3 Horsepower Motor Reviews

In most cases, this is a sales ploy and not the true (HP) Horsepower rating of the motor. It is what is called the break horsepower. What does this mean? It means that when the motor first starts up, if it could run continuously at that horsepower, it would be the horsepower rated on the tag. However, no motor runs continuously at that rate.

So how do we figure out the actual horsepower rating of the motor we have on our pool or spa pump?

First of all you have to remember that the horsepower rating is the amount of work that motor will do on a continuos basis. Whether running 24 hours a day on a pool or for 2 hours at a time on a spa. The actual horsepower is all the motor can do without being over loaded.

- First look for the spec tag on the motor itself, Usually a large tag with lots of information.
- Find the voltage of the motor. Typically 110 volts or 220 volts.
- Next find the amp rating of the motor. This can be any number and is the key in finding horsepower.
- Once you have the proper voltage and the amp rating in hand. Multiply the amps times the volts. i.e.; 220 volts time 8.5 amps = 1870
- Now divide 1870 (or whatever number you came up with) by 1024 (1 electrical horsepower unit). In our case above you will get 1.826 this is the horsepower of the motor, it is just over a 1.5HP motor.
- Now to find the actual horsepower (or work load) the pump motor can do, multiply the 1.826 by.75.

This takes into account that the motor will be running under a load and not just freewheeling through out its life.

In our case above the horsepower rating is 1.826 multipied by.75 equals 1.3. Well that is odd because you never see a 1.3 hp pump motor on a spa or pool right? So whats the deal?

There is one more number that is needed to accomplish a true horsepower rating on the motor. It's the S.F. number (the Service Factor number) on the spec tag. Once you have figured out the motor horsepower rating (in our example above 1.3 HP) you must then multiply that number times the S.F. number. S.F numbers are typically 1.0 to 1.65. The S.F. (Service factor) Number is the manufacturer way of telling you exactly how much work that particular motor will do.

So in our case of the motor we had tagged at 4HP and figured out to be actually 1.3HP once multiplied times the 1.65 S.F. (service factor) we get 2.145 HP for the amount of work that motor will do under load. So, we can safely install a 1.5 HP impeller for what is called a Full Rate motor or a 2.0 HP impeller for what is called an up rated motor.

A 1.5HP motor (full rate - 1.65 S.F) can be used as a 2.0HP and is the same motor as a 2.0HP (up rate - 1.0 S.F)

I hope this has cleared some of this up for you. Spa manufacturers and pump manufacturers like to make you think you are getting more HP (horsepower) with their spa or pump rather than with the competitor's spa or pump. When in all actuality they are exactly the same.