- When the current passes through SCR is greater than the rated value, the thermal stress produced in it which generates mechanical force.
- If this mechanical force does not control, the SCR may damaged.
- The protection of the SCR in such a condition is done by proper mounting of it. The mounting method depends upon the rating of the SCR.
Lead mounting
- This method is used when load current is of small value.
- The SCR does not require cooling device or heat sink in this method because most of the heat is dissipated by radiation and convection.
Bolt mounting
- There is one hole is provided in the SCR.
- The heat sink and SCR are joined by the bolt.
- The mica or fibre insulation is kept in between the heat sink and SCR. This type of mounting is used in the small and medium rating SCR.
Stud Mounting
- There are two molybdenum plates kept on both sides of SCR.
- The anode is soldered with aluminium resulting one stud is created. The SCR is joined to heat sink by this stud.
- If there is not necessary electrical isolation, mica or fibre type washers are used.
- The conduction of heat is done easily though mica or fibre type washers. It will also works as electrical insulator.
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