp) 3 speed furnace fan motor and want to use some sort of Fan Speed Controller to lower the RPM down to about 1-4rpm without losing amperage and hp.

At 4 RPM you will have almost zero torque. Since this is a single phase motor, traditional speed controllers will not work. The best advice was given above. Use mechanical options to slow it down. Like a small gear reducer. Even with a reducer or pulley addition, I doubt you are going to get this thing to run at 1-4 RPM. Trying to run a motor itself at this speed will burn up the motor as it will not be able to cool itself. :no: