Three Phase Motor Amps Formula:
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The three phase motor current calculation determines the electrical current required by a 20 horsepower three phase motor based on voltage, power factor, and efficiency. This is essential for proper electrical system design and motor protection.
The calculator uses the formula:
Where:
Explanation: The formula calculates the current draw by accounting for the motor's power output, electrical characteristics, and efficiency losses.
Details: Accurate current calculation is crucial for proper wire sizing, circuit breaker selection, motor protection, and ensuring electrical system safety and efficiency.
Tips: Enter voltage in volts, power factor as a decimal (e.g., 0.85), and efficiency as a decimal (e.g., 0.92). All values must be positive numbers within their valid ranges.
Q1: Why is the power factor important in this calculation?
A: Power factor represents the phase difference between voltage and current. A lower power factor means the motor draws more current for the same power output.
Q2: What is a typical power factor for three phase motors?
A: Power factor typically ranges from 0.8 to 0.95 for three phase induction motors, depending on motor size, load, and design.
Q3: How does voltage affect motor current?
A: Current is inversely proportional to voltage. Higher voltage systems require less current for the same power output.
Q4: What are typical efficiency values for motors?
A: Motor efficiency typically ranges from 0.85 to 0.95 for standard efficiency motors, and up to 0.97 for premium efficiency models.
Q5: Why is the square root of 3 used in the formula?
A: The square root of 3 (approximately 1.732) is a mathematical constant that relates line-to-line voltage to line-to-neutral voltage in three phase systems.