I am replacing a GE motor with an equivalent Mars motor, they are same fitting size, HP, RPM etc. and volt range 208-230. The wires are different though:

  1. The old motor had orange, blue, and black
  2. The new motor has four wires, brown, brown/white, yellow and black.

the black and yellow have raw tips, and the brown and brown/white wires have female knife-blade connections.

I am wondering which wires to equivalently hook up. I'm thinking obviously the black is common, but beyond that I don't know.

old motor orange and blue connection to - capacitor maybe? black connection to terminal (in back) new motor label new motor diagram new motor wire ends shown

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    Can you include a better photo of the wiring diagram on the new motor? Typically, Brown and Brown/White go to the run capacitor. Black and Yellow are line (L1 and L2) – Tester101 Aug 13 '16 at 19:51
  • See answer I posted below - yes, you're correct on both and old motor is in trash. But answer below also clarifies what I didn't understand about the 4 vs. 3 wire setup and why the change. – Oliver Williams Aug 13 '16 at 20:33
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    It doesn't hurt to swap the cap. Capacitors have a finite service life, and "wear" both in service and in storage. A well tended motor can run indefinitely, especially an induction motor. – Harper - Reinstate Monica Aug 13 '16 at 21:28
  • what does line mean? i have the motor you had, does orange and black both go to hot if so is there a neutral? or is orange neutral and black hot or vise versa? – james flores Dec 30 '16 at 5:54

Figured this out! I hope this answer posted here helps someone else. The real topic here is "converting from a 3 to 4 wire motor.

First of all, a shout out to Solar Supply, Inc. in San Marcos, TX for matching the Mars 10204 motor with my GE for about 85 bucks.

The first thing he did when I got it was grab a capacitor and add it to the box. I thought, "I wonder why, I already have one?" Well, now that I compared both diagrams it makes sense.

The old motor's orange line was connected to one of 3 leads on the capacitor. From that line I noticed that there was a YELLOW line that went to the terminal block. I deduced that orange was analogous to yellow on the new motor. Black? That was easy, at least one thing was obvious.

That leaves the brown and brown/white pair. It finally dawned on me that these were to go on the new, separate capacitor that the guy at Solar gave me. I'm assuming that having a dedicated capacitor for the fan motor is an overall improvement in safety and integrity. I suppose it would be theoretically possible to join the brown and brown/white wires to the old capacitor, but Murphy's law said that a 50% chance of getting it wrong is optimistic.. by so doing you're essentially joining one leg of the capacitor wires to the line voltage, and there must be a good reason why the capacitor is now separate.

The small green ground wire was a bit of a mystery but I just added it to the mount screw attaching the motor to the grill. Here is the diagram which should make everything clear:

old vs. new comparison

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