Overhead Crane Electrical Components

The overhead crane electrical components consists of the main hoist circuit, the pay hoist circuit, the trolley circuit, and the large crane circuit.

Crane power supply

Three-phase four-wire AC, AC380V, 50HZ. the whole machine can be conducted by safety slip wire. 

Crane operation methods

The following methods are available for the operation, control and operation of each crane mechanism:

1.Ground operation mode: the crane is operated through the buttons on the ground hand door.

2.Ground remote control operation method: the crane is operated by the remote control transmitter (rocker type) on the ground and the receiving device installed on the control cabinet.

Crane control principle

The crane control principle adopts the following control principle:

1. Lifting mechanism: Adopt the direct starting method of two-speed motor contactor. 

2. Running mechanism: Adopt frequency conversion speed control method.

Crane control circuit

The electrical circuit of the crane consists of the control circuit and the main circuit.

Connected to the control circuit are:

1. device in the driver’s cab platform (if any) door safety switch, only when the door switch is all on, to prepare for crane work.

2. large and small car cross limit travel switch: when the size of the car running to the track near the end, the size of the car running speed is reduced, when the end position of both ends is reached, the corresponding size of the car travel cross limit switch normally closed contacts immediately open, so that the size of the car to stop this direction of operation can only run in the opposite direction, thus playing a protective role.

3. inverter used to protect the motor overload, overcurrent, when the motor current exceeds the inverter’s calibration value, the inverter output action, stop running and alarm and report a fault, only when the fault is lifted can work again.

4. Emergency switch is only for disconnecting the main power supply when the driver encounters an emergency.

5. Stop button for normal stopping.

6. Door switch (if any) is connected to the main contactor circuit for interlock protection, when any one of them is opened, the main contactor is disconnected.

7. Overload contact of the overload limiter is connected to the total contactor circuit for protection when the lift is overloaded.

8. The lifting height limiter is used for the limit protection when the hook reaches the upper and lower limits.