View Full Version : Full-load current for single-phase AC motor
test11
April 9, 2020, 07:08 PM
The full-load current for a single-phase alternating current 115 volt, 1 horsepower motor is which of the following:
Gonna need motor efficiency and power factor to calculate the answer.
SecondGen
June 17, 2020, 11:45 AM
The full-load current for a single-phase alternating current 115 volt, 1 horsepower motor is which of the following:
Gonna need motor efficiency and power factor to calculate the answer.
Answer comes from NFPA 70 Table 430.248: 16A at 115V for single phase 1HP motors. I'm not sure how they calculate this without the values you mentioned. Maybe they use a standard efficiency and PF constant?
1HP motors have a typical PF of 0.84 based on this: https://www.engineeringtoolbox.com/power-factor-electrical-motor-d_654.html
Using that info and an Efficiency of 50% gets you close using this calculator: https://goodcalculators.com/motor-fla-calculator/
Anyone know how NFPA gets these values?
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