| 摘要 |
Each of three phases has a separately arranged check-up channel of a current transformer (11, 21, 31) being connected to a full-wave rectifier (12, 22, 32) that is in turn connected to an OR diode (19, 29, 39) and at the same time to a stabilizer (13, 23, 33), which is grounded via a resistor (10, 20, 30). The stabilizer (13, 23, and 33) is connected to a first input of a comparator (14, 24, 34) that is connected to a first monostable circuit (15, 25, and 35) with prolongation of unstable state. The monostable circuit (15, 25, 35) is connected to a counter with oscillator (16, 26, 36), which is connected to another monostable circuit (17, 27, 37) being in turn connected to the first input of a two-condition indicator (18, 28, 38) with magnet. Outputs of the summing diodes (19, 29, and 39) are connected to a power supply unit (1) and to reference voltage supply unit (2). Said reference voltage supply unit (2) output is connected to second inputs of comparators (14, 24, and 34). Outputs of the monostable circuits (17, 27, 37) are connected to the first, second and third input of an OR circuit (3), the output of which is connected to input of a block (4) of the counter with oscillator. Said counter with oscillator block (4) output is connected to a manual resetting circuit (5) output. The mutually interconnected output of counter with oscillator block (4) and the manual resetting circuit (5) output are connected to the fourth input of the OR circuit (3). Output of the counter with oscillator block (4) is connected to resetting inputs of the monostable circuits (17, 27, and 37) and to resetting inputs of the two-condition indicators (18, 28, 38) with magnet.
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