high temperature protection
❖ With the increase in the temperature of the junction, insulation may get failed. So we must take proper measures to limit the temperature rise.
Protective measures:
❖ We can achieve this by mounting the thyristor on heat sink which is mainly made by high thermal conductivity metals like aluminum (Al), Copper (Cu) etc.
❖ Mainly aluminum (Al) is used due to its low cost. There are several types of mounting techniques for SCR such as – Lead-mounting, stud-mounting, Bolt-down mounting, press-fit mounting, press-pack mounting etc
gate protection of thyristor
❖ Like a thyristor, Gate circuit should also be protected from overvoltage’s and overcurrent’s.
Protective measures:
❖ Overvoltage’s in the gate circuit can cause false triggering and overcurrent can cause high junction temperature.
❖ Overvoltages thyristor protection is achieved by using a zener diode and a resistor can be used to protect the gate circuit from overcurrent.
❖ Noise in gate circuit can also cause false triggering which can be avoided by using a resistor and a capacitor in parallel.
❖ A diode (D) may be connected in series or in parallel with the gate to protect it from high reverse voltage.
Password: Snubber
pdf made by Dr M Balasubbareddy