5 May 2017

Mounting of SCR

  • 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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