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## How much more current does a motor draw on startup?

Often, during the initial half-cycle of electrical current flow experienced at motor startup, (Note: A half-cycle in a 60 Hz electrical system equates to 1/120 of a second duration of time) inrush currents reach **levels 20 times greater than the normal current levels** experienced during the motor’s normal operating …

## How do you calculate the starting amps on a motor?

You can **multiply the code (amps) times the Horsepower of motor** to determine starting amps. Find a list of codes and the amps here. Cycles (Hz) – All U.S. electrical appliances run at 60 cycles per second.

## How much current does an across the line motor draw when it starts?

With across-the-line ac starting, the blower-motor system intakes full voltage and draws line amperage that’s often **300% to 600% more than its rated operating current** — or in the case of some high-performance setups, to 800% more than operating current.

## Why is inrush current so high?

High inrush current is **the result of the maximum instantaneous input current drawn by an electrical device during the initial power up**. As technology continues to advance, most systems today run efficiently and maintain a low impedance which in turn contributes to high inrush current.

## Why motor Take heavy current at starting?

At start, **the slip of the motor is equal to unity and the induced rotor voltage is equal to the stator voltage**. The rotor-induced voltage goes on decreasing as the motor accelerates towards its base speed. It is clear that the induced rotor is maximum at the starting of the motor.

## How do you calculate the full load current of a motor?

Full load current I, I **=P**. **/ 1.732 * V Amps**.

## How long does motor inrush current last?

These currents can be as high as 20 times the steady state currents. Even though it only lasts for **about 10ms** it takes between 30 and 40 cycles for the current to stabilize to the normal operating value.

## How is inrush current of a motor calculated?

The range is given in thousands of Volt-Amps, or kilowatts. **Multiply each number in the range by 1,000**. Divide each result by the motor voltage found on the nameplate. The resulting range is the inrush current range.