3 Phase Motor Current Calculation Formula Explained

Today I am sharing with new simple and easy 3 phase motor current calculation formula for LT motors. In this post, I am sharing with you a nameplate of 3 phase low voltage induction motor. In the nameplate, all data are given by the manufacturing companies.

3 phase motor current calculation formula

3 Phase Motor Current Calculation Formula Explained

In the below image I have shown a 3 phase motor nameplate. In the motor nameplate, the company provides the motor is 15 KW 3 phase induction motor. The Eff of the motor is 0.89 and PF is 0.85. The volts of the motor 380V and Amps are 30.1.

So this data is provided by the company. Now first see the image and after that, we start doing the current calculation of 3 phase motor. That how comply calculate the current of three phase motor and how 30.1 amperes are given in nameplate.

3 phase motor nameplate details

For 3 phase low voltage motor current calculation, we need the motor volts, Eff, PF. For three phase motor amps calculation, the below formula is used.

3 phase motor current calculation formula is P/(√3xVxPfxEff) or P/(1.732xVxPfxEff) Both are the same.

So our motor power is 15KW with 15 x 1000 = 15000 Watts. Motor volts are 380 volts, Eff is 0.89 and PF is 0.85 according to the above nameplate.

So if we calculate 15000/(1.732x380x0.85x0.89)

15000/(497.89) So 15000 / 497.89 = 30.12 Amps Or Load current of the motor.

By using this formula you can calculate the 3 phase low voltage motor. This is a very simple and easy formula.

Also, read


I hope this 3 phase motor current calculation formula (how to calculate 3 phase motor current) help you. And know you will be able to calculate the load of 3 phase motor by using the above load current formula. Now if you have any questions or want to give us some suggestions about our blog then you can use the below comment section.

Sikandar Haidar

Electricalonline4u.com is a hub of electrical and electronics tutorials and easy diagrams.


  1. if possible write about formula or any calculation.
    how to find suitable cable for load

  2. please publish how to perform
    short circuit analysis

  3. give us some formulae equation on amps voltage ampere if u have more give us to me pls tks

  4. Be attaching the Circuits with videos please for better understanding.

  5. Thank you sir for your effort teaching us online

  6. Please tell me about calculation of overload setting.

  7. if p= power, pf=power factor, v=voltage, i=current, eff=?

  8. Pls, how can we reverse single phase motor

  9. Thank u sir if u describe about the magnetic contractor overload relay and mccb breaker size calculation for dol and ster delta starter I will be happy

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