I. Overview

Electric hoist is a widely used in industrial and mining enterprises, warehousing and logistics, building construction and dock and other occasions of light lifting equipment, with a small size, light weight, simple operation, easy to use and other significant features. Common types include wire rope electric hoist and electric chain hoist. In this paper, we focus on the small wire rope electric hoist with a running mechanism of the composition and structure, principle of operation and common troubleshooting methods.

Second, the composition of the equipment

With a small electric hoist with running car is mainly composed of the following parts: lifting motor, running car mechanism, gearbox, reel, electrical control box, fire limiters, rope guide, push rod and the necessary weight limiting device. The equipment is controlled by handle button or remote control, with good manoeuvrability and safety.

Third, the working principle

The operating principle of the electric hoist is relatively simple and clear. The running part of the car along the track to achieve left and right movement, and lifting motor through the gearbox to drive the drum rotation, and then complete the operation of the wire rope to put away, to achieve the lifting and lowering control of the heavy load. The structure is easy to control the positioning, and supports the point control and electrical interlock mechanism.

Fourth, the principle of electrical control

The electric hoist usually adopts the electrical control method of point action and interlock. The control circuit uses 36V AC voltage, which is provided by 380V step-down transformer to ensure safe operation. Conventional electrical wiring contains rising, falling interlock control and emergency stop protection and other functional modules.

V. Common faults and troubleshooting points

1. no 36V voltage in the control circuit: check whether the step-down transformer is damaged or the wiring is loose as a matter of priority. 2. no response from the pushbutton: it should be checked whether the pushbutton is not responding.

2. button does not respond: should be investigated button switch damage or handle cable broken, the actual fault in the handle broken wire is more common.

3. rising contactor does not respond: in addition to the button and wiring, but also need to check whether the weight limiters and rising limit switch is damaged or malfunctioning.

4. contactor action but motor does not rotate: need to check whether the motor brake can be released normally, make sure that the ignition limiters are in good contact.

5. Tapered rotor motor failure: there may be problems such as the rotor is disconnected from the shaft, the brake cannot be released, the rotor shaft is broken or the brake pads are worn.

6. Reel rope guide abnormality: rope guide action failure may trigger wire rope winding, wrong line or fire limit advance action, it is recommended to adjust the wire rope or replace the rope guide.

7. control contactor problems: including burnt coils, auxiliary contact poor contact or three-phase power shortage, etc., need to be detected and repaired one by one.

Sixth, conclusion

Small electric hoist with a running car has a wide range of application value in material handling and equipment installation due to its compact structure, diverse functions, easy maintenance and other advantages. By mastering its structure and principle, combined with systematic troubleshooting process, can effectively improve the reliability and service life of equipment operation.