The inspection steps are:

 

 

 

1. Investigation: ask the operator and the personnel on site about the fault, including the external performance of the fault, the general position and the environment in case of fault. If there is any abnormal gas, open fire, whether the heat source is close to the high and low voltage power distribution equipment, whether there is corrosive gas intrusion, whether there is water leakage, whether someone has repaired it, the content of repair, etc.

 

 

 

2. Preliminary inspection: according to the investigation, check whether there is any damage to the exterior of the high and low voltage distribution equipment, whether the wiring is open circuit, loose, whether the insulation is burnt, whether the fuse indicator of the screw fuse jumps out, whether the high and low voltage distribution equipment has water and oil dirt, and whether the switch position is correct, etc. During test run, further test run can be conducted after preliminary inspection to confirm that the fault will be further expanded and personal and equipment accidents will be caused. During test run, attention shall be paid to whether there are serious fire, abnormal smell, abnormal sound and other phenomena. Once found, stop the vehicle immediately and cut off the power supply. Pay attention to check whether the temperature rise of the high and low voltage distribution equipment installation and the action procedure of the high and low voltage distribution equipment meet the requirements of the schematic diagram after the installation of the power equipment, so as to find the fault position.

 

 

 

Inspection method: observe the sparks. The contacts of high and low voltage power distribution equipment will produce sparks when they close or break the circuit or the wire ends are loose. Therefore, check the faults of high and low voltage power distribution equipment according to the existence and size of sparks. For example, if sparks are found between the normally tightened wires and screws, the thread head is loose or in poor contact. When the contacts of high and low voltage power distribution equipment close and break the circuit, the fire jump indicates that the circuit is on, and the non fire jump indicates that the circuit is not working. When there is spark between the main contacts of the contactor of the control motor and there is no spark between the two phases, it indicates that the contact of the non sparking one phase is poor or the circuit of this phase is open circuit; the spark of the two phases in the three phases is larger than normal and the other is smaller than normal, which can be preliminarily judged as the short circuit between phases or grounding of the motor; the three-phase sparks are larger than normal, which may be the motor overload or the mechanical part is stuck. In the auxiliary circuit, after the contactor coil circuit is powered on, the armature does not close. It is necessary to distinguish whether the circuit is open or the mechanical part of the contactor is stuck. Press the start button once, for example, there is slight spark when the normally open contact closed position of the button is open, indicating the circuit path, and the fault is in the mechanical part of the contactor; if there is no spark between the contacts, indicating the circuit is open.

 

 

 

Action procedure: the action procedure of high and low voltage distribution equipment shall meet the requirements of mechanical and electrical instructions and drawings. If the high and low voltage distribution equipment on a circuit acts too early, too late or does not act, it indicates that the circuit or the high and low voltage distribution equipment is faulty. In addition, the fault can be analyzed and judged according to the sound, temperature, pressure, smell and so on. By using the intuitionistic method, not only the simple faults can be determined, but also the more complex faults can be reduced to a smaller range.