Induction melting furnace Electrothermal capacitor failure analysis
1. Internal ignition of the capacitor: When the machine is running, there is a sound inside, it is insulation breakdown, it should be replaced.
2. External ignition of the capacitor: When the machine is running, external ignition, the capacitor housing is not well insulated to the ground or the series capacitor connected in series and parallel is connected to the parallel capacitor housing.
3. If the cooling water does not pass, it will cause damage to the heating insulation and should be disposed of in time. The insulation resistance of the electric heating capacitor is divided into two-pole, multi-stage insulation group and two-pole insulation resistance. Since the capacitor is composed of series and parallel capacitors, the insulation degradation of individual components will not be The insulation resistance of the entire capacitor is reduced, so it is difficult to find defects in the insulation resistance between the remote electrodes. Therefore, this test is generally not done, and only two or more levels of insulation resistance of the outer casing are measured. Different volts of the shaker are used depending on the rated voltage. Now take the rated voltage of 750v as an example, use a 1000v shaker, and discharge the capacitor before shaking the side. When shaking the side, first shake the shaker to the specified speed. After the pointer is stable, connect the shaker to the two poles of the capacitor and continue to rotate the table. At first, because the capacitor is charged, the pointer will drop, and then slowly rise until it is stable. The reading at this time is extremely the resistance of the capacitor. In general, 1000v must be no less than 1 megohm. After reading the number, you should first remove the shake line and stop shaking. Otherwise, the meter is easily burned out due to the discharge of the capacitor. After telemetry, the capacitor should be discharged to avoid electric shock.
