What are the electrical wire rope hoist safety

Wire rope hoist lifting equipment as the most widely used, frequently one of the devices, the problems are also diverse, in order to avoid the appearance of using fault,
1, short circuit protection: Short circuit protection devices are commonly used in fuses, automatic air switch two kinds. Should be set at the main power back on the road, to the total power supply circuit to do short-circuit protection.
2, zero protection: To prevent the agencies failed to put the controller zero, the driver suddenly start sending electric vehicle accident, the crane on each controller has zero protection.
3, loss protection: his machine in the DC motor field winding excited he is no current, the armature current will surge caused failure. Another example is the use of  lift hoist  mechanism when speed eddy current brake, eddy current brake load down speeding causes loss of excitation phenomena. In both cases, should be set loss protection.
4, overcurrent protection: back on the road in the AC motor stator, DC motor armature circuit in series overcurrent relays. When the current exceeds the allowable value, the motor power relay, played on the motor protection.
5, interlock protection: in the crane cab doors, access doors on the hatch door up or escalator mouth, set the limit switch, the limit switch is turned on, automatically cut off the power supply, the whole crane can not be switched on in order to protect personnel safety.
6, ground protection: To prevent the crane metal structures energized by an electrical shock personnel, setting ground protection.