1. ## watts

When calculating wattage for different motors I would normally use 240 volts however, the motors have a range listed on them of 208-230 volts. Would I use 208, 230 or 240? Not to mention that they sometimes they even have an amperage range listed. I generally use the highest figures listed on the motor in this case 230 for voltage and what ever the highest amp rating is. This way I would think I am comparing apples to apples. If one particular motor brand did run on 208 my cost analysis would be off. Let me know if there are any other considerations.

220

3. ## Re: watts

If they list both a range in volts and a range in amps then usually you can use either the numbers on the left or the numbers on the right, depending on what voltage you actually have. For example a WFE-4 is 208-230 volts and 7.8-7.4 amps. At 208 volts it is 7.8 amps, and at 230 volts it is 7.4 amps.

Keep in mind that this kind of calculation should not be used if you are trying to estimate the normal day to day power usage. Those are intended to be worst case numbers and different manufacturers have different ideas about what "worst case" means.

If you want more realistic power usage numbers you should look at the California pool pump efficiency test results, see this topic for more info.

4. ## Re: watts

Those different numbers mean the motor is capable of running on a range of voltages.

The power coming into your house comes from a transformer. Depending on the power company, location, etc, the voltage may be set at 220, 230, or 240, or something there abouts.

The 208 has to do with one leg off of a 3 phase system found in a lot of comercial applications. Your house is single phase, so dont worry about the 208. To know what the real draw of the motor is, you would need to measure it under load. If you know whats coming into your house, use that number and the associated amp draw to get a watt number thats close.

EDIT: Jason types faster

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