Furnace Motor wiring to Shop Fan

Electromechanical Switches
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1

Hey All,

I got a wiring question for everybody.

I’m working on converting a three speed furnace motor into a shop fan. I’m currently stuck on the wiring for a rotary switch.

The switch I want to use is GH7283-ND Here’s the question. The motor has a neutral and the power cord also has a neutral. Do I wire both neutrals to the switch or is there a smarter way about doing this?

Thank you!

2

@CigarArmoring

You can us it in this way in the case of the speeds you would use the common for the power cord Neutral and then use the 1, 2, 3, and 4 positions to change the speed of the fan to fixed value speeds. You would need to add more to the outputs of the switch to get the other speeds however it can be apart of the overall setup.
The below is a diagram for the 12pin version however you would be looking at just the first 4 positions + the common your switch has.

19001-04UL example
19001-04UL example624×414 49.5 KB

3

@Nathan_2268

So very very unfamiliar with electrical work.

So let me see if I get this right.

Motor:
3 speed wires - red (low) , blue (med), black (high), and white (neutral)

Wall Wire:

White, black, and ground

In the rotary switch, as you indicated. Neutral motor goes to #1, neutral wall wire goes to #12.

Red, Blue, and Black (I assume) would go to #2, #3, and 4-wege-schalter

Black would go to the center pin on the rotary switch.

Right? Or am I completely off. Also, assuming I have a 3 speed/4 position would the wiring be the same?

Thanks!

4

Hi CigarArmoring,

Assuming that your motor’s wires are as you describe, then the following should work:

  • Tie the motor neutral wire directly to the wall neutral wire (this is the return for all settings)
  • Tie black (hot) wire to “12” - the common point (the switch connects one of positions 1-3 to this point, depending on switch position)
  • Connect red, blue, and black motor wires to 1 - 3, respectively, for increasing speed
    image
    image631×351 27.9 KB

With this configuration, current will travel from your wall hot wire into the common switch contact, out the contact selected by the switch, through your motor, and back to the wall via your neutral connection. If your switch is pointing position 12, then the motor would be off.

Be sure to either place a fuse inline with your hot wire or use an appropriate breaker (or both) for safety.