Where's a good online place to buy a pump/motor?

[Jimmy C]

Coolguy,

I just replaced my motor with an equivelant HP 2 speed motor. I'm beginning to think I should have went down to 1.5 HP for my application, but now that I did it I will make the best of it. I purchased a relay, and a switch to deal with the speed selection. Now I need to make a time delay circuit so that the pump comes on at HIGH speed from anywhere between 3 minutes to 1 hour, and then switches to low speed for the rest of the pump ON time. Time delay relays are usually large, and expensive, so I plan on making my own timer circuit. The idea is to hide all this inside my Intermatic 1102 timer (the one with freeze protection).

Playing with motor speed with a single speed motor is possible, not recommended, and pretty complicated. This is often done with commercial 3 phase motors that employ variable speed by changing the voltage, and frequency simultaniously, i.e. lower speed means lower voltage, and lower rotating field frequency. I have actually done this with a single phase induction motor, but doing so took a lot of equipment, and it was only to prove the concept. Starting the motor is tricky too. For us pool folk, pick a motor designed for two speeds, and go for a swim!

Does anybody out there know or have data relating power factor of 2 speed motors for both LOW and HIGH speed?

Jimmy

[Brock]

Just keep in mind if you change out just the motor it will use the same HP no matter what is connected (given the same RPM). Say a 2hp pump and motor assembly is connected. You pull the 2 HP motor and put a 1HP motor. It will try to do the exact same work the 2HP was doing since the pump is the same, and should take approximately the same power. The way two speed motors get around this is speed. A single speed is typically the same at 1/8 HP to 2 HP.

[Jimmy C]

Brock, You make a lot of sense. My pump is pretty old, like 22 years old, and when I bought the house here in 2004, there was a 2 HP 1 speed motor on the pump. I have had two different folk tell me that my pump was supposed to have a 1.5 HP motor, not a 2 HP. I guess I forgot about that when I upgraded to a 2 speed pump. So I guess this means that my motor would be lightly loaded on high speed, and this would likely decrease the power factor. Then again maybe the impeller was also changed to match the motor. Who knows. I guess I'll take a amp-clamp to see if the motor draws rated amperage on high speed. I guess if the power factor is low, the current draw will remain high even if the motor is lightly loaded. I got some motor starting capacitors around to see if the they can decrease the current draw when placed across the motor wires. If that happens, maybe I can correct for low power factor. Do you or anyone out there ever get into this power factor correction stuff with pool puimps?

[Brock]

Honestly I don't think you will be to far off power factor wise. I am sure it will have a decent load running in high. I never thought to check the power factor running in low on mine, but never had an issue.