| 摘要 |
PROBLEM TO BE SOLVED: To provide a power source monitor, a power source device and a power source monitoring method capable of blocking an adverse current in a simple constitution or safely and surely performing the supply of a power source. SOLUTION: The presence and direction of current flowing between an outside commercial power source 20 and load 30 are detected by a current transformer(CT) 11, and the polarity of the voltage of a voltage detection end VREF1 is detected by an adverse current detector 13. On the basis of the detection result, when the adverse current detector 13 judges that the adverse current occurs in the primary winding of CT 11, the current path of a relay 12 is cut off by timing in which current does not flow. When the current does not flow in CT 11, the adverse current detector 13 forms the current path between the voltage detection terminals VREF2 and VREF3, and detection current is passed to the current path and the primary winding of CT 11. The current path of the cut-off relay 12 is connected again when the adverse current detector 13 judges that the voltage of the commercial power source 20 and the voltage of a generator 14 change in the same phase. |
