Abstract: In combination with an electrical appliance, an automatic warning circuit to warn a user of an electrical hazard wherein the warning circuit comprises a timing circuit responsive to turn-off of the electrical appliance for generating a triggering signal after lapse of a predetermined time period after turn-off thereby to energize an audible alarm. The timing circuit and alarm are useful for warning a user of the appliance of an electrical safety hazard brought out by the appliance being connected to a power line while not being used.

Abstract: Electrical systems, especially elongate heating systems, include means for monitoring circuit continuity and/or absence of ground faults. The systems comprise a switching device, e.g. a thermostat, as well as a circuit breaker. When the switching device is on, a relatively high current passes through the circuit and when it is off, little or no current passes through the circuit. In one embodiment, a small controlled residual current flows in the circuit even when the switching device is off, and a current-detecting device signals when a discontinuity causes the current to drop below the expected value for the residual current. In another embodiment, the switching device is placed so that the heater (or other electrical load) is at a positive potential with respect to ground even when the switching device is off, and a ground fault indicator is used to compare the currents in the two legs of the circuit and to signal when a ground fault causes the currents to differ.

Abstract: In a method and an apparatus for regulating the power which is supplied to a heating element (2) in a water heater (1), preferably a reservoir water heater containing water which is to be heated to a certain temperature, the power which is supplied to the heating element for heating the water, is regulated not only in dependence on the temperature of the water (15), but also in dependence on the temperature of the heating element (2, 4), so that the temperature of the element is kept below a predetermined critical value. The temperature of the heating element is measured directly and/or indirectly, and when the temperature of the element is below the critical value and the temperature of the water in the water heater is below the rated value, maximum power can be supplied to the heating element.

Abstract: A current shunt in the power supply to an electric furnace generates a signal voltage proportional to furnace current. A voltage rate comparator senses a high change rate of signal level corresponding to arcs occurring in the furnace and the comparator output pulse is fed to a preset counter. The counter is reset periodically. If a predetermined number of pulses are registered by the counter within a preset time interval, the counter output will de-energize an output relay which turns the power supply off and energizes a warning signal.

Abstract: Control signals are transmitted through a.c. mains supply lines to control operation of electrical equipment powered from the supply lines. A near short-circuit condition is introduced across the a.c. mains supply lines, for example, by firing a thyristor connected in series with a fuse across the supply lines, for the final portion of positive half cycles of the mains supply voltage, thus holding the voltage to a near zero value for this length of time. A receiver coupled to the mains supply lines includes a zero crossing detector circuit which responds to the near zero voltage conditions across the supply lines to perform a particular control operation on an associated appliance connected to the receiver. Different control operations may be effected by defining the control signals over a group of half cycles of the a.c.

Abstract: Temperature controlled electrical power supply apparatus for heating carpet-joining tape of the type having a conducting foil adapted to be heated by electric current to melt adhesive thereon includes first control circuitry for receiving A-C power supply voltage and a first adjustable resistor to provide an adjustable high current output. A switch is parallelly connected with the first normally open contacts of a first relay and actuated by the closure of a switch with second normally open contacts of that relay closed to enable the high current output. Second control circuitry includes a thermistor adapted to be connected in thermal contact with the foil such that the high current output is interrupted when the temperature of the foil reaches a preset temperature so as to maintain the foil temperature substantially constant. An SCR includes a gate circuit connected to the thermistor for controlling a second relay to interrupt the high current output.

Abstract: A thermostatic control for electric cables used on overhanging eaves of pitched roofs in northern climates, and in rain gutters and downspouts, comprises a high temperature-limit switch and a low temperature-limit switch connected in series circuit for controlling energization to a narrow temperature range extending from the freezing temperature of water to several degrees colder. Above-freezing temperatures will melt ice and snow without supplemental heating, and sufficiently colder temperatures will not be raised sufficiently by heat loss through a building roof to thaw ice and snow accumulation on the roof and provide run-off water to the unheated eave, rain gutter and downspout where freezing can occur and result in the formation of an ice dam which will block drainage of further run-off water and which may grow in size to cause water to back-up and seep under roofing shingles to leak through the roof.

Abstract: The present invention relates to a battery powered thermal garment that is provided with a battery recharging circuit that is designed to recharge a battery package associated with said thermal garment approximately 30-40 times as fast as conventional recharging devices. In addition, the recharging circuit of the present invention is provided with a separate and direct power source for energizing the heating elements within said garment independently of said battery package. With respect to the recharging circuit, a transformer is provided for stepping down a AC voltage source and the transformer includes a dual tap, one for providing the independent power source to the garment and the other providing a recharging current. The recharging current is rectified and then directed through a silicon control rectifier to the battery package for recharging.

Abstract: Two different types of circuits, the first a coil operation circuit and the second an operating circuit can be effectively used together in connection with an assembly such as a desoldering tool having a remotely located, associated structure for use in regulating when a vacuum is available at the tool in response to manipulation of the tool. The operating circuit employed utilizes a current control circuit capable of being actuated through the use of a switch on the tool to pass a full or a half wave AC current and a load such as a heating element located on the tool. The operating circuit also includes a detection circuit for determining whether a full or half wave current is being utilized to supply power to the load which is positioned within the associated structure. The coil operation circuit is located within this associated structure and includes a bidirectional solid state switch is series with a coil, another solid state switch in parallel with the coil, and the first noted switch.

Abstract: A power controller for controlling the intermittent supply of current to a load, such as a cooker hotplate, has a pivotally mounted snap switch controlled by a heated bimetal member which is heated in dependence upon the connected power. A compensating bimetal strip, for taking ambient temperature into account, is arranged on the snap switch and parallel thereto. A control cam acts on the free end of the compensating bimetal strip. The latter is shielded from the heat of the heated bimetal member.

Abstract: An automotive electric quick heat system utilizing a resistive heating element connected in series between the DC output terminal of a driven alternator and the voltage regulated terminal of the main storage battery. A shunting relay is controllable to bypass the resistive heating element when the conventional engine generated heat reaches a predetermined temperature. A first embodiment utilizes the automatic electric quick heat system in the carburetor air intake of an automotive engine. A second embodiment utilizes the automatic electric quick heat system for supplying heat to the passenger compartment following disconnect of the air carburetor intake quick heat.

Abstract: In an electronic control device for electric ranges having a plurality of individual heat settings to selectively energize a heating element of the range under the control of a digital input to produce switching pulses having different on-off ratios, each heat setting has an associated time controlled constant power period in the start-cooking or roasting range, and in the subsequent finish-cooking range there are produced switch-on and switch-off pulses having a constant time pattern at every heat setting, while the time duration of the constant power period and the duration of the switch-on pulses in the finish-cooking range are different from one heat setting to another.

Abstract: A heater roll in which a resistor-type heater mounted in the roll is controlled by use of a temperature sensing element also located in the roll. Electrical power, particularly AC power, is provided through slip rings and the set point for the temperature control is determined by a signal from a current source applied through the slip rings. The set point transmitter is designed to provide a constant current signal to the temperature regulator, irrespective of resistance variations which may be introduced by changes in the slip ring characteristics. As such, the temperature regulator maintains a predetermined temperature in the rotating roll, irrespective of slip-ring resistance variations.

Abstract: A device for controlling the temperature of the fixing means of direct-heating type in the electronic photographic copying machine wherein a desired temperature of a temperature detecting element in the fixing means is set to a value, at which a few sheets of copying papers can be fixed, and then changed to another value lower than the first one to copy more sheets of copying papers after the copying operation of a few sheets of copying papers is finished.

Abstract: A sensor, located to respond to the temperature of the cooking platform and having a positive temperature coefficient of resistance throughout a range of temperatures up to the maximum selected safe operating temperature of the platform, is connected to a thermal cycling control switch and provides an increasing resistance with an increasing platform temperature to effect a wattage limiting control of the heating element supplying heat to the platform.

Abstract: A power controller for controlling the intermittent supply of current to a load, such as a cooker hotplate, has a pivotally mounted snap switch controlled by a heated bimetal member which is heated in dependence upon the connected power. A compensating bimetal strip, for taking ambient temperature into account, is arranged on the snap switch and parallel thereto. A control cam acts on the free end of the compensating bimetal strip. The latter is shielded from the heat of the heated bimetal member.

Abstract: A power controller for controlling the intermittent supply of current to a load, such as a cooker hotplate, has a pivotally mounted snap switch controlled by a heated bimetal member which is heated in dependence upon the connected power. A compensating bimetal strip, for taking ambient temperature into account, is arranged on the snap switch and parallel thereto. A control cam acts on the free end of the compensating bimetal strip. The latter is shielded from the heat of the heated bimetal member.

Abstract: A power controller for controlling the intermittent supply of current to a load, such as a cooker hotplate, has a pivotally mounted snap switch controlled by a heated bimetal member which is heated in dependence upon the connected power. A compensating bimetal strip, for taking ambient temperature into account, is arranged on the snap switch and parallel thereto. A control cam acts on the free end of the compensating bimetal strip. The latter is shielded from the heat of the heated bimetal member.