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Analysis of Electric Capacitor Fault in Medium Frequency Induction Furnace

2023-04-06

1. Internal ignition of capacitors: When the machine is running, there is a noise inside, indicating insulation breakdown. It should be replaced with a new one.

 

2. Capacitor external ignition: When the machine is running, the external ignition causes poor insulation of the capacitor shell to the ground or the series capacitor with series and parallel boosting to be connected to the parallel capacitor shell.

 

3. If heating insulation is damaged due to blocked cooling water, it shall be handled in time. Insulation inspection of electric heating capacitors. The insulation resistance of capacitors is divided into two poles, multi-stage insulation groups, and insulation resistance between the two poles and the shell. As capacitors are composed of series and parallel capacitor components, the insulation degradation of individual components will not lower the insulation resistance of the entire capacitor. Therefore, it is difficult to detect defects in the insulation resistance between remote sensing poles. Therefore, this test is generally not conducted, but only for the measurement of insulation resistance between two poles or multiple levels of the shell. Use different voltage trameggers based on the rated voltage. Taking the rated voltage of 750V as an example, using a 1000V tramegger, the capacitor should be discharged before shaking the side. When shaking the side, the dial should first be shaken to the specified speed, and after the pointer stabilizes, the dial should be connected to the two poles of the capacitor before continuing to rotate the dial. At the beginning, due to charging the capacitor, the pointer will decrease and then slowly rise until it stabilizes. At this point, the reading is very similar to the inter pole resistance of the capacitor, and generally, 1000V should not be less than 1 megohm. After reading the numbers again, you should first remove the shake line and stop shaking. Otherwise, due to the discharge of the capacitor, it is easy to burn the meter head. After telemetry, the capacitor should be discharged to avoid electric shock.