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-   -   Trane XE90 blower no longer spinning but making big noises (http://www.houserepairtalk.com/f8/trane-xe90-blower-no-longer-spinning-but-making-big-noises-13051/)

vgs8606 01-22-2012 09:11 AM

Trane XE90 blower no longer spinning but making big noises
 
Blower will spin freely and smoothly when there is no power applied to it. I can watch the blower and it does want to spin in the correct direction but it is only crawling, like one degree every few seconds. Trying to push it by wooden stick shows lots of resistance as if there is a giant magnet holding it back. Start capacitor was replaced but that had no difference in the symptoms.

I checked the motor stator windings and they all checked out (4 - 6 ohms). I checked the voltage coming out of the controller when it commands the motor to spin. No load voltage is 120VAC and when the motor is making the noise, it is at 118VAC. I also tried all four leads and they all noises, some more some less.

When the motor spins freely without power, there is NO axial or lateral play. When the power is applied, I do not see any shift. This tells me that motor is mechanically sound. I am at a loss as to what can electrically go wrong with rotor on this type of motor. I am under impression that they are pretty much bulletproof.

I am concluding that I need new motor and motor only i.e. the fan assembly is fine (because it spins freely without power) and controller is fine (because it is providing 120VAC to the motor).

I would like to apply direct 120VAC to the motor but I do not like the unsafe aspect of it. Given that I have already measured the live voltage to the motor coming out of the controller at the junction and it is showing 120V, there is no logical reason to think applying direct wall power would make any difference. Can you come up with a scenario under which this assumption would be wrong?

As you can imagine, the house is very cold. I already had a technician come in and the motor is on the order. But I definitely want to make sure putting the new motor is going to fix it. I just can not take "oops, we need more parts and they need to be ordered" saga anymore.

Trane XE90 forced hot air, installed YR2000

Thanks,

paul52446m 01-22-2012 04:40 PM

Quote:

Originally Posted by vgs8606 (Post 66849)
Blower will spin freely and smoothly when there is no power applied to it. I can watch the blower and it does want to spin in the correct direction but it is only crawling, like one degree every few seconds. Trying to push it by wooden stick shows lots of resistance as if there is a giant magnet holding it back. Start capacitor was replaced but that had no difference in the symptoms.

I checked the motor stator windings and they all checked out (4 - 6 ohms). I checked the voltage coming out of the controller when it commands the motor to spin. No load voltage is 120VAC and when the motor is making the noise, it is at 118VAC. I also tried all four leads and they all noises, some more some less.

When the motor spins freely without power, there is NO axial or lateral play. When the power is applied, I do not see any shift. This tells me that motor is mechanically sound. I am at a loss as to what can electrically go wrong with rotor on this type of motor. I am under impression that they are pretty much bulletproof.

I am concluding that I need new motor and motor only i.e. the fan assembly is fine (because it spins freely without power) and controller is fine (because it is providing 120VAC to the motor).

I would like to apply direct 120VAC to the motor but I do not like the unsafe aspect of it. Given that I have already measured the live voltage to the motor coming out of the controller at the junction and it is showing 120V, there is no logical reason to think applying direct wall power would make any difference. Can you come up with a scenario under which this assumption would be wrong?

As you can imagine, the house is very cold. I already had a technician come in and the motor is on the order. But I definitely want to make sure putting the new motor is going to fix it. I just can not take "oops, we need more parts and they need to be ordered" saga anymore.

Trane XE90 forced hot air, installed YR2000

Thanks,

Can you spin the blower by hand when you have the power on it?
It sounds like it your Start capacitor is bad again. When you have them change the motor make sure you put a new capacitor to match the new motor. One other thing that can mess a motor up is, if for some reason two winding's of the motor get hotted up at the same time. Paul

vgs8606 01-22-2012 04:56 PM

The motor can not be spun by hand when the power is applied to it. As far as I can determine of the four spades coming out of motor, two are parked, one is for heat and the other is for cooling. Controller provides current to only one at a time.

I finally tred to hard-wire motor from the wall power and it does not want to spin. Something internal to the motor has gone bad.

vgs8606 01-23-2012 06:15 PM

Motor needed to be replaced. The new motor is quiet.


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