The full load (rated) current of a motor is in three phases. I_n = P / (√3·U·cosφ·η) ile bulunur. Örneğin 15 kW, 400 V, cosφ 0,85, verim %90 için ≈ 28 A. En doğru değer motor etiketinde (nameplate) yazar.

3F: I_n = P / (√3·U·cosφ·η) · 1F: I_n = P / (U·cosφ·η)
Example calculation: 15 kW, 400 V, cosφ 0,85, verim %90 → I_n = 15000/(√3×400×0,85×0,90) ≈ 28,3 A.

Motor Full Load Current

Calculate the full-load (nominal) current based on motor power, voltage, power factor, and efficiency. The exact value is on the motor label.

Full load current I_n
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Notes: 3F: I_n=P/(√3·U·cosφ·η); 1F: I_n=P/(U·cosφ·η). The exact value is from the engine label. The current (cosφ) and efficiency vary depending on the motor and load. The thermal relay and cable are selected according to this current.
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How is it calculated?

  1. Select the motor power (kW) and system (1F/3F).
  2. Enter the voltage, power factor (cosφ), and efficiency.
  3. Press Calculate.

Frequently Asked Questions

How is motor current calculated?
In 3-phase I_n = P/(√3·U·cosφ·η); power, voltage, power factor and efficiency are used.
How many amps does a 15 kW motor draw?
400 V, cosφ 0,85, verim %90 için yaklaşık 28 A; gerçek değer motora göre değişir.
Why should you check the engine label?
cosφ and efficiency vary depending on the motor and load; the most accurate value is the rated current on the label.

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This tool and its content are for general informational purposes only; they do not constitute a binding inspection/declaration of conformity. Definitive results will be determined through on-site inspection in accordance with relevant legislation and standards. Get a quote →