What is the reason why the magnetic force of the grinder’s electric permanent magnet sucker disappears
1. The electric permanent magnet sucker of the grinder opens the power distribution box of the machine tool
Test the power at both ends of the fuse with a test pen, and then use a multimeter AC 500V to measure the power supply voltage to 380V.
Turn off the main power switch, check whether the AC contactor is mechanically stuck, remove one of the coil wires of the contactor, measure the resistance at both ends of the coil with a multimeter electric barrier, and indicate that the coil is normal.
2. The grinder electric permanent magnet chuck is connected to the coil wire
Remove the undervoltage relay housing, measure the resistance at both ends of the coil, the dial is still indicating normal, indicating that the undervoltage relay coil is not broken, and then check whether the relay is mechanically stuck.
Then close the upper power switch, use the multimeter AC stop to measure the transformer sub-side voltage of 135 V, change the DC stop to measure the voltage at both ends of the rectifier diode, under normal circumstances, the DC voltage output of the bridge rectifier should be 110V, at this time there is no voltage output.
Disconnect the main power switch, use a multimeter to measure the four rectifier diodes separately, and find that two of the tubes are faulty. Weld the wire connecting the diode, remove the diode, and check the measurement again to prove that the tube has broken down. Replace the two new secondary tubes, connect the wires, and check whether the welding is firm.
Horizontal surface grinding machine with circular table
3. Turn on the main power switch
Use a multimeter DC gear to measure both ends of the rectifier diode, with a voltage indication, and its voltage value is 110V.
The operator presses the button of the grinding wheel motor to start the electromagnetic chuck switch, the workpiece can be sucked and the fault has been eliminated. Press the button of the grinding wheel motor to start the electromagnetic chuck switch, the workpiece can not be drawn, because the relay contact is interlocked, and the grinding wheel motor can not be started.
4. Open the power distribution box
Test the power at both ends of the fuse with a test pen, and then use a multimeter AC 500V to measure the power supply voltage to 380V.
Turn off the main power switch, check whether the AC contactor is mechanically stuck, remove one of the coil wires of the contactor, measure the resistance at both ends of the coil with a multimeter electric barrier, and indicate that the coil is normal.
Vertical surface grinding machine with circular table
5. The grinder electric permanent magnet chuck is connected to the coil wire
Remove the undervoltage relay housing, measure the resistance at both ends of the coil, the dial is still indicating normal, indicating that the undervoltage relay coil is not broken, and then check whether the relay is mechanically stuck.
Then close the upper power switch, use the multimeter AC stop to measure the transformer sub-side voltage of 135 V, change the DC stop to measure the voltage at both ends of the rectifier diode, under normal circumstances, the DC voltage output of the bridge rectifier should be 110V, at this time there is no voltage output.
Disconnect the main power switch, use a multimeter to measure the four rectifier diodes separately, and find that two of the tubes are faulty. Weld the wire connecting the diode, remove the diode, and check the measurement again to prove that the tube has broken down. Replace the two new secondary tubes, connect the wires, and check whether the welding is firm.
6. The electric permanent magnet chuck of the grinder closes the main power switch
Use a multimeter DC gear to measure both ends of the rectifier diode, with a voltage indication, and its voltage value is 110V. The operator presses the button of the grinding wheel motor to start the electromagnetic chuck switch, the workpiece can be sucked and the fault has been eliminated.
