Is the starting capacitance of a single-phase motor the same as the operating capacitance?
Starting capacitance is to make the starting coil of single-phase motor power on when starting and cut off after starting,
The running capacitance is to make the motor compensate for the capacitance in operation, so the starting capacitance cannot be less, and the running capacitance can not be used.
No matter what kind of capacitor, it has the function of starting at the beginning of single-phase motor starting. However, when the motor reaches about 75% of the rated speed, the starting capacitance is automatically disconnected by the centrifugal switch, while the operating capacitance accompanies the motor to continue to work.

The starting process of single-phase motor is actually the process of "phase alignment". Because the single-phase motor is different from the three-phase motor, there is no phase difference and no rotating magnetic field. The function of the capacitor is to make the starting winding current of the motor advance 90 electrical angles of the running winding in time and space, forming the phase difference. Among them, the operating capacitance also plays a role in balancing the current between the main and secondary windings. The starting capacitor works in a short time, and the withstand voltage is required to be above 250V, while the operating capacitor works for a long time, and the withstand voltage is required to be above 400V.
For general motors, its capacitance is adjustable, generally only a few UF. For asynchronous motor, the capacitance is running, mostly under 20uf. Of course, there are also large ones, which mainly depends on the power of the motor. It is estimated that the current of the motor is too large, the winding is overheated and the short circuit is burnt, which is not the problem of capacitance. The short circuit breakdown of the capacitor rarely sees smoke, but sometimes it can smell a special stink.

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