electricity gantry crane
Talking about the electrical safety problems temporary electricity in gantry crane construction site
More of the installation and use of gantry crane is in the End of main stage, after the demolition of tower crane, The temporary power consumption at the construction site is more lax in this stage:
- Winch under the fuselage is not connected to the PE line, or although there are PE lines, but it is not fixed, easy to loose, Zero protection effect can not be guaranteed.
- Hoist do not repeat grounding, if any, some grounding body also not in accordance with the requirements of specification and round steel or Angle, and replace with rebar, the grounding resistance can not meet the specified value.
- There is no isolating switch in the switch box, and can not use the electric equipment to carry out the power isolation during the daily maintenance . The leakage current in the switch box is too large, not in accordance with the norms of rated leakage action current 30mA, Rated leakage action time 0.1s to select, etc.
- When standing rectangle gantry lifting materials, there is no fixed hanging blue material measures, easy operation and the frame body produce interference, and can’t prevent slippery material (roll).
- The tests also found, when the gantry crane drops, some hoist operation by rolling, is a serious illegal operation. < Building hoist safety procedures> prohibit the use of “human open brake power control implementation of rolling, is a serious illegal operation. < Building hoist safety procedures>Prohibit the use of human power control to implement rolling on the brakes. Otherwise, the landing speed is too fast, too fast brake etc., Will cause the damage of hanging basket, hanging basket derailment, frame body open welding deformation and other equipment and the personal accident.
- Winch operator from the machine, the basket does not fall to the ground, do not cut off the power supply.
- The winch operator does not rectify the irregular arrangement of the steel wire rope on the drum, the steel wire rope after the force of mutual extrusion, The dead bend, the rope core extrusion, the rope structure destruction and so on, thus destroyed the steel wire rope force condition.