Libratherm offers SCR triggering cards model LTC-12 & LTC-13 designed to fire or trigger back to back connected SCRs using synchronized phase angle control technique. The card accepts analogue control signals like (0 5) VDC or (4 20) mA and provides proportional gatecathode pulses G1K1 + G2K2. These pulses can be used to trigger back-to-back connected SCRs of as high as 350Amperes. The card also provides built in regulated 5VDC supply to connect external potentiometer to manually control the SCR firing. LTC-12 and LTC-13 are same in all respect, except the card LTC-13 accepts the feed back signal from the external current transformer for the current limit and trip features. This feature is useful for transformers or inductive loads or heating loads like Silicone Carbide and Molybdenum which exhibits significant changes of resistance with increase in temperature. Both these cards can be used for heating control applications to control the AC power to the heating coils or to the transformers. Three such cards can be used for both 4 wire star and 6 wire delta configurations of the heating loads. LTC 14 SCR triggering card is available in DIN rail compatible module and which can also be used to trigger triacs.
Newly designed compact Three Phase SCR Triac triggering card model LTC-15 is used to fire three pairs of back to back connected SCRs or three numbers triacs configured as three phase - 4 wire star with neutral or 6 wire open delta. The entire assembly is available on either MS powder coated plate or on 6-mm. thick Bakelite sheet, which can be mounted inside the panel using 4 screws.
Libratherm also offers ready to use Thyristor power pack modules ranging from 15 amps upto 350 amps for single phase, 2 phase and 3 phase heater load. The power pack module comprises the triggering card, suitably rated back to back connected SCR module - mounted on the appropriately rated air cool or forced cool heat sink, input and output clip-on type heavy duty connectors, etc. The entire assembly is mounted on either MS powder coated plate or on heavy duty Bakelite sheet, which can be easily mounted inside the panel as desired. Complete ready to use control panel with suitable temperature control panel can also be supplied as per the users specifications and requirement.

ApplicationThe thyristor power pack has a varied application and can be used with heating elements like kanthal, super kanthal, silicon carbide, molybdenum infra red etc. Where precise and accurate power control is required. There is significant power savings with respect to conventional contractor type temperature control system which also depends on various other factors