MEASUREMENT OF LEAK CURRENT USING EFFECTIVE VALUE OPERATING TYPE VOLTAGE TRANSDUCER, AND AUTOMATIC MONITORING EQUIPMENT FOR LEAK CURRENT

• Main Author: MATSUOKA KIYOAKI
• Format: Patent
• Language: English
• Published: 26.08.1997
• Edition: 6
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To enable warning an alarm signal by making a second kind earth line of a trans former penetrate a zero phase current transformer, inserting a series resistor in the secondary circuit, measuring the terminal voltage of the resistor with a transducer, and obtaining a leak current value from the terminal voltage. SOLUTION: When insulation of an electric load 16 is deteriorated, a leak current flows to the earth through an earth line 17. Similarly a leak current flows in a second kind earth line 3, and a secondary side current proportional to the leak current is generated in a zero phase current transformer which the earth line 3 penetrates. The secondary side current flows through the resistor 6, an AC voltage is generated across both ends of the resistor 6. The AC voltage is inputted in an effective value operating type transducer 8 through a voltage detection circuit 7, and an output value proportional to an input AC voltage is inputted in a sequencer 10 through an output circuit 9. The sequencer 10 obtains the leak current from the inputted value. When the period that the leak current exceeds a safety specification value becomes longer than or equal to a specified value, an automatic telephone transmitter 12 is operated through a command circuit 11, and informs a pattern 14 of contract on entrasted inspection business of the state through a telephone line 13.