Water pump automatic mutual switching circuit

It allows two water
pumps to be put into operation alternately.
Both manual and automatic control can be realized through the transfer switch SA .
    When the pool is at a low water level, the lower limit signal contact
is closed, relay KAz is closed, KMi is closed, and
pump No. 1 is running. When the pool is at a high water level, the upper limit signal
contact is closed, KAl is drawn in, KMi is released, and the 1-
call pump is shut down. When the pool is at low water level again,
A2, KA3, KA4 are closed, KM2 is closed, and 2
pumps are running. This cycle repeats to achieve the effect of automatic alternation.