The electric hoist adopts unique design of turbine rod, which consists of motor, main brake and auxiliary brake, reducer, rope wheel and pressure rope mechanism. When working platform rising up and down, the electric hoist does not rewind or release wire rope, the friction between rope wheel and wire rope as the driving force to lift the platform.
The blocking torque of electric hoist should not be lower than 180% of rated torque. It should have a good performance, no stuck or blocked rope. All rotating exposed parts should be protected. The brake must be suspended with a rated load of 125% and stop running with a slip distance of no more than 100m.
It is forbidden to use clutch and friction drive in the lifting system. The ratio of rope wheel and rope diameter should not be less than 20. There must be a manual sliding device which can make the hanging working platform drop down smoothly when the power is cut off.
There are two types of electric hoist, one is driven by electromagnetic brake three-phase asynchronous motor, after secondary deceleration drive wire rope conveyor so that working platform move up and down, another is also three-phase disc motor driven by electromagnetic braking, when deceleration, coaxial transmission drives wire rope working to move suspension platform up and down.