When upgrading to 2-speed pump, can I just replace the motor?

[mas985]

Waste is correct in that the motor that is different between a one and two speed pump. A two speed pump has 4-poles vs 2-poles so that you can halve the RPMs.

Also, pumps have an impeller which is matched to the horse power of the motor. So when replacing the motor, you need to match the braking HP of the old motor with the braking HP of the new motor as close as possible otherwise you either overdrive or underdrive the motor. Underdriving the motor will waste electricity and overdriving may damage the motor.

So if you can get the part number for the 1 HP Northstar two speed motor and impeller, you could replace both and have basically the same pump. The impeller may be the same as the one speed model but I would check that.

[njpool]

I'm looking to replace my Hayward Superpump motor, since it seems that the bearings are shot & it's noisy as heck. I am considering the option of upgrading to a 2 speed motor.

Current Specs:
Part: SP1610Z1M
HP: 1.5
Frame: 56J
Service Factor: 1.0
KW: 1.10
Volts: 115/230
RPM: 3450

I'm looking at AO Smith replacement motors, but I'm getting confused with all the data. It seems most of these motors are switchless, so do I need to buy a hi-lo switch or is it really part of the motor? How do I know I am running at 115 or 230 volts? One of the AO Smith motors I am considering is a 2 spd, 1.5/.20 hp motor that runs at 3600/1800 rpm. Does the difference in RPM matter?

I'm getting so confused as to go back to a single-speed