GE Portable Air Conditioner

[variflexpghpa]

I have an interesting problem with a GE portable air conditioner made in the appliance park in Beijing. I lent it to a friend, and the friend called me that the air conditioner had died... no display ... DOA. I picked it up this evening and did some troubleshooting. I found the fuse on the main circuit board had blown. So I replaced it and when I fired it up and heard a noise similar to a motor laboring and then smelled something starting to burn. After pulling the plug, I found that the blower motor, which has dual blower wheels, one to push the cool air into the room, and the other to cool the condenser coil was hot. This was after only running it for less then a minute. I first thought that the motor bearings might be bad, but when I gave the blower wheel a spin, it had no drag what so ever. I then plugged it back in, and turned it back on. What I found is that the motor is spinning in the opposite direction of which it should. If it should be spinning clockwise its spinning counterclockwise. There is an arrow on the motor label showing that the rotation is clockwise. The motor an AC motor. I am thinking that one of the windings has grounded out and thats the problem, but I was wondering if one of the resident experts here would agree or if there is something else causing the problem. I am sure that the cost of this motor, if its the problem is more then I paid for the airconditioner new.

Thanks

 

[tolivac]

Does the fan-blower motor have any start-run capacitors with it-If those are bad that could cause the motor not to start properly.Start caps are usually in large black plastic tubular cans-Run caps are usually in metal oval or rectangular cases.Handle either with care-they could hold a charge even with the power off.Is there any start relays in the unit for the blower motor-if this is bad it could cause your porblems.

 

[tolivac]

Another question-how old is this unit-if its relatively new-your problem could be fixed under warranty.

 

[Cybrvanr]

some electronically controlled appliances don't use start and run capacitors, but instead use timed relays to change the windings. Contrary to popular belief, a starting capacitor doesn't give the motor a "jolt" to get it going. What happens is that when a motor starts, the capacitor is discharged. Electricity will flow through the starting capacitor while it is charging and then through the starting winding in the motor. Once the capacitor is fully charged, current tapers off and stops flowing. This tyically only takes about a half second or so to occur.

With the advent of electronic controls and such, transistors and relays can switch on a starting winding for the required half second or so to get a motor running. A few semiconductors and some ECM programming are much cheaper than huge oil-filled capacitors...go figure! With that being said, you could be dealing with a failed ECM, especially since you said the fuse blew on the ECM. Chances are, it was one of the big power-handling transistors or relays on there that burned out or shorted that handles the startup switching. A multi-meter with a semi conductor tester will tell you for sure. They will either beep quick for a good transistor, beep continuously for a shorted one, or not beep at all for one that has opened up.

These transistors are usually rather inexpensive, in the under $5 range. The trouble may be in trying to find one. Using the TCE / SK transistor cross reference, or the NTE one, you can probably find a generic equivalent you can order from an electronics supplier and get the thing back working, or if you still have electronic shops in your area, you may even be able to purchase it off the shelf! This will be MUCH cheaper than buying an new ECM board for your AC unit!

 

[tolivac]

The cap in the start winding is used in conjunction with the start winding-to initiate a phase change between the start and run windings-create a twisting magnetic feild to get the motor started-once the rotor is turning-the run winding can sustain the rotation provided the motor doesn't get stalled to the point the start winding and cap is engaged again.Electrolytic start caps can only withstand so many start cycles in a given period of time-they will overheat VERY quickly if the motor is started too many times-or if it is stalled where it cannot get back up to speed.The semiconductor devices being used to start motors is interesting-Instead of a transistor figure the device may be a Triac-these could initiate the phase change in the start winding like the cap would.Like power transistors Triacs are common and inexpensive.Most electronic suppliers or perhaps Radio Shack may have them.unlike transistors Triacs operate with AC power.A small AC pulse is used to bias them to conduct.Like a transitor you can match the type numbers as mentioned in the above entry to get a replacement device.