new evaporator cooler motor overheats

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AV ELECTRIC

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did not see a troubleshooting forum so i elected to post here replaced an evaporator cooler motor 115 volt dual speed high and low old one burned up receptacle replaced motor and receptacle the motor is half horsepower.

when motor is turned on high speed or low the rpm is the same and motor over heats and trips the thermal overload tried different circuits same rresult

this is in a residence rural location 200 amp service 1987 challenger service

the pump for the cooler works fine the fan and belt seem to work freely cranking by hand and actually removed the belt and let motor free spin and still seemed to overheat but did not trip overloads but of coarse i am only running it for a short duration no problem in the rest of house no
flickering or unstable voltage no burned up neutrals in service

could there be a problem with the service voltage is good 120 volt no drop when running the unit it almost seems like the motor is acting like it is
running at a lower voltage but i am not seeing it on the meter and like i said tried multiple circuits same result

any thoughts would be appreciated
 
What is rated current, and what is actual current?

You said this is belt drive blower, did someone change anything recently?

I had similar call one time for an exhaust fan in a bar and of course one of the regular 4:00 PM customers is good friends with the owner and replaces motor for him (probably for beer), and they can not keep new one from overheating. I look at it and see there is a new sheave on the motor - couldn't get the one off the old motor or different shaft size or something I don't remember anymore, but the local hardware store did not have same diameter - larger diameter was chosen and just was too much speed and results in too much load.:slaphead:

edit to add: make sure you have motor rated for correct voltage or that you are connected for correct voltage if dual voltage.
 
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did not test for currant probably should but label said 4/8 high and low i presume

never seen this one its not rocket science maybe blame a neutral under load but tried multiple circuits different neutral same results could everything else work fine in the house but a motor of this size doesn't and only a half horsepower
 
Many of these motors are PSC motors and the run capacitor is ordered separately, if that is the case is the cap good and the correct value?

If dual speed make sure there is not a control issue where it is energizing both speeds at same time - that will not work.
 
no start capacitors same motor as original which appears to have done the same thing which burned up the receptacle home depot motor designed for evap coolers changed many never seen this but its probably something i am missing would not be the first time but when its something so simple install new motor have a nice day
 
AV ELECTRIC said:
no start capacitors same motor as original which appears to have done the same thing which burned up the receptacle home depot motor designed for evap coolers changed many never seen this but its probably something i am missing would not be the first time but when its something so simple install new motor have a nice day
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The last one I had a problem with doing exactly what your describing was what kwired mention in the post above, if both high and low windings are energized at the same time it will buck the windings, of two I ran into one had a bad switch that was fried and would not turn off the low winding when put into high, the other one had a bad relay on a furnace that did the same thing, so make sure both windings are not energized,
 
hurk27 said:
The last one I had a problem with doing exactly what your describing was what kwired mention in the post above, if both high and low windings are energized at the same time it will buck the windings, of two I ran into one had a bad switch that was fried and would not turn off the low winding when put into high, the other one had a bad relay on a furnace that did the same thing, so make sure both windings are not energized,
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try unhooking the low speed wire and just hook up the high and see if that fixes it, then swap high for low and see if it is ok, if so it is the switching method that is a problem.
 
yep tried to individually hook up low speed and high separately same result might have to get an exorcist

can cycles be decrease at the service coming in which could affect this i know im reaching for something and 99 percent of most things have a simple explanation but i guess that would not explain everything else working just fine i guess taking the motor outside of the source to another location and hook it up and see what happens this is the second new replacement but you never know could be a bad batch motors

this is for a friend who needs some help cooling there house living in the desert so time is not a factor as far as money is concerned
 
kwired said:
What is rated current, and what is actual current?

You said this is belt drive blower, did someone change anything recently?

I had similar call one time for an exhaust fan in a bar and of course one of the regular 4:00 PM customers is good friends with the owner and replaces motor for him (probably for beer), and they can not keep new one from overheating. I look at it and see there is a new sheave on the motor - couldn't get the one off the old motor or different shaft size or something I don't remember anymore, but the local hardware store did not have same diameter - larger diameter was chosen and just was too much speed and results in too much load.:slaphead:

edit to add: make sure you have motor rated for correct voltage or that you are connected for correct voltage if dual voltage.
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I vote for the sheave size. The he sizes of the sheaves makes a big difference in the load. I found that when I tried to take and older belt driven furnace squirrel cage motor and increased the speed of the fan which had a sheave that I could adjust and I was astounded at how much extra load there was when I increased the speed of the fan even slightly.
 
hurk27 said:
The last one I had a problem with doing exactly what your describing was what kwired mention in the post above, if both high and low windings are energized at the same time it will buck the windings, of two I ran into one had a bad switch that was fried and would not turn off the low winding when put into high, the other one had a bad relay on a furnace that did the same thing, so make sure both windings are not energized,
Click to expand...

I'm going to vote for this (and kwired's original post), because it was mentioned in the initial post (below) that when either speed is selected, the motor speed does not change. That's exactly what would happen if the speed select switch contacts were welded closed. You would be energizing both sets of windings and the higher pole count, the low speed, would prevail as far as the speed, but the windings would overload. If it was a sheave issue, the speed would change, but THEN it would overload BECAUSE the speed changed. If the speed is not changing, it's not a sheave issue.

AV ELECTRIC said:
when motor is turned on high speed or low the rpm is the same and motor over heats and trips the thermal overload tried different circuits same rresult
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yeh these motors are really cut and dry internal thermal overload protection which protects the motor and working well anything else on the circuit works good the pump works great

havent heard anything today maybe thats a good sign its amazing so much time on something quite elementary

i had an easier time troubleshooting a control panel for 2 air compressors and dryer system for a car dealership the other day

maybe it magically repaired itself but i anticipate a call this evening if so i will bring that motor to my place and plug it in and see what happens if it works i have my answer
 
the mystery is solved put in the old motor worked just fine

it appears a bad batch of motors from china thats where they were made

thanks everyone on this magical mystery tour they are back to cooler days
 
AV ELECTRIC said:
the mystery is solved put in the old motor worked just fine

it appears a bad batch of motors from china thats where they were made

thanks everyone on this magical mystery tour they are back to cooler days
Click to expand...

Maybe I missed it but why was original motor taken out in first place?
 
owner removed it because he had it plugged it into a surge suppressor that burned up he thought the motor was at fault as we know those cheap ones dont handle small loads very well so he bought a new motor

he is ordering a new motor american made just in case there maybe a problem with this one hope he has better luck with made in america
 
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