PURPOSE: To shut off automatically and sequentially a current protecting device of an electronic exchange by providing a control circuit for controlling an overcurrent protecting device and a timing circuit which drives at every certain interval when it receives a start signal from the outside.
CONSTITUTION: A trip action of an overcurrent protecting device (NFB)5 is as follows: when a power source of negative 48V is shut off in a power chamber 4a, or when a key OP is operated; a relay A, a relay B and a relay W are sequentially actuated. A relay C is restored by the action of the relay B. The relays B and C alternately repeat the action and restoration accordingly. Moreover, a relay X is actuated due to the restoration of the relay B. While the relay B performs the action and the restoration twice, the relays W and X act one time. A control of the NFB5 is as follows: the relays W and X act alternately due to the action of the relay B, and operate from a relay 10 to (n) by a certain interval. At this point an earth closed circuit across an exchange 6 of negative 48V, a contact point 10c, the NFB5 and the power chamber 4 is formed by the action of the contact point 10c. A coil of the NFB5 releases a contact point 5a in said circuit. As a result, a power source unit 3 stops supply of a power source to a load circuit 2.
| JPS6192094 | CIRCUIT DEVICE FOR SMALL-SIZED CONSTITUTION EXCHANGE |
| JPS59114989 | FEEDING SYSTEM |
| JPS6367095 | POWER SOURCE SEPARATING SYSTEM IN TRUNK CONTROL |
KANAO SEIICHI
OSAKABE YOSHITAKA
KITAZAWA MITSURU
TSUCHIDA SHINOBU
NIPPON TELEGRAPH & TELEPHONE
NIPPON ELECTRIC CO
HITACHI LTD
FUJITSU LTD
| JPS5549707A | 1980-04-10 |