How can I wire up an old furnace fan

kwinch · Sep 29, 2021

I've got an old furnace fan I kept the last time mine was replaced. I'd like to use it for various purposes. It has a red, black, yellow and orange wire. Also a purple going to/from I'm guessing a capacitor on the side and a green ground wire. Can I wire it up to be used on 110v ? I have 220v available if required. Also how would I control the speed? I'm guessing it had various levels.

[ElectriciansForums.net] How can I wire up an old furnace fan

freddo · Sep 29, 2021

There are some labels on the motor body, do these provide any information?

kwinch · Sep 29, 2021

I believe you're onto something. Here's the label.

So would that mean I would wire a 110v white wire to the orange common and hot wire to whichever of the other 3 based on the speed I want?

freddo · Sep 29, 2021

Yes, don't forget that the unused speed wires will need to be safely insulated if they are not used as there will likely be voltage on them. If the motor has had a lot of use it would also be worthwhile replacing the capacitor.

Megawatt · Sep 30, 2021

kwinch said:
I've got an old furnace fan I kept the last time mine was replaced. I'd like to use it for various purposes. It has a red, black, yellow and orange wire. Also a purple going to/from I'm guessing a capacitor on the side and a green ground wire. Can I wire it up to be used on 110v ? I have 220v available if required. Also how would I control the speed? I'm guessing it had various levels.

View attachment 90574

A couple of the wires determine what RPM’s you want it to run. The problem is that we don’t have a diagram to tell us what wire does what.

DPG · Sep 30, 2021

Megawatt said:
A couple of the wires determine what RPM’s you want it to run. The problem is that we don’t have a diagram to tell us what wire does what.

If you zoom in on the photo of the label it tells you which wire is which.

kwinch · Sep 30, 2021

I hooked up 110v wires to common and low speed and it works. I think I'll attach a box on the side with a Hi-Med-Low switch.

ColinACJL · Sep 30, 2021

kwinch said:
I've got an old furnace fan I kept the last time mine was replaced. I'd like to use it for various purposes. It has a red, black, yellow and orange wire. Also a purple going to/from I'm guessing a capacitor on the side and a green ground wire. Can I wire it up to be used on 110v ? I have 220v available if required. Also how would I control the speed? I'm guessing it had various levels.

View attachment 90574

Two problems, you will need a step down transformer and the motor is designed for 60Hz, so the magnetising current would be higher causing saturation. It's not worth the hassle.

westward10 · Sep 30, 2021

He is in the States.

kwinch · Sep 30, 2021

You guys are not??

Any idea what you call the kind of switch I need? It should have OFF, HIGH, MEDIUM, LOW settings and have one wire in and three out. I just went to 4 places and couldn't find one.