establishment of the rules of energiegesamtleistung, depending on a zustandsfuehler, using at least two controlled sources

摘要

1,194,565. Automatic temperature control systems. HONEYWELL Inc. Aug.23, 1967 [Oct. 5, 1966], No.38916/67. Heading G3R. An air heater 14 is variably energized under the control of a sensor 63 and additional heaters 15, 20 are switched into circuit successively as the heating requirement increases, the heater 14 current being decreased when another heater 15 or 20 is switched in. The heater 14 is controlled by a relay 22 whose mark space ratio is varied by a transistor 52 fed from a relaxation oscillator 55 through transistors 54, 53, the bias on the latter being varied with measured temperature by a transistor 61 controlled by a temperature sensitive resistor arrangement 63, transistor 61 being stabilized against ambient temperature variations. When heater 14 is energized at a high level, a circuit 72 is energized which closes switches 24, 40, the latter modifying the potential on a line 64 which reduces the output of heater 14 to a low level. Similarly when the heater 14 is again fully energized switches 25, 41 are closed, further modifying the potential on line 64. The heaters 14, 15, 20 may have unequal ratings, i.e. the heater 14 may have a higher rating e.g. 7À5 K W compared with 5À0 UW for heaters 15, 20.