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3-Phase Motor Current Formula:
The 3-phase motor current is the amount of electrical current drawn by a three-phase electric motor when operating under load. It's crucial for proper circuit sizing and protection.
The calculator uses the 3-phase current formula:
Where:
Explanation: The formula accounts for the three-phase power relationship and includes power factor and efficiency corrections.
Details: Accurate current calculation is essential for selecting proper wire sizes, circuit breakers, and overload protection devices to ensure safe motor operation.
Tips: Enter power in watts, voltage in volts, power factor (typically 0.8-0.95), and efficiency (typically 0.85-0.95 for most motors). All values must be positive.
Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work.
Q2: How do I find my motor's efficiency?
A: Check motor nameplate or manufacturer specifications. Typical values range from 0.85 to 0.95 for modern motors.
Q3: Should I use line-to-line or line-to-neutral voltage?
A: Use line-to-line voltage for this calculation (the higher voltage value in a 3-phase system).
Q4: What if my motor power is in horsepower?
A: Convert horsepower to watts first (1 HP = 746 watts) before using this calculator.
Q5: Why is the result slightly higher than my motor's nameplate current?
A: Nameplate current includes a service factor, while this calculation gives theoretical full-load current at rated power.