You asked: What is the service factor of a motor?

The service factor – SF – is a measure of periodically overload capacity at which a motor can operate without damage. The NEMA (National Electrical Manufacturers Association) standard service factor for totally enclosed motors is 1.0.

What is 1.15 service factor?

Motor “service factor” is probably the most misunderstood value on a motor nameplate. To most it seems quite simple; if it is a 1.0 you can run a motor to 100% load, if it is 1.15, then it can be loaded to 115% of its rated load.

How long can a motor run in service factor?

If the theoretical life expectancy of this motor was 10 years, it could be expected to last 1.5 years when operated continuously at the SF load. Although many other factors may also affect motor life, this example illustrates how important temperature considerations are in the proper application of the equipment.

What is NEMA service factor?

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.

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What is the SFA rating on a motor?

Service Factor Amps, or S.F.A., represents the amount of current the motor will draw when running at the full Service Factor. In the example nameplate, the S.F.A. is eight amps at 230 volts. Continually exceeding the S.F.A. shown on the nameplate can shorten motor life.

What is Pump Service factor?

Generally, service factor is the measurement used to determine the peak performance at which a pump motor can operate. The National Electrical Manufacturers Association (NEMA) defines service factor simply as a multiplier that indicates the amount of additional load a motor can handle above its nameplate horsepower.

How is service factor calculated?

Calculate or determine your service factor by choosing the service factor that corresponds to your hp and various RPM levels. For example, according to the table, if you have a 1HP motor and you operate it at 3600 RPM continuously, your service factor is 1.25. … Multiply your motor horsepower by the service factor.

Is service factor the same as safety factor?

Service factors are used to account for higher torque conditions of the equipment to which the coupling is connected. … Safety factors are used in the design of a coupling.

What is the service factor of a gearbox?

What is a service factor exactly? It’s the ratio of horsepower your gear reducer can mechanically handle compared to the horsepower required for your application. Put simply, it is how overdesigned the gearbox is when it comes to handling the application load.

How do you calculate amp service factor on a motor?

For example, the FLA or full load amps of the motor above is 10.8 amps at 115 volts. The service factor or S.F. is 1.5, making the service factor amps 16.2 (rounded down to 16 on the motor tag) at 115v because 10.8 x 1.5 = 16.2.

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What is service factor in belt drive?

The tables for V-belt drives list service factors that generally range from 1.0 to 1.8 depending on the type of driver (ac motor, dc motor, or internal combustion engine), the type of driven machine, and the duty cycle. … Service factors for synchronous belts run a bit higher, ranging from 1.0 to 2.4.

How is Fla calculated?


  1. Single Phase AC Motor FLA (Amperes) = (P [kW] × 1000) / (V × cos ϕ)
  2. Single Phase AC Motor FLA (Amperes) = (P [HP] × 746) / (V × cos ϕ × η)
  3. Three Phase AC Motor FLA (Amperes) = (P [kW] × 1000) / (V × 1.732 × cos ϕ)
  4. Three Phase AC Motor FLA (Amperes) = (P [HP] × 746) / (V × 1.732 × cos ϕ × η)

What does SLA mean on a motor?

Then I found out that in that context, it means “sealed lead acid.”

Why is my motor over amping?

Electrical overload or over-current is caused by an excessive current flow within the motor windings, exceeding the design current which the motor is able to carry efficiently and safely. This can be caused by a low supply voltage, resulting in the motor drawing in more current in an attempt to maintain its torque.

What is full load current?

Definition of ‘full load current’

A full load current is the largest current that a motor or other device is designed to carry under particular conditions. … A full load current is the largest current that a motor or other device is designed to carry under particular conditions.

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