“True HP” of pump

[Neemer]

I need a little help understanding this. I’ve been engaged with an online supplier about a replacement motor for my Hayward Super Pump. They informed me that the true hp of my existing 1.5hp pump is 2.2hp, and I need a bigger motor than the one I was looking at. They have directed me to one with 2.7 hp. Can someone explain how they arrived at the 2.2 figure?

 

[ajw22]

That looks like a 1.5 HP motor with a Service Factor SF of 0 which outputs 1.5 brake HP.

My guess is that store does not have a 1.5 HP motor to sell you and trying to steer you to what they have. Shop elsewhere.

Understanding pump "Service Factor"

What exactly is "service factor"? I was looking around, and found this page- http://www.electricmotorwarehouse.com/pool_pumps.htm Comparing the standard pumps to the high efficiency pumps, the high efficiency have higher service factors. But they seem to use more amps, which is confusing me...

www.troublefreepool.com

 

[JamesW]

You really don't need that much pump. You would probably be ok with a smaller impeller sp2607c and a total 1.0 hp motor.

 

[Neemer]

Thanks. If it makes any difference, and I don’t think it does, I’m planning to replace what I have with a VSP. It appears what I was looking at originally was correct.

 

[ajw22]

If you are shopping for a VS motor then it is a different conversation.

A VS motor is a variable HP motor. However running a larger HP VS motor at slower RPM and lower HP is more energy efficient. So a 2.7 HP VS motor that you run at less then 1 HP may be best for you. It would use less electricity then a 1.5 HP VS motor running at less then 1 HP.

 

[Neemer]

Learn something every day. Thanks so much!

 

[JamesW]

A larger VS pump should be roughly the same efficiency as a smaller VS pump at the same flow rate.

If you're going to replace the motor, you just need a total hp of 1.5 or higher.

It might make more sense to replace the whole pump instead of the motor.

Compare the total cost and labor.

Variable speed pumps sometimes have rebates available from the manufacturer and/or your utility.

 

[cfherrman]

Electric motors only use what the demand is, so if you have a 50 hp motor and are only using 1 hp, you only burn 1 hp of energy.