Simple and easy-to-make bridge crane control circuit

The new controller of the bridge crane is composed of three-phase AC solid-state relay (SSR) and inching control button. The control system circuit is simple, easy to make, safe and reliable to use. There is no noise during operation, which is better than using contactors.

The working principle of the circuit is shown in the attached figure. When working, close the power supply automatic ZD and the power supply single-pole switch SW. When the button SB1 is pressed, the attraction coil of the AC contactor C is energized and self-locked. Its three pairs of normally open main contacts C are closed and connected to power the six solid-state relays (SSR1~SSR6). When the bridge crane needs to move eastward, press the control button SB3. The AC input control end of the solid-state relay SSRI is turned on by the AC220V power supply, so that its AC output controlled end is turned on. The trolley travel motor M1 starts to run, driving the gear transmission to drag the trolley eastward. When the trolley reaches the working position, release the button SB3. The input control circuit of the solid-state relay SSR1 is de-energized, the solid-state relay SSR1 is turned off, the motor M1 stops running, and the trolley stops moving forward. If you need to start the trolley southward. Press the button SB5. The AC220V input control end of the solid-state relay SSR3 is turned on, so that its AC output controlled end AC380V is turned on. Motor M2 starts to run. Drag the transmission gearbox to drive the trolley to move southward. When it reaches the working position, release the button S85. The solid-state relay SSR3 loses the control power supply and is cut off, the motor M2 stops running, and the trolley stops moving.

When the button SB7 is pressed, the solid-state relay SSR5 is turned on. The motor M3 is powered on and the hook is dragged down. When it is lowered to the working position, the button SB7 is released. The solid-state relay SSR5 is powered off and M3 stops running, and the hook stops descending. When the hook is equipped with a heavy object to be lifted, the button SB8 is pressed, the solid-state relay SSR6 is turned on, and the motor M3 runs in the opposite direction due to the three-phase AC380V power supply after the B phase and the C phase are switched. The hook is dragged upward and runs in place, and the button SB8 is released. The solid-state relay SSR6 is powered off and the motor M3 stops running.

The new type of bridge crane controller introduced in this article is used to control the operation of the bridge crane. The longitudinal and transverse directions of the crane and the lifting of objects can be arbitrarily controlled, and the use is very flexible.

Electrical components selection

The control buttons SB1, SB2, SB8 use a portable 8-button hanging button box, which is connected to the crane with a 10-core rubber-sheathed soft cable. The solid-state relays SSR1, SSR2, and SSR6 use 3AE series solid-state relays. The AC input is rated at 50V~220V/AC. The rated input current is ImA~lOmA/Ac. When selecting, the current margin of the solid-state relay should be increased. A heat sink should be installed. A varistor RY820V is connected in parallel to the output end of the solid-state relay to protect the SSR. Compared with the (electromagnetic relay MER), the solid-state relay (SSR) has the characteristics of low noise, high sensitivity, durability, and high operating frequency. It can replace the electromagnetic relay. It is used to drive electromagnets, solenoid valves, incandescent lamps, single-phase and three-phase motors, etc.