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Motors and Drives Fundamentals

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Full-Load-Amperage (FLA)

 

Full-Load-Amperage (FLA) refers to the motor's rated-current at rated-load and rated-voltage. This is the amount of current (amps) the motor will draw from the electrical system when producing its rated output horsepower

This value can also sometimes be referred to as: Running Amps, Rated Amps, or just AMPS.

Motors with Dual Voltage Ratings for use at two separate voltages will have dual FLA Values listed corresponding to each operating voltage. In the example nameplate shown, the AMP rating is given as 122/61, and the voltage is listed as 230/460 volts. If the motor was fully loaded and producing its rated output power of 50 horsepower, it should draw:

122 amps at 230 volts
61 amps at 460 volts

When operating at rated-speed and rated voltage, the motor produces rated-output-horsepower. For motors with a service factor of 1.0, drawing substantially more current than its rated-full-load-amperage indicates an overload situation. This will generally cause damage to the stator winding(s) due to the excessive heat produced.

Motor Myth

A popular myth regarding motors is that: operating a motor at the higher of its dual voltage ratings saves money on your electric bill, because it uses less amps.

In reality, you pay for power (watts or kilowatts), and power is the combination of volts and amps that will be the same value for each of the rated values.

 
Example

122 amps X 230 volts = 28,060 watts

61 amps X 460 volts = 28,060 watts

Connecting the motor at the higher rated voltage however will generally allow smaller size (diameter) electrical wires to be run to the motor which can save money on the installation costs.