Three - phase power supply phase sequence / open phase detector

Published:2012/8/24 22:28:00 Author:Ecco | Keyword: Three - phase , power supply , phase sequence, open phase, detector | From:SeekIC

It is mainly used to detect the three-phase AC power wiring with phase loss and correct phase sequence or not. Circuit schematic is shown in thefigure, in the figure, if the A -phase ( 1 ), C phase ( 3 ) , B phase ( 2) are respectively connected to the thyristor A , G, and K electrode, thyristor T will get conduction in singlephase half cycle, the light - emitting diode will emit normal light, when the three-phase phase sequence of connections A, B, C is incorrect, the conduction time of the triac T will become shorte , the average current decreases and LED brightness is also greatly reduced.When one or two phasesaremissed inthe three-phase AC, SCR iscut off, LED goes ou, the values of R3, R4 and C will determine the length of the delay time t.



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