| 摘要 |
Controller for a steam generator has two safety relays (10, 11) for the safety power supply (7). Parallel to the relays are shunt connections (11, 12, 14; 12, 13, 14). To test the relay switching both are switched to their off position and the voltage change monitored. If an incorrect voltage signal is produced an error signal is generated. During testing the safety power supply passes through the parallel shunt connectors. To control the safety relays switching amplifiers (27, 28) are provided with a response time that is a fraction of the response time of the relays. To test the electrical control of the relay drives (21), the relays are switched in a current free manner and the voltage change monitored. An error signal is produced if there is not a sufficient voltage change. During this test the relays remain in operating mode. |
