Circuit for increasing the starting torque of a single-phase capacitor-operated motor

The starting torque of a single-phase capacitor-operated asynchronous motor is usually very small, only 20% to 30% of the rated torque, so
it can only be started without load or with a very light load. In order to improve the starting torque of this type of motor , the circuit
shown in Figure 3-15 can be used . That is, the device in the dotted box in the figure is connected to the motor circuit . Connecting capacitor C2 during startup can increase the starting torque of the motor to 2 to 4 times the rated torque. After starting, relay KA is released.     Resistor R can be selected according to the formula:     R≈installation (n) where Ide - rated current of the motor , A;     U. ——Rated voltage of sensitive relay KA, V.