| 摘要 |
PURPOSE:To protect a load by multipoint-connecting first and second relays between a power receptacle and the load in such manner that the first relay does not operate but the second relay operates at the rated supply voltage of the load and the operation time of the second relay is longer than that of the first relay. CONSTITUTION:When a power receptacle CN is properly connected with the receptacle RCb of the subtrunk line Lb of AC24V, a first relay R1 does not operate but a second relay R2 supplied with power via the normally-closed contact R1b of the first relay operates so that a load L can be supplied with a rated supply voltage AC24V via the normally-opened contact R2a of the second relay R2 to operate normally. In this case, further, the second relay 2 has an operation time longer than that of the first relay, there is no possibility of the second relay R2 operating earlier than the first relay R1. Thus, the load L can be protected surely. |
