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What is the duty factor of an electric motor used in residential?

I have heard of the word Service Factor (SF) For example, the standard SF for open drip-proof (ODP) motors is 1.15. This means that a 10-hp motor with a 1.15 SF could provide 11.5 hp when required for short-term use. Some fractional horsepower motors have higher service factors, such as 1.25, 1.35, and even 1.50. The National Electrical Manufacturers Association ( US NEMA) defines service factor as a multiplier, when applied to the rated horsepower, indicates a permissible horsepower loading, which may be carried under the conditions specified for the service factor at rated voltage and frequency. HVAC motors are very often Open Air Over applications where the motor drives a fan, and the airstream of the fan cools the motor en motor windings. HVAC fan motors are under a pretty constant load of the resistance in the air duct system and the air filter in it. If the filter is regularly replaced and the ducts are designed right for the fan output, there is no need for a large fudge (Service Factor) in the motor output.

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