What are the main factors that cause the failure of SMC insulation board

(1) Breakdown of gas

When the electric field strength of the SMC insulation board exceeds a certain value, it will cause gap breakdown. If the gap is too small, the electric field strength will increase and cause gas breakdown. Commonly, capacitors break down due to excessively high applied voltage, electric sparks caused by exposed wires, and arcs when the switch is closed. These conditions indicate that they no longer have insulating properties.

(2) Breakdown along the surface

In the use of SMC insulation board, there are often gas or liquid media around the solid medium, and breakdown often occurs along the interface of the two dielectrics and on the side with lower electrical strength, which is called creeping breakdown. The breakdown voltage along the surface is lower than that of a single dielectric. At the edge of the capacitor electrode, the insulator at the end of the motor wire (rod) is prone to creeping discharge, which causes great damage to the insulation and leads to failure.

(3) Breakdown of liquid dielectric

The electrical strength of the liquid dielectric is much higher than that of the gas under the standard state. If the oil contains impurities such as moisture, its electrical strength will be severely reduced, and it is easy to break down and cause the insulation material to fail.