The electric chain hoist includes two parts: wire rope electric hoist and electric chain hoist, which plays an important role in the lifting machinery industry. Fire stop limiter is an important accessory in the electric chain hoist. When the lift hook rises or descends to a certain limit position, it will push or pull the push rod on the fire stop. The dynamic and static contacts are broken and the main power supply is cut off, thereby limiting the position.
The failure of the electric chain block stop limiter will cause it to operate incorrectly. Therefore, measures should be taken to prevent failure of the electric chain hoist stop limiter. When using, it is strictly prohibited to pull the oblique slant, because the slant will cause the rope guide lateral force, resulting in breakage and damage to the rope guide. The upper and lower limiter of the fire stop can be tightened in place after being properly adjusted to prevent the looseness from changing the position of the high limit and the low limit.
The fire limiter on the electric chain block is correctly wired. There are 5 wires. The B phase is the common line. The AC phase of the contactor is connected to the terminal on one side of the push rod, and the other side is connected to the AC phase line of the contactor. If this position is reversed, when the up limit pusher touches the fire stop, the electric chain hoist can still rise but cannot go downwards. On the contrary, when the down limit pusher touches the cutoff limit, When the positioner is on, the electric hoist can still fall but cannot go upwards.
The selection of the rated current of the electric chain hoist preventive limiter must be greater than the operating current of the electric chain hoist, at least 1.5 times the operating current. Later, for this example, the electric chain hoist control ring was improved and a main power contactor was added.
In the past, there was no main power contactor in the electric chain block control box, and the emergency stop switch of the control handle only cut off the control power supply, and there was no protection effect on the contactor stuck or stuck. When the electric chain hoist is in use, after the main power contactor is added, the emergency stop switch on the control handle should be used to control its on and off, which can effectively prevent accidents caused by the lifting contactor being unable to disconnect.