Libratherm offers ready to use thyristor power switch for On-Off switching of electrical heating loads ranging from 20KW to 720KW 3-phase. This power switch modules comprises Libratherm make SCR triggering card model LZF-3 or TSC-307, suitably rated back to back or inverse parallel connected SCR modules (with electrically isolated base)- mounted on the suitable size of Aluminum heat sink duly fitted with the cooling fan/blower, 3 phase AC Supply Input and Load Output Aluminum/Copper bus bars and over temperature thermal cutouts. The entire assembly
is mounted in an MS enclosure, which in turn can be easily mounted inside the closed control panel as desired.

All models of thyristor power switch accept both analogue and digital control signal from DDC, PLC or PID controller to switch the AC power. The PWM duty cycle is adjustable by the user using on board potentiometer. Following diagram shows the switching pattern of thyristor with respect to the analogue control signal.

Complete ready to use control panel with suitable PID / Program temperature controllers can also be supplied as per the user specifications and requirement.

Key Features:

• Digital zero cross over Firing Cards for single phase/two phase/three phase are Field-
  proven for 25+ years.
• True zero cross over firing prevents generation of high voltage spikes and surges.
• Semikron – Germany / Proton – Russia make SCR Modules – SKKT / MT5 Series are used
  for AC to AC control and SKKT / SKKH Series are used for AC to DC control.
• Heatsinks are mounted with thermistors to protect against overheating and auto cut-
  off of firing in case of over temperature.
• Separate auxiliary supply of 230 VAC with built in RFI/EMI filter – Thereby electronics is
  safe against line voltage fluctuations and RFI/EMI electrical noise.
• SCR Modules are protected by suitable RC snubbers and surge suppressors.
• High-speed ball bearing type cooling fan/blower – To keep Thyristor stack cool within
  the acceptable limits.
• Built-in safety fuse for cooling fan and Auxiliary supply.
• Rugged metal enclosure & modular design – easy to install & easy to maintain.
• Libratherm Thyristors are time tested & field-proven in all major industries since last
  25+ years.
• More than 1000 installations have taken place across India & abroad and the number is
  growing rapidly.
• Usage of best in quality components since we understand that downtime and service
  cost is more expensive than the cost of the product.