Electric Motor Aluminum Housing Cracking!!!

[fuzzybeekeeper]

We have an Emerald Spa that is 4 years old.  The main 2-speed motor went out 2 months after the warrenty went out (of course) and we paid $700 ($450 motor + $250 travel/labor(we live an hour from our dealer and pay time both ways!)) to have it repaired. 

The motor lasted a month and broke.  The dealer replaced it (no labor or travel this time).  It lasted a month and broke again.  I took the motor in and told them the cast aluminum housing around the shaft was broken.  They blamed it on UPS dropping the boxes and replaced the motor again but refused to install it.  They finally "sold" it to me on paper and I took it and installed it. 

It lasted 6 hours before it quit.  I sent it to the manufacturer who said the shaft was bent and sent me another motor.  This one lasted 24 hours (we actually got to enjoy our tub one night out of the last 4 months!) before I HEARD it pop.  The cast aluminum housing around the shaft is broken again.

I am at my wits end.  There is nothing in the pipe that would get in the impellers.  There is no damage to the impellers.  My smart (designs computers for AMD) son-in-law suggests that the motor is running backward and the impeller unscrews from the shaft, forcing the shaft to push out the back of the motor, breaking the housing.  (Maybe he is worth something after all!!)

What would make the motor run backwards?  I have been VERY diligent in wiring everything EXACTLY as the instructions say.

That is 4 motors in 6 months with 2 months of Christmas/Spring Break down time when I didn't pursue the problem.

Any ideas?

Fuzzybeekeeper

[wmccall]

Welcome to the forum, though I wish it were under better circumstances. We do have several tech types with a lot of experience here, so I'm betting you will get a couple of good answers that I will be curious to read.

[Jacuzzi Jim]

 You could go with another pump aqua flo, hayward as long as it matches up to what you have now fitting wise and power wise.   Not sure I buy the pump running backwards thing that would be strange, and since you used it once, it's most likely not running backwards.    Downfall is you would end up having to pay for the different pump.

[fuzzybeekeeper]

I have tried two different brands.  Both brands have reacted the same way.  Two pumps from each brand.  A total of 4 pumps with at least 3 that I have seen cracked or broken housings.  I will post photos a little later today if I get a chance.

Anyway, I will probably have to pay for a new pump.  I just can't afford to buy too many more $450 pumps without figuring out WHY they are breaking.

Fuzzybeekeeper

[Jacuzzi Jim]

 That is even stranger, have you actually looked at the impeller inside the housing for any breakage or strange marks on it?   What H,power are these? 

[fuzzybeekeeper]

They are 4.5 HP motors.   I have taken the pump assembly apart and there are NO marks or damage to the impeller or housing. 

The reason my son-in-law suggested that the motor is running backwards is that I went to get a phillips screw driver to take the pump off of the motor.  When I got back, he said he didn't need it.  He just spun the pump a couple of turns backward and it came right off of the shaft.  It is held in place by the direction the shaft spins as it runs.  If it WERE turning backwards, it would back off of the impeller and be forced out the back of the motor.

If it is breaking because the motor IS turning backwards, it doesn't make sense that a cast aluminum frame is breaking rather than small metal screws stripping out of a plastic housing.

Again, photos to follow.

Fuzzybeekeeper

[In Canada]

That does not make any sense, standard 120/240 volt motors are not phase specific and should not run backwards. 

[Spatech_tuo]

That does not make any sense, standard 120/240 volt motors are not phase specific and should not run backwards. 

Agree, the problem is not the motor running backward. The way the shaft is threaded was probably confusing to the SIL.

I scratch my head wondering what is causing this continual issue and without inspecting it first hand ...

[wmccall]

That does not make any sense, standard 120/240 volt motors are not phase specific and should not run backwards. 

Agree, the problem is not the motor running backward. The way the shaft is threaded was probably confusing to the SIL.

I scratch my head wondering what is causing this continual issue and without inspecting it first hand ...

Looking forward to the photos, this is one of the more unusual ones I've heard of in my years here.

[gadfly]

That does not make any sense, standard 120/240 volt motors are not phase specific and should not run backwards.  

It sounds as though the OP is getting replacement motors, and re-using the pump.  The motor is likely used in many applications, it could come from the factory, wired for the wrong direction.  Switching a motor to run backwards, usually just requires switching one, or two wires.

Given the number of failures, the underlying problem is not likely the motors, themself.  I wonder if the pump/impeller was damaged... either from the original failure, or the replacement installations.  Regardless, the servicing dealer should deal with in person, not just keep sending out motors.  If they have any pride, they would want to get this right.  Now on the other hand, if the son-in-law botched the repair, because designing computers does not necessarily make you a great spa tech... you might have gotten what you paid for!  

[fuzzybeekeeper]

Ok, I finally have photos.  I will post three, one in each message.

[fuzzybeekeeper]

This shows the same side but from a different view.  Notice the crack to the lower left.

[fuzzybeekeeper]

This one shows a crack on the other side of the same end.  It doesn't look like a "twisting" break.  It looks like a "straight back push".  Don't you like my technical terms?

[fuzzybeekeeper]

Sorry.  One more....showing no damage to the impeller.

[fuzzybeekeeper]

I also took the motor to our local electrical motor repair shop.  His first words to me were, "This motor has been dropped."  I assured him that it was a new motor from the factory shipped directly to me.  I had inspected both the outer and inner box for damage as I opened it.  I saw no damage.  I was VERY careful as I installed the motor and did NOT drop it.  The motor ran 24 hours before sustaining the damage in the previous photos.

I also had the original motor that "went out" last fall after running for two years.  It did NOT crack.  The spa technician who replaced it for $450 said that the capacitor was out.  The electrical repair man replaced the capacitor with the one from the "cracked" motor and brushes from a used motor in a pile...and the motor runs fine.  He charged me $15.

The motor is now installed on my hot tub and running fine.  I know it has only been 3 hours and the results are yet to be seen, but I know I didn't have to pay $450 for a new motor.

He also said that he should be able to get a new back to replace the broken one for around $35. and the cost to repair it. 

The only thing we didn't figure out is how the "cracks" occur.  We'll just have to wait and see if this one breaks.

In the mean time.....any ideas out there after looking at the photos?

Thanks!

Fuzzybeekeeper