In many audio-visual and electronic industries, SMC iron cores are used. However, how to eliminate SMC iron cores when they fail is a problem that needs to be solved in a timely manner. After some professionals have summed up the experience, the following solutions are obtained.
(1) Thorough overhaul measures. After monitoring the existence of multi-point ground failure, for the transformer that can be stopped, it should be stopped in time, and after exit, the multi-point ground failure should be completely eliminated. In order to eliminate this kind of failure, according to the multi-point ground type and the reason, appropriate maintenance measures should be taken. However, there are also some situations where the failure point can not be found after the power outage. In order to accurately find the location, the following method can be used on the scene.

　　1 DC method. Open the joint between the core and the clamp, pass 6V DC on the Silicon steel plates on both sides of the yoke, and then use the DC voltmeter to measure the voltage between the Silicon steel sheets in turn. When the voltage is equal to zero or the table indicates the reverse, It can be considered as a fault location.
2 Exchange method. The low-pressure winding of the iron core is connected to the AC voltage of 220 to 380V. At this time, a flux exists in the iron core. If there is a multi-point ground failure, the current will be measured with a milliammeter(the connecting piece of the iron core and clamp should be opened). The milliammeter is measured point by point along the iron yoke levels. When the current in the milliammeter is zero, this is the fault point.
(2) Temporary exclusion in the event of failure:
There is an external lead line. If the fault current is large, the ground line can be temporarily opened. However, surveillance must be strengthened to prevent the suspension potential of the core after the failure point disappears.
2 If the multi-point ground fault is an unstable type, a sliding wire resistor can be strung into the working ground line to limit the current to below 1A. The choice of sliding resistance is to divide the measured voltage on the normal working ground line by the current on the ground line.
The gas production rate at the fault point should be monitored by chromatographic analysis.
4 After the exact fault point is found by measurement, if it can not be handled, the normal working ground plate of the iron core can be moved to the same position at the fault point to greatly reduce the circulation.
The above is about the introduction of SMC core, I hope it can be helpful to you, if there is any doubt about the above introduction, you can call to consult