# How do you calculate multiple motors?

Contents

## How do you calculate multiple motor loads?

To do this, multiply the motor’s nameplate amperage by the supply voltage. If you don’t have nameplate data, then multiply the supply voltage by the current rating shown in the appropriate table in 430, Part N. Use the tables appropriate to your power supply.

## How is motor Fla calculated?

The motor FLA calculator uses the following formulas:

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)

## For what ampacity must you size the feeder conductor if it supplies the following two motors the terminals are rated for 75 C?

Per Table 310.16, a 6 AWG conductor rated at 75°C provides 65A of ampacity, so it’s too small. However, a 4 AWG conductor provides 85A of ampacity, which will accommodate the necessary 78A. Therefore, you need to size this feeder conductor at 4 AWG.

## How do you calculate the power of a 3 phase motor?

Calculate three-phase motor power consumption by multiplying amps by volts by the square root of three (W = AV(sqrt 3). For example, if the motor is drawing 30 amps at 250 volts, you have 30 x 250 x sqrt 3 (about 1.73) = 12,975 watts).

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## How do you calculate motor kw?

Multiply the motor voltage by the full-load current. The result is in watts. Divide watts by 1,000 to give kilowatts. For example, 230 volts x 20 amps = 4,600 watts; 4,600 watts divided by 1000 = 4.6 kilowatts.

## How does MCA calculate Fla?

MCA = 1.25 x [Motor Rated Current + Heater Current]

The “Motor Rated Current” is sometimes referred to as the FLA (full load amps) of the unit.

## How is motor current rating calculated?

“Now the formula,which you know, KWH = Line Current * Line Voltage * Power factor can be applied. The only unknown value ‘current’ can be calculated.” You must not use de time, as P= dW/dt, the correct is kW = Line Current * 1,73*Line Voltage * Power factor * efficiency.