# Dingfeng Capacitor-- Single-phase motor capacitor size matching

Generally, the capacitance of a single-phase motor is designed according to the power of the motor. For example, a 1 kW dual value motor starting capacitor is between 100 and 200 uf, and the running capacitor is about 30 uf.

How to calculate the starting capacitor and running capacitor of single-phase motor?

Running capacitor capacity:C=120000*I/2.4*f*U*cosφ

I is the current; f is the frequency; U is the voltage; cosφ is the power factor of 0.5~0.7.

The starting capacitor capacity is (1.5~2.5)times the running capacitor capacity.

The working capacitance is 1-4 uf per 100W. The startup capacitor is 4-10 times the working capacitor. If your motor does not exceed 200W, the starting capacitor will not exceed 100uf. The running capacitor can be selected with several values for the power-on test to see which capacitor has the smallest current. The capacity of this capacitor is the best value.

When replacing the starting and running capacitors, it is best to use the same capacitor as the original configuration parameters.

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