Electrical Motor Calculator

Overview

Engineering reference data for Electrical Motor Calculator in electrical engineering.

Key Formulas

Ohm's Law

$V = IR$

Voltage = Current × Resistance.

Power

$P = VI = I^2R = V^2/R$

Electrical power.

Energy

$E = Pt$

Energy = Power × Time.

Variables

Symbol	Description	Unit
$V$	Voltage	V
$I$	Current	A
$R$	Resistance	Ω
$P$	Power	W

Calculation Formulas

Calculate Current (Amps)

$I = \frac{P_{hp} \times 746}{V \times \sqrt{3} \times \text{PF} \times \eta}$

Where:

• $I$ = Current (Amps)
• $P_{hp}$ = Power (horsepower)
• $V$ = Voltage (Volts)
• $\text{PF}$ = Power Factor
• $\eta$ = Efficiency (decimal form)

Calculate Power (Horsepower)

$P_{hp} = \frac{I \times V \times \sqrt{3} \times \text{PF} \times \eta}{746}$

Calculate 3-Phase Apparent Power (kVA)

$S_{kVA} = \frac{P_{hp} \times 746}{1000 \times \eta}$

Key Notes

• RLA (Running Load Amps): The current drawn during the normal operation of an electric motor.
• FLA (Full Load Amps): The current drawn when the motor is operating at its full-load torque and horsepower. FLA is typically determined through laboratory tests.
• Important Relationship: In the context of this calculator, FLA is considered to be RLA + 25%.
• Unit Conversion: 1 horsepower (hp) = 0.745 kilowatts (kW).

References

• Original Source