Delayed Automatic Forward Reverse Motion of Overhead Crane Driven by a Motor

This is another situation that requires the overhead crane to rest for a while 

upon reaching both of the rail. After a pre-determine time the overhead crane 

will re-start in the opposite direction.

Control circuit of "Delay Automatic Forward Reverse Motor of an Overhead Crane"

The control circuit of this system is shown Above. Two times TR1 and TR2 are connected to the limit switches Y and X respectively at terminal 3.

The terminal no. 1 of the instantaneous contacts TR1(1-3) and TR2(1-3) are connected to the terminals no. 3 of the limit switch Y and X respectively. The delay contact TR1(6-8) and TR2(6-8) are connected to the contacts R(13-14) and F(13-14) respectively.

Supposing the overhead crane is moving in the forward (right) direction that means, contactor F(A-B) is at energized and contactor R(A-b) is at de-energize condition. When the overhead crane reaches the right end limit and touches the limit switch Y, the contact Y(1-2) of limit switch Y will open to de-energize contactor F(A-B). This will bring the overhead crane to stop moving in the forward right direction and it will remain at stand still for a pre-determine time set by timer TR1. Also the contact Y(1-3) of the Y limit switch will close to de-energize timer TR1. The instantaneous contact TR1(1-3) will close instantly to maintain TR1 continously energized.   

After the pre-determine time set by TR1, the delay contact TR1(6-8) will close to energized contactor R(A-B). This will cause the overhead to start moving in the reverse (left) direction. At this point the connection of limit switch Y contacts Y(1-2) will open and contact Y(1-3) will close.

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When the overhead crane reaches the left and it touches the limit switch X, the contact X(1-2) of limit switch X will open to de-energized contactor R and timer TR1. Instantaneous contact TR1(1-3) will open. At this point the overhead crane will stop moving in the reverse (left) direction and it will remain at stand still for pre-determine time set by timer TR2. Also the contact X(1-3) of the X limit will close to energized timer TR2. The instantaneous contact TR2(1-3) will close instantly to maintain TR2 continuosly energized. After the pre-determine time set by timer TR2, the delay contact TR2(6-8) will close to energize contactor F(A-B). 

When the contactor F(A-B) is energized, it will cause the overhead crane to start moving in the forward (right) direction. Immediately after, the connection of contact X(1-3) will open and contact X(1-2) will close again. Timer TR2 will remain energize because its instantaneous contact TR2(1-3) is maintain close. Timer TR2 will be de-energized when the overhead crane reach the right end limit and touches limit switch Y.