Spa Motor Temperatures Seem Excessive

[SpaMon345]

I recently replaced a wet end on my east spa motor, matching it to the 2HP wet end that was previously installed.  It was a learning experience for me, as I have not dealt with motors or pumps much at all.  I mistakenly got a side discharge instead of a center discharge replacement wet end, however my plumbing reaches. The wet end I purchased is a Waterway 310-0810.

Running both spa motors on high speed after about 30-45 minutes, using an infrared thermometer the west motor housing reached a temperature of 135F-140F and the east motor housing reached 151F.  Both of these seem excessive, but especially the east motor.  I have spun both motors by hand, and there is no binding in either one - they both spin relatively easily.

Both motors are the same age - about 11 years, and there has been just moderate use of the tub all those years. The breaker for the spa is normally left off for week or two at a time, as I will occasionally run the spa for a few minutes.  There is no sign of water damage to either of the motors.  Also the motor labels are not browned at all.  There is some airflow going through the motors, and none of the motor ventilation holes are blocked.  There is no excessive vibration, and there are no electrical smells.

It is possible that the east motor always ran this hot (151F), as I have never felt them before after running the spa for a long period of time.  I would say that there has been no change to the west motor so It must have always run 135-140F.

The motors are:
Model: Emerson T55CXBMM-986
Flo-Master CP by Agua-flo
Model # 03621000-2
Code 06093

Are these temperatures OK / normal?

[Dr. Spa]

normal

[SpaMon345]

OK thanks. At what housing temperature should I become concerned?

[dg98adams]

Not sure but I found this online.... Most residential pool pump motors have insulation ratings of Class B which is good to 130C or 266 F

A marked increase in temp of an OEM motor is a sign of corrosion or bearing failure... but from the sampling I found when I googled "spa motor temps" you seem to be in the working range.

[SpaMon345]

Thank you for the information.

[stanley9layton]

According to me, Class B or Class F insulation systems are most common in today's industrial-duty motors. Smaller sizes, say up to 5 HP, are typically class B. From 5 to 10 HP, many ratings move toward class F. That's also true of premium efficiency and inverter duty motors. Larger than 10 HP, Class F becomes more common. Beyond that, many manufacturers design their motors to operate cooler than their thermal class might allow. For example, a motor might have Class F insulation, but a class B temperature rise. This gives an extra thermal margin. Class H insulation systems are seldom found in general purpose motors, but rather in special designs for very heavy use, high ambient temperature, or high altitude conditions. Class A insulation is not used in today's industrial duty motors, though it can be found on some small appliance motors. Most residential pool pump motors have the insulation ratings of Class B which is good to 130C or 266 F. A marked increase in temp of an OEM motor is a sign of corrosion or bearing failure... but from the sampling I found when I googled "spa motor temps" you seem to be in the working range.