As an important part of the induction melting furnace, the silicon controlled rectifier (SCR) often burns out. How to ensure the safety of the SCR? It is necessary to find out which factors are usually caused by the burning of the SCR, and then the right medicine can be prescribed. Below, Luoyang Judian will analyze the reasons and solutions for SCRs burning.
Analysis of the Reasons for Silicon Controlled Rectifier Burning
The heat dissipation effect of the water-cooling jacket or the internal water cut-off effect is reduced
Sometimes due to water quality problems, a layer of scale will adhere to the wall of the water-cooling jacket. In this case, although the water output and pressure are sufficient, the heat dissipation effect will be greatly reduced because of the poor thermal conductivity of the scale. In this case, the water-cooling jacket should be replaced in time.
The connecting wire of the silicon controlled rectifier is disconnected or in poor contact
When the power rises to a certain value, there will be a sparking phenomenon and an instantaneous overvoltage will be generated at both ends of the SCR. If it is too late for the overvoltage protection action at this time, the components of the SCR will be burned out. It is necessary to check the connecting wire of the tank circuit frequently and decide whether to repair or replace it according to the actual situation, so as not to affect the normal operation of the equipment.
Trigger pulse loop failure
If the trigger pulse is suddenly lost when the device is running, it will become an open circuit of the inverter, and the high voltage generated by the output terminal of the intermediate frequency power supply will burn out the controllable components. This situation can be checked with an oscilloscope to determine whether it is a problem of poor contact of the inverter pulse lead wire and shake the connector of the wire to find out the fault location.
The load is open or short-circuited when the equipment is running
If the device is running at high power, no matter whether the load is suddenly in an open circuit or short circuit state, the high voltage or short circuit current impact formed at the output terminal may burn out the SCR element. When a problem is found in the inspection, the equipment should be stopped in time to avoid burning out the components.
The protection system doesn’t work
If the equipment is slightly abnormal during work and the protection system fails, it may cause problems with the SCR. The protection system is mainly used to protect the safety of the SCR. The protection system should be inspected regularly to troubleshoot in time.
The Solution to Silicon Controlled Rectifier Burning
The resistance-capacitance absorption circuit of the inverter tube, so it is necessary to carefully check whether the absorption capacitor is an open circuit. If the inverter absorption circuit is disconnected, the inverter tube will be easily damaged.
Make sure that the electrical parameters of the inverter tube meet the requirements for use, and it is strictly forbidden to use components from unqualified manufacturers.
Check the water jacket of the inverter tube and other cooling water channels for blockage, which is easily overlooked.
Check whether the load is sparked to the ground. In this case, a sudden high voltage will be formed, which will cause the breakdown and damage of the inverter tube.
If the operating angle is too large or too small, it will cause frequent overcurrent of the inverter tube, which will damage the tube and cause permanent damage.
The above are the reasons and solutions for the burnout of the SCR in the intermediate frequency melting furnace. I hope it can be helpful to you.
