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

[joelq]

I have 6 month old Northstar 1-speed pump that I'm considering upgrading to a 2-speed. I've noticed prices of the Northstar 2-speed pumps to be in the $600 range, whereas replacement motors are only in the $200-$300 range.

Is it a viable option to just replace the motor when upgrading to a 2-speed pump? I'm assuming the pump itself is identical between 1 and 2-speed models? I'm hoping to not only save money, but also avoid having to redo the pump plumbing.

I'd be hooking the new motor to my Aqua Logic PS-8, which should already support the 2-speed pumps.

Thanks!

[waste]

Joe, to to the best of my knowledge, the motor is the difference between 1 and 2 speed pumps (it would be ludicrist to have to change the impeller when changing speeds;) ) There are others here who know the 'ins and outs' of motors better than I, if I've given the wrong answer, one of them will step in and correct me.

[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