Hot motor

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- eversfm
  
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posted
18 years ago

Sun, Sep 18, 2005 5:45 PM

I have a 1 HP F&W water pump motor that seems to start and run okay on the bench. However after a few minutes it begins to feel hot and does have a hot smell. I've not let it run long enough to see if the thermal switch will kick it off. How can I test the windings with a multimeter? I have several motors to check- is there a routine troubleshooting procedure I can follow. I've looked all over and I haven't found any. But I would like to be able to check capacitors, centrifugal switches, shorts and grounds. I hope this is the correct group. Thanks, Lloyd

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posted
18 years ago

Sun, Sep 18, 2005 5:52 PM

I had to troubleshoot a 25 HP irrigation pump with those symtoms once. It was a mouse nest blocking air flow. Sometimes it isn't electrical.

Good luck

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- Ignacio SimÃ³n Yarza
  
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posted
18 years ago

Mon, Sep 19, 2005 6:37 PM

Firstly, measure the ohmic resistance between 2 phases being the motor at room temperature and check whether cables are made of cupper or aluminium. Then let it work and at the moment you think it is getting too hot, disconnect it and measure resistance again: Th = [(Rh/Rc ) x (K + Tc) ] - K

where: Th = hot temperature

Tc = cold temperature

Rh = hot resistance

Rc = cold resistance

K = 234.5 (a constant for copper)

you can have a look at:

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Once you have the temperature rise, check out the insulation class of the motor, i.e. F,H...

Example: class F allows at much as 155ºC temperature.

Best regards,

Ignacio Simón

Mech&control engineering.

Comparing both values you can have an idea of the mean temperature rise with the formu escribió en el mensaje news: snipped-for-privacy@o13g2000cwo.googlegroups.com...