View Full Version : Replacing existing GE in my Goodman HVAC with a Grainger universal motor
SavinDough
Oct 17, 2011, 09:31 PM
My unit is a 3yo Goodman, Air Handler ARUF486016AA. The blower fan's center disk broke free of the fan and would no longer properly turn fan and made a lot of noise. I decided to fix the problem myself. I bought a universal motor from Grainger to replace my existing GE in my Goodman HVAC, a new cap and fan. The Old motor (GE) had the following wires, Red, Blue and Black (L,M &H) Red went to "M1" Blue to "M2" and black to "COM" all on the same circuit board, Brown and Purple which both went to the cap and the purple one had a smaller purple lead that went from the purple side of the cap to "Line" or to the "COM" of a nearby, small transformer; labeled 208-240 VAC.
The new Grainger (A.O Smith) has the same Red, Blue and Black and I wired them the same as above. Then it has Brown and Brown and white (which it says both go to cap) and a yellow wire labeled "Line", which I wired to the "COM" of the nearby transformer (power). Now, the difference being that the yellow does not touch the cap and goes straight to the power, if I'm reading the schematic correctly, that's how it should be. There is no direct connection between the Cap and the power as before. I'm assuming that there must be some sort of internal crossover in motor that sends the power to the cap. I'm not sure. What did I do wrong? Please help.
drtom4444
Oct 18, 2011, 10:45 PM
What does the wiring diagram say? It does not sound like you wired it right. DrTom4444
SavinDough
Oct 19, 2011, 08:45 AM
drtom4444: Thanks for the response. I'll try to be more clear on my wiring scheme.
Schematic on the motor shows, Red is Low, Blue is Medium and Black is High speed. I wired the Black to the same spot where black from my old GE was wired (assuming that means it's now in High Speed Mode). Location of Black is wired to a small, black plastic square on the circuit board marked "COM". Red and Blue both go to what I'm assuming are "blank, male, spade clips" (M1 and M2) on the same circuit board as black. (again, I wired them in the same positions as they were with my GE). Brown and Brown/White on the new motor, show leading to the cap, Old GE was Brown and Purple leading to cap. That is where the two schematics differ. Old GE shows brown and purple going to cap with a small purple lead, coming from purple side of cap, leading to "Line" or the 208-230vac side of the small transformer. The New motor has a separate yellow wire that shows going to "Line" and no lead coming directly from cap to the 208-230vac terminal of the small transformer. That's the only schematic difference and that's how I wired it. It ran so slowly that my unit iced up from slow return air. Also, after a couple of hours running, motor stopped. Now, technician says it shows lock up on ohm meter. Motor still spins freely, but I'm not sure if it will run at all on the other speeds or if my motor is trashed. If it's trashed, what are the odds that Grainger will "make ammends" with me and either refund my motor cost, exchange my motor or fix my motor? Thank you for all your help and advice.
drtom4444
Oct 19, 2011, 02:46 PM
You burned up the motor by wiring it wrong. Line is common and high speed is black, so yellow goes to "Com" and you wired the cap correct, but I cannot tell you where Black goes without more info. Black should go to the fan relay on the normally open contact on relay. Cap off other wires because if you energize red and black or blue and black or red you will instantly burn up motor. Remember: Yellow goes to one side of the 240 volt line and the other line is wired to Black. I don't know if Grainger will replace the motor, but they probably will. Pay no attention to the color codes of the old motor: They don't apply here. DrTom4444
drtom4444
Oct 19, 2011, 02:48 PM
One other thing: did you get the rotation right? DrTom4444
SavinDough
Oct 20, 2011, 08:20 AM
drtom4444,
Thanks again for the responses. What I know now, as a result of your advice and a few more very late nights spent researching via internet, is this: I did connect all of the motor wires to my air handler correctly. (btw: my black wire went to the fan relay circuit board; think that's what it's called) You asked about rotation in your last post. I'm going to have to say that is where my error occurred. My motor came wired CCW. On the motor, there is no directional arrow or anything other than the words, "Rot - Rev" (Rotation - Reverse, I assume). However, I didn't know that for GE and GE motor replacements (well, depending on the company making and selling the motors) when the schematic indicates CCW it is referring to viewing the motor from the side opposite the shaft and not the shaft end. So, between knowing that I was going to need a CWSE rotation, and not knowing that, while my motor was wired CCW, I thought it meant CCWSE. I was wrong. It meant the end OPPOSITE the shaft, I made a foolish error and switched the leads. That's why my motor seemed as though it was barely pushing air, why my coils froze up immediately and I can only assume, eventually why it burned up. Admittedly, a purely novice mistake.
Grainger was, however, most gracious and has agreed to allow me to return the motor. (Those guys have been both personable and complete professionals with me and I'm greatful). So, that means, that my A/C should be fixed tonight.
I do have one more question, though. My capacitor, a 10MFD +-5%, is reading 13. All the threads and videos I've seen and heard discuss decreasing in capacitance, but never increasing. Since it does say, "+ or - 5%" my guess is that I'll replace it and check the NIB before insallation, to be safe. I know I can go up in voltage, but I don't think I can go outside of the 9.5 - 10.5 MFD capacitance range. Am I doing the right thing, here? Thanks again, drtom for taking time to answer my question and steering me in the right direction.
drtom4444
Oct 20, 2011, 11:25 AM
You should always replace the capacitor when replacing a motor or you can void the warranty as well as burning up a motor. Check the size on the motor required for the new motor. 13 mfd is too much if it calls for 10, but that is a big capacitor for most motors. The blades on the squirrel cage fan point in the direction the fan is supposed to turn. The fan turns with the cups of the blades pointing forward always. If you make a "C" with your left hand your hand would go left to right with the cup of the "C" facing to the right, as an example. There are big fans like the one used to create a vacuum for wood shops that use a fan called a backward curved fan which is the opposite. I have found one turning backwards that had never worked right and reversed it by switching two wires on the three-phase motor, fixing the problem. Backward curved fans are also used on exhaust fans for restaurants, etc. but not on home air conditioners. Good luck. DrTom4444
SavinDough
Oct 21, 2011, 06:49 PM
drtom4444,
Ok, here's the final chapter of my story. When I purchased my new motor from Grainger, I also purchased the suggested capacitor, a 10 MFD, that they recommend with this motor. I hooked everything up as I explained before. When the motor did not push the air that it should have been pushing, I removed the motor and switched it from the way it was wired from the factory: "CCWLE" to "CWLE". The condition did not improve, it actually worsened. So, I switched it back to "CCWLE" and it again, was not pushing enough air. I ran it for about an hour and all it dropped the temp in my house a mere 1 degree and froze up my evap coils and the line all the way out to my condenser (2 story house). I shut it down for the night and ran it again the next day. Same low air flow, icing and disappointment. Only difference, the motor burned up, this time. Just out of curiosity, even though the capacitor was matched by them when I bought the motor, I checked anyway. Despite the fact that it was supposed to be a 10MFD, it was pushing 13, oddly enough. They don't even sell a 13. So, I called Grainger. They told me to bring the parts back for exchange. They didn't ask questions, they didn't give me the business. I took it back and exchanged both, free of charge. They gave me a new capacitor (this time I prechecked before install; 10.2 MFD, good to go). The motor may be a rebuild but I don't care. All I know is that I installed everything exactly as I had before and it worked like a dream. They told me at the store that sometimes capacitors are bad out of the box and that they can fry your motor. I'm just completely happy that I was able to fix my AC and got a new fan, new motor, new capacitor installed, for just over $230.00. Not too shabby. I would like to extend a huge thanks to drtom4444, for all of your help, advice and most of all for your taking the time to respond with your wisdom. I guess I can chalk this up to a victory for the novice. Thanks again. Greatly appreciated.
drtom4444
Oct 21, 2011, 07:03 PM
Hello,
I am glad you were able to fix your AC. I am a volunteer here and all I want is for you to be able to repair your unit without being ripped off. It seems that the main problem is the capacitor, but I wondered how you knew what the capacitance was on the capacitor. Did you have a tester? DrTom4444
SavinDough
Oct 22, 2011, 09:42 AM
Drtom444, Yes. I purchased an ohm meter that also reads capacitance. I made sure of that before my purchase, because I don't always trust what's being told to me by "experienced technicians". I know that some techs get commission or kickbacks for every job sold to the consumer. So, I expect that they naturally gravitate toward the profit and not the honest opinion. I then looked up a bunch of sites that explained capacitance, resistance etc and even host of "youtube" videos. After doing my online research and trying to discard what seemed to be mere opinion and not based on fact, I started the job. I failed to check the new capacitor before installation, simply because it was new. I didn't know how to check the motor before installation, so I didn't do that either. I'll never do that again. It was, however, a great learning process, as I didn't lose out more than an extra trip to the store. I'm very thankful for the many pros and experienced amateurs out there that dedicate their free time to assisting DIY'ers like myself, in accomplishing their tasks and not "getting ripped off". That's the big thing. This service is fantastic. I had an experienced AC tech from a local company with a good reputation, come and evaluate my system for the fall/winter season. He discovered that my run capacitor (only 3yo by the way) for my condenser had failed. He offered to replace it for $299.00. Can you believe that? The part ranges from $6.00 to $15.00 on the high side, and takes like 2 minutes to replace. Very easy to do. C'mon! I work on my cars a lot and have been a welder, pipefitter, plumber and sheet metal worker for the USN for a number of years (retired now after 26 yrs). I have a lot of maintenance on a variety of different equipment under my belt. I do have a basic knowledge of and curiosity for how things work. I can usually pick things up quickly. Sometimes, jobs that take me out of my comfort zone of mechanical or structural jobs (ie; electrical or electronics for me) can be intimidating or even frightening. But, after arming myself with some knowledge, adhering to safety precautions and not hesitating to ask questions (even if they seem like novice or stupid questions), I was able to save myself hundreds if not over a thousand dollars for the repairs that were needed. Again, much appreciation to those of you who take the time to reach out and share the knowledge with those of us who lack it. I will definitely not hesitate to come back to this and other similar sites in the future and will certainly recommend this one to others. Note to drtom4444, "you da' man". LOL. Thanks again.