Directly started motor automatic mutual switching circuit a

(1) Directly started motor automatic mutual switching
    circuit The circuit is shown in Figure 3-65. The two water pumps serve as backup for each other. When the working pump fails or its thermal relay is activated, the backup
pump will automatically put into operation. This circuit can also be operated manually. Water level control can use reed switches or electric contact pressure gauges.
    This line can be used for automatic water supply and automatic drainage of high-level water tanks. When used for automatic water filling in high water tanks,
the pump will stop at high water levels and start at low water levels.
    In the figure, when the water level in the water tank rises to the high water level (upper limit), the buoy magnetic ring draws the normally closed contact of the reed switch KR
open, the relay KAI is released, the contactor KM] is released, and the water pump stops running. When the water level in the water tank drops to the lower limit, the water pump
starts filling again. Repeat the above process to keep the water level in the water tank within a certain range.