How Runing On Service Factor Affect Motors

How to Calculate Motor Service Factors

by Dwight Chestnut

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A service gene, or "SF," is a factor representing the capacity at which a motor can operate without overloading or damaging its cadre or components. The reference point is a service cistron of i, which would mean a motor cannot operate over its rated horsepower, or "hp," without overheating. Similarly, for example, a service cistron of i.25 says the motor can operate 25% over its rated hp without harm or overheating.

Pace 1

Determine the horsepower of your motor. If you do not know it, reference the manufacturer's specifications.

Step two

Refer to the National Electrical Manufacturers Clan table, or "NEMA tabular array", for service factors. The table relates service factors to hp and revolutions per minute, or "RPMs" . Calculate or determine your service factor by choosing the service factor that corresponds to your hp and various RPM levels. For instance, according to the table, if you have a 1HP motor and you lot operate it at 3600 RPM continuously, your service factor is 1.25.

Calculate your operating or "effective" HP level. Multiply your motor horsepower past the service factor. For instance, if you have a 1HP motor and your service cistron is ane.25, so you lot can operate safely at an HP = 1.25HP without overheating or damaging the motor.

References

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