| 摘要 |
PURPOSE:To monitor the state of insulation in a hot line by connecting a central grounding coil to the power source terminlas and detecting difference of the current in both half coil sections that have the central point of the coil between themselves. CONSTITUTION:The voltage of a power source is applied between terminals A and B. When the insulation state of an electric circuit is good, an equal voltage is applied between points c and D and between points D and E, because an equilibrium state is maintained. If, for instance, the insulation resistance on the A side is lower, the voltage between D and E is determined according to the resistance to earth of the insulation resistance, and also the secondary voltage of a transformer T2 is determined accordingly. An alarm can be sounded by any resistance in the range of 0-infinity OMEGA of the secondary voltage of T2 by changing over the tap t and the regulation of a sensitivity regulation resistance Ro and according to the relation with the operating voltage of hot couples 1. In this way the state of insulation of an electric circuit that is not grounded can be continually monitored in the state of hot line. |
