Thyristor is a controllable semiconductor device, which from the blocking state goes into the conduction state after giving a short control pulse to the thyristors gate.
DACPOL offers following type of thyristors:
Standard thyristors are suitable for the construction of converters operating at the frequency of 50 Hz power networks. They can be used for the construction of controlled rectifiers and power regulators as well as soft-starters.
Fast thyristors, also called impulse thyristors, are characterized by a short switching time, high resistance to steepness of conduction current rise and short time of switching off.
Thyristors are used in current inverters and voltage inverters, as well as in DC drive converters and induction heating.
Asymmetric thyristors are characterized by low backward and comparable voltage, with other types of thyristors, blocking voltage. They are used primarily in traction converters of drive systems.
Thyristors are offered in two types of housing: screw-fit and capsule shaped of various sizes. They are mounted on heat sinks adapted to the losses generated in the SCR during electric conduction. When installing thyristors, apply a thin layer of thermally conductive paste to their casing, which improves heat transfer properties to the heat sink.
Thyristors in a screw-fit casing should be screwed to the radiator so that their terminals adhere to the whole surface. Pulse thyristors are cooled by radiators adjacent to the pellet. The appropriate pressure of the radiators to the pellet is provided by a special construction buckle equipped with a pointer to control the clamping force.
Thyristors require protection against the effects of short circuits and switching overvoltages. Only quick fuses specially designed to protect diodes and thyristors can be used for short circuit protection. To protect the thyristors against overvoltages, a RC muffler, varistors and special semiconductor elements switched between the gate and the anode, e.g. BOD type, are used.