Abstract: A temperature control system including an enclosure defining a zone to be temperature controlled, a primary temperature conditioner for controlling ambient temperature within the zone, a temperature sensing mechanism for producing temperature signals dependent on localized temperature within the zone, a controller for controlling the primary temperature conditioner in response to the temperature signal, an error detector for monitoring the temperature signal and producing error signals in response to predetermined abnormal output conditions thereof, an auxiliary temperature conditioner disposed in close heat transfer relationship with the sensing mechanism and selectively energizable during test periods to substantially alter the localized temperatures sensed by the sensing mechanism without substantially changing the ambient temperature within the zone, and a fault detector for producing fault signals in response to given defective output conditions of the temperature signal during the test periods.

Abstract: A ground leakage current interrupter circuit including a transformer having a pair of balanced differential primary windings and a secondary winding, a fault detector for monitoring the output of the secondary winding and producing a fault signal in response to increases in the level of the secondary winding output that occur at greater than a predetermined rate, and a circuit interrupter responsive to the fault signal produced by the fault detector. Preferably, the fault detector includes a level detector for producing the fault signal in response to secondary winding output levels greater than a reference signal level, and a reference supply that varies the reference signal level in dependence upon the level of the secondary winding output so as to prevent production of a fault signal in response to increases in the secondary winding output that occur at less than the predetermined rate.