Frequency sensitive rheostat manual forward and reverse starting circuit

The circuit is shown in Figure 3-166. It uses button control. When starting in the forward direction, press SB], and the motor rotor will run through the frequency-sensitive
rheostat RF. When the motor speed rises to close to the rated speed, press the short-circuit button SB3 and the RF will exit operation.
When starting in the reverse direction, just press SB2. The starting process is the same as the forward starting process .