PURPOSE: To stabilize a power source at the time of short circuit, precisely detect cable information, and improve assembly property by using a current detecting device having two current devices for detecting a current having smaller than a determined standard value and a current larger than the determined standard value, respectively.
CONSTITUTION: When the current of a cable is smaller than a standard value, the output signal of a current detecting circuit 1 having a first current transformer 8 is processed in a control circuit 3 to output cable information such as current value and power. When the current is larger than the standard value, the output signal of a current detecting circuit 2 having a second current transformer 9 is compared with a set level, and when it exceeds this level, the detection signal of overcurrent is tripped, and inputted to a circuit 5 to start tripping a device. At the time of short circuit, the output signal of the circuit 2 is directly inputted to the circuit 5. Although the voltage between phases is lowered, the output of the circuit 4 can be stabilized since the output of the current transformer 9 is inputted to the power source circuit 4.
AOYAMA YOICHI
MATSUDA JUNICHI
OKADA TAKEHIKO
| JPS6013419A | 1985-01-23 | |||
| JPS6098818A | 1985-06-01 | |||
| JP53160128A | ||||
| JPS5795125A | 1982-06-12 | |||
| JPS53122571A | 1978-10-26 |