Motor Startup Current Calculator

Formula

To calculate the Motor Startup Current (Isu):

\[ Isu = 4 \times \left( \frac{RP}{\sqrt{3} \times V \times PF \times E} \right) \]

Where:

\(Isu\) is the Motor Startup Current (amps)
\(RP\) is the Rated Power (watts)
\(V\) is the Voltage (volts)
\(PF\) is the Power Factor
\(E\) is the Efficiency

What is Motor Startup Current?

The Motor Startup Current is the initial surge of current required to start a motor. It is typically much higher than the current required to keep the motor running. This current is essential for overcoming the inertia of the motor's rotor and the load it is driving.

Example Calculation

Let's assume the following values:

Rated Power (\(RP\)) = 1000 watts
Voltage (\(V\)) = 230 volts
Power Factor (\(PF\)) = 0.8
Efficiency (\(E\)) = 0.9

Using the formula:

\[ Isu = 4 \times \left( \frac{1000}{\sqrt{3} \times 230 \times 0.8 \times 0.9} \right) = 4 \times \left( \frac{1000}{286.659} \right) = 4 \times 3.49 = 13.96 \text{ amps} \]

The Motor Startup Current is 13.96 amps.