Voltage and Pump Temps

[mattsauber]

So, I just had my pump motor burn out on me and I have just replaced it. I have wiring for 230v but am currently configured to use 115v. I would like this new motor to not run as hot at last longer than the last one.

My question is: if I convert to 230v will my pump run cooler?

 

[mas985]

No. Power consumption and thermal performance of the motor is exactly the same. The only difference is where the supply wire connects to the terminal block of the motor. The current with 115v is twice as high in the terminal block (as well as the supply wire) but after the terminal block, the currents and voltages are exactly the same in each part of the winding.

However, the failure of your motor may have had nothing to do with voltage. Exactly how did the motor fail? More details than just "burn out".

 

[Bill in SoCal]

How "hot" your motor runs is determined by the amount of current (amperage) it is drawing. If you size the motor appropriately (based upon the size of your pool and your usage) then it will run as "hot" as is "normal" for its usage and environment. A 1 HP motor set up for 230V will use or draw less current than a similar 1 HP motor set up for 115V. In the world of electricity and motors 1 HP = 746 watts of "power". Power (P) = Amperage (I) X Voltage (E). So using my example of a 1 HP motor, at 115V it would be drawing 6.5 amps (746/115 = I) vs. at 230V it would be drawing 3.25 amps. More current (amps) = more heat generated (all else being equal). Heat is the enemy of motors. My calcs are rounded and approximate. Utilities bill for the watts used, so you would pay the same for usage of each motor, but the higher voltage rated motor would generate less heat. I would suggest you run your motor at 230V if you are setup to supply it with that. Sorry if the answer got sort of technical, but that's electricity for you........

 

[JohnT]

I'd go for 230. The higher current needed at 115 leads to more voltage drop in the wiring, and that could cause the motor to run hotter.

Either way, the motor is designed to run at the elevated temps it experiences running long hours during the summer so it shouldn't make a difference in the life.

 

[mas985]

More current (amps) = more heat generated (all else being equal).

Not really because the current is split right after the terminal block in the motor so in reality, each winding wire within the motor has exactly the same current with 230v vs 115v. It is only at the terminal block where the current is double for 115v. See schematic below: