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LZF-3 – Three Phase Zero Cross Over thyristor Triggering / SCR Firing Card for 2 leg or 3 leg control.
Libratherm offers Three Phase SCR Firing Card LZF-3 for switching power to single-phase and three-phase operated electrical resistive or inductive loads. This Zero Cross Over Thyristor Triggering Card is basically developed to replace the electro-mechanical contactors with the solid-state switch built using silicon controlled rectifiers (SCRs). When the electrical load is operated through contactors – the AC cycle is switched ON or OFF at any point of 0 to 180-degree phase angle, this leads to the generation of arcing on the contacts and may generate harmonics, which can cause an electromagnetic disturbance in the power lines and can also cause malfunctioning of other electronic instruments on the panel. The SCR Firing Module featured here eliminates the generation of such harmonics because of the zero cross over switching technique, also no arcing or audible noise will be observed during the switching operations – since no mechanical switching contacts are involved in the solid-state device.
LZF-3 accepts 3 independent or one common linear signal of 4-20mA/0-5V/0-10V/Potentiometer or DC pulse/Contact input from temperature controller or from PLC and generates 3 independent gate cathode triggering pulses (G1K1+G2K2) for 3 pairs of back to back connected SCRs. Hence, one can control 3 independent single-phase loads or a single 3 phase load in star or delta configuration. The linear signal is pulse-width modulated to generate pulsating output with the variable on/off duty cycle time of 2 to 30 seconds adjustable using on card potentiometer.
|Item||SCR Firing Card with ZERO Cross overturns ON for single phase or 3 phase load.|
|Control Input||Control Input 12 to 36VDC or potential free contact or
|4-20mA/0-5V/0-10V – user selectable using DIP switch.|
|No. of Inputs||No. of Inputs Common for all 3 outputs or individual for each output.|
|Each analog input can be selected for 4-20mA/0-5V/0-10V using on card DIP switches.|
|Triggering Pulses||Gate/ Cathode pulses - Optically isolated from the Input -
suitable to fire 25A to 500A back to back connected SCRs.
|G1K1+G2K2 X 3 = 12 pulses.|
|No. Of Outputs||3 independent Back to Back SCR can be triggered.|
|Load Configuration||a) 3 independent single phase AC load w.r.t. neutral|
|b) 3 independent two phase AC load w.r.t. second phase.|
|c) Single 3 phase star or delta connected load.|
|Supply Voltage||230VAC +/-10%, single phase, 50/60Hz.|
|Output Line Voltage||110VAC/230VAC/415VAC or any other lower line voltage from step down transformer.|
|Mounting||35 mm. DIN rail or can be screw mounted on the panel surface.|
|Size (H x W x D)||125 x 185 x 65 mm.|
|Model||Product Description||Part No.|
|LZF-3||3 phase zero cross over SCR firing card for 2 leg or 3 leg control.||2201|