Machine tool electrical equipment fault diagnosis steps - Database & Sql Blog Articles

Photocoupler

(1) Fault investigation Q: After the machine tool fails, the operator should first understand the forehand situation of the fault, which is beneficial to analyze the cause of the fault according to the working principle of the electrical equipment. The general inquiry is: Does the fault occur before driving, after driving, or when it is running? Is it self-stop during operation, or stopped by the operator after abnormal conditions are found; when the fault occurs, the working order of the machine tool, which button is pressed, which switch is pulled; whether the equipment is abnormal before and after the fault occurs (such as noise, smell, smoke or fire, etc.); whether there have been similar failures in the past, how to deal with them, etc.
Look: Whether the fuse in the fuse is blown, whether other electrical components are burnt, hot, broken, whether the wire connection screw is loose, and whether the motor speed is normal.
Listen: The sound of the motor, transformer and some electrical components during operation can help find the fault.
Touch: When the coil of the motor, transformer and electrical components fails, the temperature rises significantly, and the power can be turned off and then touched by hand.
(2) Circuit analysis According to the survey results, the electrical schematic of the electrical equipment is analyzed, the location of the fault is initially determined, and then the fault range is gradually reduced until the fault point is found and eliminated.
When analyzing faults, it should be targeted. For example, ground faults should first consider the electrical components outside the electrical cabinet, and then consider the electrical components inside the electrical cabinet. For open circuit and short circuit faults, the components with frequent motion should be considered first, and the remaining components should be considered.
(3) Disconnect the main power supply of the machine before checking the power failure, and then gradually find the fault point according to the possible parts of the fault. During the inspection, check the grounding and short circuit of the power supply at the incoming line of the power cord. Whether the fuse indicator of the spiral fuse jumps out or whether the thermal relay operates. Then check the external electrical damage, whether the connecting wire is broken, loose, and whether the insulation is overheated or burnt.
(4) When the power-on check is performed for the power-off check and the fault is still not found, the electrical equipment can be checked for power.
In the power-on inspection, the motor and the mechanical part of the transmission should be disconnected as much as possible, the controller and the transfer switch should be placed at the zero position, and the travel switch should be restored to the normal position. Then the multimeter checks if the power supply voltage is normal, whether there is a phase loss or a serious imbalance. Then check the power-on, the order of inspection is: first check the control circuit, then check the main circuit; first check the auxiliary system, then check the main drive system; first check the AC system, then check the DC system; close the switch, observe whether the electrical components are Act as required, whether there is fire, smoke, or fuse blown until the fault is detected.