Motor multiple interlocking reversible circuit

Usually the forward and reverse starting circuits adopt double mutual collar protection, namely: button interlock and AC contactor moving contact interlock. This circuit has triple
interlock protection, namely: button interlock, AC contactor movable contact interlock, and power-off delay time relay power-off delay closing movable contact interlock
. This circuit has a very high degree of interlocking and has the function of blue-reinforcement interlocking protection.
As shown in Figure 4-36,
    when starting forward, press the forward start button SE,2. At this time,
the SB2 moving contactor is disconnected and reverses. AC contactor KM; coil circuit
plays the role of mutual feed protection. At the same time, the moving and closing contact of SB2 is closed, and the
coil of AC contactor KM1 and power-off delay time relay KT1
is powered on at the same time. At this time, the main contact of KM1 is closed, and the motor M starts to rotate
forward. KM1 movable breaking contact and KT1 delayed closing movable breaking
contact are both opened, causing the KM2 coil circuit to be disconnected in three places at the same time,
thus playing a reliable role. Interlock protection.
    When reverse rotation is required, press the reverse start button SB3. At this time, the
forward rotation circuit AC contactor KMI coil is de-energized and released, and the motor
M stops forward rotation, but KT1 loses power and its
contact It can be restored to closed. Even if the reverse start button is pressed,
the reverse start cannot be started. The reverse start can only be started after pressing the reverse start button for 2 seconds (the set time can be adjusted arbitrarily), thus truly playing
the role of interlock protection.