| 摘要 |
A sequential controller is provided for sequencing multiple electric loads such electric pumps. That is, for each cycle the next load is designated as the lead load in a round-robin fashion. The controller uses cost effective electro-mechanical relay logic an thus avoids conventional solid state technology. In order to sequence the loads on each successive cycle, the electro-mechanical relay connected to the sensors comprises a double-throw contact set. The double-throw contact set comprises two complementary contacts, both of which alternate between normally open and normally closed on each successive cycle. In this manner one each successive cycle, the pumps designated as the lead pump and the lag pump automatically alternate in a round-robin fashion. Further, when the lead pump is disabled the lag pump is immediately actuated without disruption of service.
|
