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-   -   Seized Motor Trane XE 70 (http://www.diychatroom.com/f17/seized-motor-trane-xe-70-a-31903/)

arete01 11-15-2008 09:11 AM

Seized Motor Trane XE 70
 
I have a Trane XE 70. When it was time for the fan to kick on the motor would seize, making a loud humming noise, and in turn the fan would not rotate. I lubed the shaft and then the fan was able to rotate. But, then it would seize again. Now I am not getting any noise or rotation. Do I need to replace the motor or is the any other alternatives? Any insight would be greatly appreciated.

hvaclover 11-15-2008 09:58 AM

Could be you fried the motor completely now. But check the capacitor just to be sure. It just might need a new capacitor only, but chances are the motor is gone.

Try the cap and see what that does.

Just curious, how often do you change filters?

arete01 11-15-2008 11:22 AM

Hvaclover Trane XE 70 Seized Motor
 
I took a capacitor off of another Trane XE 70 that works and I still had the same result. So, you think I need a new motor?
And I change the filter about once a month.

hvaclover 11-15-2008 12:41 PM

Quote:

Originally Posted by arete01 (Post 185285)
I took a capacitor off of another Trane XE 70 that works and I still had the same result. So, you think I need a new motor?
And I change the filter about once a month.


Where'd find the other Trane. I have an idea but i would just like to hear it from you.

But for farts and giggles why don't you check the voltage to the motor just to be safe before you buy a new one.

Marvin Gardens 11-15-2008 02:34 PM

If you spin the motor by hand and it makes noise or is hard to turn my guess would be that your motor is fried.

kennzz05 11-15-2008 02:39 PM

if the capacitor is the same size(mfd) rating and it was on a known good motor than its motor time should be in the 50 to 65 dollaar range

arete01 11-17-2008 09:34 AM

Hvaclover Trane XE 70
 
To your question where I found another Trane. I have a small apartment complex and there two Trane's right next to eachother. Since they are right next to eachother should I put the blower from the one that works in the other one to make sure that it is the motor?
I will admit. I am a newbie at this.

Marvin Gardens 11-17-2008 09:56 AM

Quote:

Originally Posted by arete01 (Post 186266)
To your question where I found another Trane. I have a small apartment complex and there two Trane's right next to eachother. Since they are right next to eachother should I put the blower from the one that works in the other one to make sure that it is the motor?
I will admit. I am a newbie at this.

That would more than likely work if they are the same model. It would be a great diagnostic tool to tell you if the motor is bad.

beenthere 11-17-2008 05:05 PM

If you had to oil the motor to get it to work.
It most likely either permanently opened the internal over load, or fried a winding.

Pulling a motor from the other unit, is just more labor then needed, for the same end result.

beenthere 11-18-2008 01:07 AM

Quote:

Originally Posted by bookfly (Post 186679)
Try the cap and see what that does.

In post #3 he said he put a cap from a working unit in, and the motor still doesn't work.

jehiatt 11-27-2008 06:04 PM

If the fan is still easily movable and it doesn't operate- replace the start capacitor with a new one. If no good results.
Replace the motor.

hvaclover 11-27-2008 06:18 PM

Quote:

Originally Posted by jehiatt (Post 190852)
If the fan is still easily movable and it doesn't operate- replace the start capacitor with a new one. If no good results.
Replace the motor.


Since when do PSC motors use start caps? A start cap is used on a high starting torque split phase motor that have to start under a load.

That means the start cap only stays energized long enough to get the motor rolling and he relay drops out the start cap (or the star cap would blow) as the run winding takes over running the motor.


A PSC motor uses a RUN cap which stays energized all the time the motor runs and it also keeps the start winding in the circuit along with the run winding to make the motor more efficient, and the cap causes a phase shift in the current that stops the windings from burning up as they run at the same time.

micromind 11-29-2008 11:52 PM

A PSC motor is actually an open-delta 3 phase motor that's designed to run on single phase power. It has two windings, both stay energized continuously. The capacitor causes a phase shift between the two windings to simulate 3 phase power.

This is why a PSC motor has very low starting torque, but very high efficiency.

You can 'make' a PSC motor out of any 3 phase motor and a static-type phase converter. It's the same principal, and operates the same way. Low starting torque, high efficiency.

A capacitor-start single phase motor is completely different. The starting capacitor causes a phase shift in the start winding, but is cut out of the circuit when the motor is at about 1/2 speed. In this case, the capacitor and the start winding team up to cause high starting torque, but they don't have any effect on efficiency. Some capacitor start motors are also capacitor run. These are the best of both worlds, the start capacitor provides high starting torque, and the run capacitor provides high efficiency. The only place you'll find this type of motor in a HVAC system is the refrigeration compressor, not the blower or fan.

In a PSC motor, if the shaft spins freely by hand, and you have a known good capacitor, and the voltage is close to what's stated on the nameplate, and it still doesn't run, there are only two other possibilities I can think of.

The first is that one or both of the windings are burnt up.

The other is that the bearings are so sloppy that the rotor isn't centered in the stator. This will cause it to hum, and try to turn, but it can't because it is fighting against itself.

Sometimes you can replace bearings, sometimes not. If there is the slightest evidence that the rotor has made contact with the stator, the motor is destroyed.

Rob

arete01 12-01-2008 07:35 AM

Rob,

Thank you for the feedback. I installed a new motor and she is running great. Thanks again.
I do have another furnace issue. I have an older gas furnace and the pilot light will not stay lit. I replaced the thermocouple and that did not work. Any suggestions. I am a rookie when it comes to furnaces.

Thanks,

Arete01

hvaclover 12-01-2008 09:40 AM

Sounds like a weak operator in the valve. Means a new valve.


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