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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:
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.
I ended up pulling the capacitor and testing it with my ohm meter. It was dead. I could have easily gone to the local HVAC supply, purchased a new capacitor for $30 and installed it myself. But, because I also wanted to have the pressure tested, I called in the guy who installed my furnace. He affirmed that I "did good", it was the capacitor. And because I had done most of the diagnostic work, he cut me a good deal.
In the end, the most important bit, on a 95 degree day when the humidity is 70%, a happy wife is a blissful life. ;)
Without actually being there, and not being able to see the wiring at each of the devices, it's difficult to be sure what's going on. But here's my best guess, based on past experience.
To make it easier, I've numbered the ungrounded (hot) conductors in the photo from left to right.
Why 3 and 5 are controlled by the same switch, I have no idea. Again, I can't see the room, so I have no idea what equipment you have.
If 1 and 4 are both for lights, it makes sense that a singe switch controls them.
One other thing to check, is to make sure the terminals of those switches are rated to accept more than one conductor. There should be a label on the switch that tells you what type, and how many conductors can connect.
Best Answer
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, separatecapacitor 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: