Wire rope hoist the eight electrical safety protection device
1, the main isolating switch
Wire rope gourd into the line at a main isolating switch, disconnect the main isolating switch crane without electricity, to ensure the safety of the repair and maintenance personnel. The ground operation small single girder cranes (low headroom electric hoist cranes) from time to set the main isolating switch.
2, the emergency switch
Emergency switch should be installed in the driver reaches the position, (some point disk crane electric disk using the same model with the emergency switch switch control, electric disk control switch can not be installed side-by-side with the emergency switch) to prepare for an emergency situation, the rapid disconnect the total power to ensure the safety of personnel and equipment.
3, short-circuit protection
Fuse, automatic air switch two commonly used short-circuit protection device. Should be set back on the road in total power, short-circuit protection of the total power supply circuit.
4, zero protection
To prevent agencies controller failed on zero, the driver suddenly start accident power transmission vehicles, crane controller has zero protection.
5, the loss of field protection
No current DC his machine motor, he excited the exciting winding armature current dramatic increase caused by the fault. Another example crane hoisting mechanism governor eddy current brake, eddy current brake loss of field load decreased speeding phenomenon. In both cases, the loss of field protection should be set.
6, overcurrent protection
DC motor armature circuit in series AC motor stator back on the road, over-current relay. When the current exceeds the allowable value, the relay operates the motor power, played the role of motor protection.
7, interlock protection
In the crane cab doors, access doors, the hatch door upstream or escalators mouth at setting the trip switch, these limit switch is open, automatically cut off the power, the whole crane can not start, in order to protect the safety of personnel.
8, ground fault protection
In order to prevent personnel injury by electric shock when the crane metal framework charged set ground protection.
Cross-section of the grounding cable to use not less than 150mm2 flat steel or 10mm2 copper wire connected by welding. Non-ground wire for the zero line of the carrier. Its shell with crane lifting electromagnet powered by the AC mains rectifier, should be a reliable electrical connection. Should be a reliable electrical connection between the metal shell and crane hanging control button (electric hoist cranes flashlight door). Cranes and track any point on earth resistance value shall not be less than 4.