- Thread starter TomAtlanta
- Start date

Or if you want to understand that, 110v is only a problem when you cheap out

I am not sure what you say is true.. But the cheaper the pump, the shorter their life span.. And my guess is that the average pool owner with a 120 volt pump will try to replace it with the cheapest pump they can find..

Are you saying a pump that is designed to run on 120 or 240, will burn out faster when run on 120 volts?? If so, I have never heard that before..

Thanks,

Jim R.

I read that somewhere on this forum. I don't understand enough about electricity and motors to explain it very well, but someone said the pumps ran hotter at 120. I will try to find a link to that discussion.Are you saying a pump that is designed to run on 120 or 240, will burn out faster when run on 120 volts?? If so, I have never heard that before..

Everything being the same everything is the same

If the mains supply wire is sized appropriately, the current going through the winding's is exactly the same wired for 240v vs 120v. However, if the wire or cord is undersized, this can lead to a larger voltage drop for the 120v case than for the 240v which can lead to a higher current draw for 120v (and higher motor temperature).I read that somewhere on this forum. I don't understand enough about electricity and motors to explain it very well, but someone said the pumps ran hotter at 120. I will try to find a link to that discussion.

So why do they make the pumps work on both 120v and 240v ? Why ever use 240v if there is no advantage?

But in reality the choice is usually more about what is available.

There is one more thing to consider. If your pump failed due to a motor issue, it could be caused by excessive voltage drop. The general rule of thumb is no more than 5% voltage drop (under a load). So if you know someone with a voltmeter you could ask them to measure the voltage at the pump when it is running. If the voltage is any lower than 120V - 5% or 114V, then you could have more heat production, less efficiency, and premature failure of your pump motor.

Residential voltage can be either 110/220 or 120/240 or 108/210. It really depends on the local power grid and how and where the transformers feeding your house are tapped and located. These voltages are also nominal voltages. What is actually making it to the power panel in your home needs to be verified. If your panel is starting out with a lower than average voltage allowing for an additional 5% drop before it gets to the end device can really cause issues.

At the end of the day there is no real tangible difference in motor design or life span for a 110v or a 220v motor. As long as the motor is fed by a properly designed circuit that can handle the current draw of the motor.

The reason 110v motors seem to fail more often is simply that there are more of them and they are often plugged into any plug you can find without any consideration for weather or not the wiring to that plug can handle the motor. 220v motors seem more durable because there are far fewer of them in a home and they are almost always installed on circuits specifically designed for the needs of the motor.

Nope. Exactly the same. Amps X Volts = watts. Look at the plate on a dual-voltage motor. It'll show two amperages-- one is half the other. It'll also show two voltages -- one is twice the other. It cancels.

220v at 3.5 amps

110 v at 7 amps

Note hp = watts, you could say a 750 watt pump and it means the same as a 1 hp pump

Casey,

220v at 3.5 amps

110 v at 7 amps

Note hp = watts, you could say a 750 watt pump and it means the same as a 1 hp pump

Sorry, but it is not half the amps, because each leg of the 220 pulls 3.5 amps each for a total of 7 amps..

Jim R.

If you measure each leg of 110, I believe it's been awhile, each leg will pull 7 as well

I now realize that what I posted may have caused some confusion so let me explain further.If the mains supply wire is sized appropriately, the current going through the winding's is exactly the same wired for 240v vs 120v. However, if the wire or cord is undersized, this can lead to a larger voltage drop for the 120v case than for the 240v which can lead to a higher current draw for 120v (and higher motor temperature).

There are two poles in a single speed induction motor. Each pole is a separate winding. When wired for 240v, the two winding's are fed in series so there is effectively 120v across each of the poles. When wired for 120v, the two winding's are fed in parallel with 120v across each of the winding. So in both cases, the same current is traveling through each winding and there is the same voltage across each of the winding. But because the 120v wiring is in parallel, the draw from the mains is 2x that of the 240v case.

The hp rating of the pump does not directly translate into how many watts it uses.Note hp = watts, you could say a 750 watt pump and it means the same as a 1 hp pump

For example a 1 hp full rated Whisperflo pump will use close to 1,650 watts, which is about double what you would expect.

First, you have to look at the total hp, which is the rated hp x the service factor.

A full rated 1hp WhisperFlo has a total hp of 1.65 hp.

The total hp is the delivered hp, which is the total power used x the efficiency.

For induction pump motors, the total hp x about 1,000 will give you the total power used.

This is in contrast to a gas heater, for example, where the rated power is the total power used and the delivered power is the total power used x the efficiency.

The motor can say 20 how it still will draw close to 1 hp, except for efficiency