Enter the power (kW), the voltage (volts), the efficiency factor, and the power factor into the calculator to determine the Motor Current. 

Motor Current Formula

The following formula is used to calculate the Motor Current.

Im = 1000 * P / [ SQRT(3) * V * EF *PF ] 
  • Where Im is the Motor Current (amps)
  • P is the power (kW) 
  • V is the voltage (volts) 
  • EF is the efficiency factor 
  • PF is the power factor

To calculate a motor current, multiply the power by 1000, then divide by the product of 1.732, the voltage, efficiency factor, and power factor.

How to Calculate Motor Current?

The following example problems outline how to calculate Motor Current.

Example Problem #1

  1. First, determine the power (kW). In this example, the power (kW) is determined to be 67 .
  2. Next, determine the voltage (volts). For this problem, the voltage (volts) is measured to be 20 .
  3. Next, determine the efficiency factor. In this case, the efficiency factor is found to be 5.
  4. Next, determine the power factor. This is .85.
  5. Finally, calculate the Motor Current using the formula above: 

Im = 1000 * P / [ SQRT(3) * V * EF *PF ] 

Inserting the values from above and solving yields: 

Im = 1000 * 67 / [ SQRT(3) * 20* 5 *.85 ]  = 455.08 (amps)

Example Problem #2

Using the same method as above, determine the variables required by the formula. For this example problem, these are:

power (kW) = 60

voltage (volts) = 4

efficiency factor = 2

power factor = .85

Enter these given values into the calculator or above yields: 

Im = 1000 * P / [ SQRT(3) * V * EF *PF ]  =5094.26 (amps)