Detailed Product Description

PRODUCT DESCRIPTION:

Libratherm offers four channel SCR firing cards model SCRF-4 for Heating control applications using resistive or inductive loads. Normally the solid state relays are built around triacs and are available up to the current carrying capacity of maximum 50Amp to100Amp @ 230VAC due to limitations of high PIV as compared to SCR. Normally, for controlling higher ratings of load, power contactors are used and solid state switching is not easily accomplished. The card SCRF-4, featured here can be used to fire up to 500Amps SCRs. Hence it is possible to built solid state relay of as high as 500Ampere @ 230VAC or415 VAC. The input control signal coming from the temperature controller in the range of 3 to 32VDC can be fed to this card to generate ZERO cross over Gate to Cathode pulses G1K1+G2K2 to turn ON the SCR, and it can be turned off when the input signal is 0VDC. ZERO cross over circuit prevents generation of harmonics while turning the SCR OFF to ON or vice versa.

Using the single card, 4 independent SCRs can be fired in single phase, two phase or three phase load in star or delta configuration. User has a choice to select suitable ratings of the SCR as per the load current (with suitably rated heat sinks). Making the solid state relays using this card is more advantageous, since, rapid on/off switching of the order of 1 second is possible, when compared to the power contactors. The card SCRF-4 is available in DIN mounting card holder. Proposed single phase and three phase wiring diagrams are attached.

TECHNICAL SPECIFICATIONS: