GB622505A - Automatic change-over relay systems for supplying current from a spare current source upon the failure of a main current source - Google Patents

Abstract

622,505. Systems depending on the use of two or more sources. WILCOLATOR CO. Dec. 24, 1946, No. 37902. Convention date, Feb. 1, 1945. [Class 38 (iv)] [Also in Group XXXVII] In a supply system in heavy aircraft, in which a spare inverter is brought into operation upon failure of the main inverter, an arrangement of relays, including a time-delay relay, ensures that the spare inverter is not energized on starting up unless the main inverter is definitely out of action. When switch 32 is closed, relay 16 in the input and output circuits of the main inverter 14 is energized through a contact 38 of a relay 40, and heater coil 50 of a thermal delay switch is energized through contact 46 of relay 40. The A.C. volts of the inverter energize relay 58 and move contact 60 down to keep relay 16 energized when, after a short time delay, thermal switch contact 64 moves down, and energizes coil 68 of relay 40. The consequent downward movement of switch 40 not only breaks the supply to relay 16 through contact 38, but also the supply to the heater of the thermal switch 50. Coil 69 remains energized, however, through contact 70, while engagement of contact 72 ensures that, if the main inverter fails, and contact 60 of the consequently de-energized relay 58 moves up, the relay 20 controlling the spare inverter is immediately energized. If the main inverter is faulty when switch 32 is closed, contact 60 remains in its upper position and relay 20 is energized when switch 40 moves down after the time delay determined by switch 50. A signal 22, operated by a relay 23, indicates inverter failure.