Thyristorised Phase Angle Power Pack
This is a power drive unit to drive resistive heaters of different capacities.
There are basically Silicon Control Rectifiers connected back to back with surge suppressor in form of metal oxide
varistors.
These switching devices are controlled by input signal of two types, 4-20mA or 0-5V. This signal in-turn controls the firing angle of the AC Phase.
The control circuit has a soft-start circuitry built in to avoid thermal jerks on the heaters. These power packs are available for single/three phase configuration range from 1KW to 1000KW(with fan cooling).