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Three Phase Motor Amps Formula:
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The three phase motor amps formula calculates the current drawn by a three phase motor based on its power rating, voltage, power factor, and efficiency. This is essential for proper electrical system design and motor protection.
The calculator uses the three phase motor formula:
Where:
Explanation: The formula converts horsepower to electrical power, then calculates current based on the three-phase power equation, accounting for power factor and efficiency losses.
Details: Accurate current calculation is crucial for proper wire sizing, circuit breaker selection, motor protection device setting, and ensuring electrical system safety and reliability.
Tips: Enter voltage in volts, power factor and efficiency as decimal values between 0 and 1. All values must be positive and within valid ranges for accurate results.
Q1: Why is 746 used in the formula?
A: 746 is the conversion factor from horsepower to watts (1 hp = 746 watts), converting mechanical power to equivalent electrical power.
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, load, and operating conditions.
Q3: What is motor efficiency?
A: Motor efficiency represents the ratio of mechanical power output to electrical power input, typically ranging from 0.85 to 0.95 for modern motors.
Q4: Why is √3 used in three phase calculations?
A: √3 (approximately 1.732) is the mathematical relationship between line voltage and phase voltage in a balanced three-phase system.
Q5: Can this formula be used for motors of different horsepower ratings?
A: While this calculator is specifically for 5 hp motors, the formula can be adapted by replacing the 5 with the desired horsepower rating.