What is service factor of induction motor?

Motor Service Factor (SF) is the percentage of overloading the motor can handle for short periods when operating normally within the correct voltage tolerances. … This means that a 10-hp motor with a 1.15 SF could provide 11.5 hp when required for short-term use.

How do you calculate the service factor of a motor?

Multiply your motor horsepower by the service factor. For example, if you have a 1HP motor and your service factor is 1.25, then you can operate safely at an HP = 1.25HP without overheating or damaging the motor.

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.

What is the service factor of a gearbox?

In simple terms, the service factor is the ratio of the gearbox rated horsepower (or torque) to the application’s required horsepower (or torque). Service factors are defined by the American Gear Manufacturers Association (AGMA), based on the type of gearbox, the expected service duty, and the type of application.

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What is the SFA rating on a motor?

Service Factor Amps

How do I calculate RPM?

To calculate RPM for an AC induction motor, you multiply the frequency in Hertz (Hz) by 60 — for the number of seconds in a minute — by two for the negative and positive pulses in a cycle. You then divide by the number of poles the motor has: (Hz x 60 x 2) / number of poles = no-load RPM.

What is service factor of motor?

Motor Service Factor (SF) is the percentage of overloading the motor can handle for short periods when operating normally within the correct voltage tolerances. … This means that a 10-hp motor with a 1.15 SF could provide 11.5 hp when required for short-term use.

Is a higher service factor better?

A motor operating continuously at any service factor greater than 1 will have a reduced life expectancy compared to operating at rated nameplate horsepower. Insulation life and bearing life are reduced by the service factor load.” … The motor will also last much longer than one continuously in SF.

What is overload factor?

The overload factor Ko makes allowance for the externally applied loads which are in excess of the nominal tangential load, Wt. Overload factors can only be established after considerable field experience is gained in a particular application.

What is NEMA standard for motors?

NEMA is the North American standard for electric motors. NEMA is the publisher of NEMA MG 1-2014, a book that defines the manufacturing standards for alternating-current (AC) and direct-current (DC) motors in North America. The IEC is the standard for electric motors for the rest of the world.

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What is the ratio of gearbox?

A gear ratio is the ratio of the number of rotations of a driver gear to the number of rotations of a driven gear. A colon is often used to show a gear ratio: gear ratio = rotations of a driver gear : rotations of a driven gear. For every rotation of the 45-tooth gear, the 15-tooth gear must rotate 3 times.

What is a 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 do I choose a gearbox?

Basics of Gearbox Selection

  1. Service Factor. Before sizing an application, the customer should determine the service factor. …
  2. Ambient Temperature and Environment. …
  3. Shock Load or Type of Load. …
  4. Output Style or Mechanism. …
  5. Output Shaft or Hollow Bore Size. …
  6. Housing Styles.

What is LRA?

LRA – Locked Rotor Amps: The current you can expect under starting conditions when you apply full voltage. It occurs instantly during start up. RLA – Rated Load Amps: The maximum current a compressor should draw under any operating conditions.

What are locked rotor amps?

The very high current or amperage a motor draws when power is first applied, due to low counter emf. It is usually five to six times the running load amperage.

What does FR mean on a motor nameplate?

Frame Designation

Motors