The object of this test is to determine the real world operating temp of a pool pump motor

Motor  "A" is a non powered reference
motor used as a control sample for the
ambient temperature as motors will gain
heat due to solar radiation

This test was done Aug 12, 2013
at Coral Springs FL
Ambient Air Temp = 92F

Pump was a Hayward Super Pump
1 HP with SP2607 impeller

Motors were
AO Smith / Century UST-1102
Emerson / US Motor  EUST-1102


We installed a ball valve in the pump
discharge to allow the pump to build
12 psi pressure, as most pools have some
friction loss due to filter & piping

A

AO Smith / Century
UST1102
1 HP  1.1 SF
Max Amps  7.5 @ 230 Volts

The unpowered control sample had a temperature of 104 F

The AOS/ Century show a case temp of
165 degrees F



165 - 104 = 61 degrees rise above ambient

After 2 hours, the motor amp draw stayed
at:  7.25  which is below the 7.5 max load
indicated on the motor nameplate

7.25 Amps

61 Degree F Temp Rise
Above Ambient Temp

Hayward  pump with a
EMERSON / US MOTOR  EUST-1102

The control motor ambient temperature
was 96 degrees F

The name plate on US motors

It is somewhat confusing as it says
1.0 HP  SF 1.0   6.8 A@ 230v

But if you look the last line is says

1.25 SF  7.5/ 15.0 AMPS

We shall assume this is a 1 hp motor
with a 1.25 service factor with a max
load amp rating of 7.5 @ 230 volts

 

The  Emerson/USmotors had a case temp
of 161 F

161 - 96 =  65 degree F rise above ambient

Emerson / US Motors stayed at  6.4A @230V

EUST -1102
6.4 Amps @ 230 V
65 Degree F Temp Rise

POOL PUMP MOTORS
OPERATE  UP TO 65 DEGREES F ABOVE
AMBIENT TEMP

This info applies only to this specific equipment
Other products may yield different results

 

 

How Hot Do Pool Pump Motors  Get?

The Bottom Line:  We find that most pool pumps run as high as 165 to 195 F
when the ambient temp is 90 to 96 degrees F

UPDATE JULY 2018
If your motor is very hot, & cycles
on and off all day, you may have a
broken cooling fan

Click Here For Information

This method of measuring the case temperature is for relative comparisons only, as this is the way most homeowners determine the operating temperature of their motors.
An accurate scientific method would measure the winding temp by inserting a thermocouple or measuring the cold and hot resistance of the windings