110 v vs. 220 v

[Jerry]

Given the option, is it more economical to run a pump on 220 volts?

 

[JohnT]

Not really. The primary advantage of 220 over 110 is that you can use smaller wire for the same pump capacity on 220, both for the power feed (and for the windings if it is a 220 only motor).

With the price of copper, this can be a significant savings.

There are some small efficiency gains due to the change in resistance with heat, since the higher current 110 generates more heat for the same load, but not enough to worry about on an AC motor in this application.

 

[JasonLion]

To my eye, 220v is better, but it doesn't make much difference for smaller motors (less than 1 HP). Even though there isn't any difference in inherent efficiency, there is often a difference in practice, especially with long wiring runs between the electrical panel and the pump. JohnT is correct that you can compensate for this by using larger wire, but this is not always done correctly in practice, especially with motors over 1 HP where the required wire size is very large and difficult to work with.

Even though there doesn't need to be any difference in efficiency, if you look at real world installs of larger motors, you will generally find that, on the average, the 110v installations lose more energy in the wiring than the 220v installations. If your motor is under 1 HP, I wouldn't worry about it. But larger motors there can be some practical advantages to using 220v.

 

[mas985]

I agree with Jason and John. The only difference is outside of the motor. Inside the motor windings, the currents are nearly identical. The terminal block in the motor has to carry twice the current in 110v setup but they are usually made to do so although some techs have claimed that they have seen more failures in a 110v configuration.