The Use And Maintenance Of Electric Hoist

The Use and Maintenance of Electric Hoist
 

The electric hoist is composed of a motor, a transmission mechanism and a reel or sprocket, and is divided into two types: wire rope electric hoist and chain electric hoist.
 

It is usually driven by a squirrel-cage conical rotor motor with its own brake (or a cylindrical rotor motor equipped with an electromagnetic brake). The lifting capacity is generally 0.1-80 tons, and the lifting height is 3-30 meters.
 

Most electric hoists are operated by people on the ground with buttons, and can also be operated in the cab or wired (wireless) remote control. In addition to being used alone, the electric hoist can also be assembled with manual, chain or electric trolleys and hung on the roof of the building or the beam of the crane.
 

Both chain hoists and lever hoists are called manual hoists, which use human power to lift heavy objects.
 

Electric hoist is a light and small lifting equipment with a wide range of uses. It is characterized by small size, light weight, and large carrying capacity. It is often installed on electric single-girder bridge gate cranes and suspension cranes to lift and move items.
 

There are many types of electric hoists Electric hoists mainly include wire rope electric hoists, chain electric hoists, miniature electric hoists and explosion-proof electric hoists.

 

 

Maintenance
 

1. For electric hoists that are newly installed or installed after dismantling and inspection, they should first be tested with an empty car for several times. But before the installation is completed, it is forbidden to turn on the power for trial run.
 

2. Before normal use, a static load test should be carried out at 125% of the rated load, lifted about 100 mm from the ground, for 10 minutes, and checked whether it is normal.
 

3. The dynamic load test is based on the rated load weight, repeated lifting and left and right movement tests, after the test, check whether the mechanical transmission part, electrical part and connection part are normal and reliable.
 

4. In use, it is absolutely forbidden to use it in an environment that is not allowed, and when it exceeds the rated load and the rated closing times (120 times) per hour.
 

5. During installation, commissioning and maintenance, it is necessary to strictly check whether the limit device is flexible and reliable. When the hook is raised to the upper limit position, the distance between the hook shell and the reel shell must be greater than 50mm (10t, 16t, 20t must be greater than 120mm). When the hook is lowered to the lower limit position, the safety ring of the wire rope on the reel should be ensured, and the effective safety ring must be more than 2 turns.
 

6. It is not allowed to press two flashlight door buttons that make the electric hoist move in opposite directions at the same time.
 

7. After the work is completed, the main switch of the power supply must be opened to cut off the power supply.
 

8. The electric hoist should be operated by a special person, and the operator should fully grasp the safety operating procedures, and it is strictly forbidden to pull and hang it crookedly.
 

 

9. The electric hoist must be inspected regularly by specialized personnel during use, and timely measures are taken when faults are found, and carefully recorded.
 

10. When adjusting the braking slide of the electric hoist, it should be ensured that under the rated load, the braking slide is S≤V/100 (V is the stable lifting distance of the load within one minute).
 

11. Scrapping standards for wire ropes:
The inspection and scrapping standards of steel wire ropes shall be implemented in accordance with CB/T5972-1986 "Practical Specifications for Inspection and Scrapping of Steel Wire Ropes for Hoisting Machinery".
 

12. The electric hoist must maintain enough lubricating oil during use, and keep the lubricating oil clean, and it should not contain impurities and dirt.
 

13. When oiling the steel wire rope, use a hard brush or a small wooden piece. It is strictly forbidden to directly oil the working steel wire rope by hand.
 

14. When the electric hoist is not working, it is not allowed to hang heavy objects in the air to prevent permanent deformation of the parts.
 

15. During use, if a fault is found, the main power supply should be cut off immediately.
 

16. Special attention should be paid to the wearing parts during use.
 

17. After a long period of continuous operation, the 10-20 ton hoist may automatically cut off the power. This is the overheating protection function of the motor. At this time, it can be lowered. After a period of time, the motor can continue to work after it cools down.

 

Safety Precautions
 

On the basis of understanding the operating instructions, please also pay attention to the following items:
 

1. Please read the instruction manual and the contents on the nameplate before operating.
 

2. Please adjust the upper and lower limit stop blocks before lifting the object.
 

3. Before using the electric hoist, please confirm whether the brake condition is reliable.
 

4. If the following abnormal conditions are found on the wire rope before use, never operate it.
 

(1) Bending, deformation, corrosion, etc.
 

(2) The degree of fracture of the wire rope exceeds the specified requirements, and the amount of wear is large.
 

5. Please use a 500V megger to check the insulation resistance of the motor and control box before installation and use. The cold resistance at room temperature should be greater than 5MΩ before use.
 

6. Please never lift objects exceeding the rated load, the rated load is marked on the nameplate of the lifting hook.
 

7. It is forbidden to take people on the lifting object, and never use the electric hoist as the lifting mechanism of the elevator to carry people.
 

8. No one is under the lifting object.

 

 

9. Lifting objects and hooks cannot be lifted in a swinging state.
 

10. Please move the hoist to the top of the object before lifting, and do not hang it obliquely.
 

11. The limiter is not allowed to be used repeatedly as a travel switch.
 

12. Do not lift objects connected to the ground.
 

13. Please do not over-jog to operate the explosion-proof electric hoist.
 

14. Do not pull other objects forward with the flashlight door wire.
 

15. Be sure to cut off the power before maintenance inspection.
 

16. Maintenance and inspection work must be carried out under no-load condition.
 

17. Please confirm whether the wedge is installed firmly and reliably before use