Three Phase Motor Amps Formula:
From: | To: |
The three phase motor amps formula calculates the current required by a 10 horsepower three phase motor based on voltage, power factor, and efficiency. This helps in proper electrical system design and circuit protection.
The calculator uses the formula:
Where:
Explanation: The formula converts horsepower to watts, then calculates the current required considering the three-phase power factor and motor efficiency.
Details: Accurate current calculation is essential for proper wire sizing, circuit breaker selection, and ensuring the electrical system can safely handle the motor's starting and running currents.
Tips: Enter voltage in volts, power factor (typically 0.8-0.95), and efficiency (typically 0.8-0.95). All values must be positive and within reasonable ranges.
Q1: Why is 746 used in the formula?
A: 746 watts equals 1 horsepower, so 10 hp = 7460 watts. This conversion is necessary to work with electrical units.
Q2: What is a typical power factor for motors?
A: Power factor typically ranges from 0.8 to 0.95 for three-phase motors, depending on motor design and load conditions.
Q3: How does efficiency affect current calculation?
A: Lower efficiency means more electrical power is required to produce the same mechanical output, resulting in higher current draw.
Q4: Why is √3 used in three-phase calculations?
A: √3 (approximately 1.732) is the mathematical relationship between line and phase quantities in three-phase systems.
Q5: Should this calculation be used for motor protection?
A: While this provides the full-load current, motor starting currents (typically 6-8 times full-load current) must also be considered for proper protection.