Replacing pump motor

[bbsmith]

Thanks for all the input.

But after reading thru everything I am a little confused?

Which type of motor is more energy efficient (uses less KW or Amps to run a pool, Cost less)
VFD or ectro-mechanical hi-E 2-speed?

And does the ImPower have the same efficent as a VFD? The specs say that the ImPower has max 1.25 Output (1 HP up-rate) and 3 speeds (3450, 2600, 1725)

[PoolDoc]

ImPower appears to be a VFD with preset, rather than variable, speeds. It also has a pretty inflexible -- and unchangeable -- control program.

Mark (mas985) has looked at motor efficiency more than I. But from what I can tell:
+ companies (including AOSmith) haven't published motor efficiency figures for fractional (under 5HP) motors.
+ the California data, which shows OVERALL efficiency of pumps, in some cases compares identical wet ends mated with either dual speed or VFD motors. This data contains some obvious errors. BUT, it looks like the VFD motors may be a little more efficient. However, the difference probably will NOT be large enough for you to notice on your power bill.

[mas985]

Which type of motor is more energy efficient (uses less KW or Amps to run a pool, Cost less)
VFD or ectro-mechanical hi-E 2-speed?

A VS will always be more efficient and cost less to run but it may not be enough to pay for the extra cost of the pump.

And does the ImPower have the same efficient as a VFD? The specs say that the ImPower has max 1.25 Output (1 HP up-rate) and 3 speeds (3450, 2600, 1725)

The ImPower would probably be more efficient than the same size two speed motor but not as efficient as a true VS. A VS has the ability to optimize the speed for the particular job, where as the IMPower is a fixed three speed, so there is less flexibility.

The cost savings for any of these options will depend on how the pump is used. With solar, you will be using the pumps at high(er) speed most of the time so may see only a small change in your power bill. However, the VS would allow you to set the speed for just enough flow rate to keep the vacuum release closed and minimize energy use.