Abstract: The present invention is a control system for controlling the temperature of the fusing system. This control system utilizes the knowledge of the heating characteristics of the fuser filament along with the knowledge that the human eye is most sensitive to temporal changes near the 8 Hz to 10 Hz rate as well as the concept of shape factors to control the rate at which power is applied to the filament to bring the fusing system up to operating temperature. From the study of the electrical characteristics of the heating element it is known that the heating element resistance in the fusing system under study exhibits a thermal time constant of 330 mS while heating. Also, from the summary of flicker regulations it is known that the best reduction in flicker is for the case in which a ramp voltage change is implemented with a ramp time of at least 1 second.

Abstract: A handheld power control device adapted to be connected to an external power supply for controlling the electric power applied to a heating coil positioned in a fusible area of a thermoplastic pipe joint for thermally fusing the joint. A housing having a cover with a front panel displays various parameters and operating options of the device, and has a plurality of manually operable membrane switches for selecting displayed options and activating the device, and indicating devices for displaying operating states of the device.

Abstract: A liquid-crystal display arrangement consisting of a liquid-crystal display, a light source constructed as a fluorescent lamp and a heat source which is thermally coupled to the fluorescent lamp. The heat source is formed as an essentially flat sheet on the side of the lamp opposite the display, with the heat source connected is series with a PTC type temperature sensor. In order to achieve a uniform and rapid establishment of the optimum operating temperature of the fluorescent lamp, the heat source is formed by a temperature-controlled foil-type heating element.

Abstract: A heating control apparatus for use in a heating system having heaters for heating at least one location and temperature sensors for measuring the temperature of each location is disclosed. The heating system is connected to an electricity supply having a tariff which varies with time. The heating control apparatus comprises a data receiving arrangement for receiving data on the tariff and weather prediction information. A selector is provided which is operable by a user to select the desired temperature for each location and a desired time and duration of the desired temperature. A controller includes a memory for storing information on the thermal characteristics of each location and the heaters and is responsive to the data, the measured temperature and the temperature selected by the user as well as the stored information to determine the times at which the heaters are to be energised. The controller then controls the heaters in order to achieve the desired temperature in each location.

Abstract: The temperature of each heating element among a plurality of heating elements is regulated by opening and closing a relay associated with each heating element in response to the monitored temperature of each heating element. The voltage across all of the relays is interrupted simultaneously at predetermined intervals, and each relay is opened or closed only when the voltage is interrupted. This permits the use of relays having lower current ratings and also extends relay life.

Abstract: Use of PTC circuit protection devices in motor vehicle wiring systems. The devices can replace some or all of the fuses conventionally used. Preferred devices contain PTC conductive polymers. Because the PTC devices can be reset without physical access to them, the wiring system can be arranged more efficiently and more economically. For example, the size of at least some of the wires of the harness can in many cases be reduced.

Abstract: A spa control circuit is provided for regulating a water circulation and heating system in a spa or hot tub or the like. The control circuit comprises a thermostat circuit and a high temperature limit circuit, both of which receive a temperature signal from a common temperature sensor. A safety circuit responds to sensor failure to prevent operation of the circulation/heating system. A latching relay ensures system reset in the same operational state following a power outage. An arc suppression circuit substantially prevents arc damage to relay contacts subjected to frequent opening and closing in response to on-off cycling of the thermostat circuit. In a preferred form, the control circuit components are mounted within a compact housing having a heat transfer member in heat exchange relation with circulating spa water, whereby the spa water is used to prevent overheating of the control circuit components.

Abstract: An electric power supply for a heater includes a heater, a battery electrically connected with the heater, a booster circuit electrically connected with the battery, a condenser disposed between the heater and the booster circuit and control element which controls a charge and a discharge of the condenser.

Abstract: A control unit for controlling the temperature of a domestic water supply, comprising a temperature sensor for inserting into a water tank so as to produce a sensor signal representative of actual water temperature in a region of the temperature sensor and an electrical immersion heater for inserting into the water tank and energized by a source of electrical power. A setting device is adjusted by a user for setting a desired water temperature and producing a corresponding set signal, and a controllable switch is connected between the source of electrical power and the electrical immersion heater, and is responsive to the sensor signal and to the set signal for closing if the actual water temperature is lower than the desired water temperature and for opening if the actual water temperature is greater than the desired water temperature.

Abstract: This Measuring Method of the electric power consumption of the Inverter Cooker enables automatic measurements of the electric power consumption for the keep-warm function, whether actual keep-warm temperature is set somewhat higher or lower, so that the productivity of the Cooker will be improved and judgement for defects of the keep-warm heaters made easier.

Abstract: Method for the storage and controlled supply of electric energy for discontinuous loads in steelworks and in particular for metal melting systems and rolling mills, the method comprising at least one main supply line (18) connected to a main supply source (11) of electric energy and a plurality of loads (12-13-14-114-20), whereby the level of maximum active power supplied by that main supply source (11) to the steelworks is limited by a sub-station (27) to a level "P.sub.0 " lower than the peaks of maximum absorption by those loads (12-13-14-114-20), the method comprising at least one accumulation line (16) connected in parallel to the main supply line (18) and supplying at least one storage assembly (17), which is connected to the loads (12-13-14-114-20) through a secondary supply line (19).

Abstract: A drying apparatus for use in a photosensitive material processing system, which is designed so that nonuniformity of drying in a direction intersecting a belt-shaped photosensitive material, e.g., a photographic negative film, photographic paper, etc., is eliminated, and the overall electric power capacity of the system is minimized. A plurality of electric current heaters (44.sub.1 and 44.sub.2) are disposed in parallel in a direction intersecting belt-shaped photosensitive materials (F.sub.1 and F.sub.2) transported, and each electric current heater is individually current-controlled to change the temperature distribution of the heated air, thereby compensating for the nonuniformity of drying of the belt-shaped photosensitive materials (F.sub.1 and F.sub.2) in the lateral direction, for example. The electric current heaters (44.sub.1 and 44.sub.2) are individually current-controlled by making the current input time different for each electric current heater.

Abstract: An electrical control scheme which permits operating power for a microwave oven and a second electrical appliance, such as a refrigerator, to be withdrawn from a single electrical outlet utilizes electrical contacts across which a voltage differential is generated when the oven is in operation and includes wiring connected between the second electrical appliance and the microwave oven. The included wiring conducts electrical power to the second electrical appliance from the power cord of the microwave oven, and the control system further includes a relay having a normally-closed switch.

Abstract: A heater for heating fluid is shown having a plurality of self-regulating electrical resistance heater elements 22 placed in electrically and thermally conductive relationship with heat transfer members 20, 120. The heat transfer members are each configured to form a plurality of fluid receiving channels so that when placed in a fluid stream heat generated by the heater elements will be dissipated to the fluid through the heat transfer members. Additionally, thermally conductive grease is used between the heater elements 22 and heat transfer member 20, 120 to better transfer the heat. The heater elements are arranged in groups with at least two heater elements in a group electrically connected in series and the groups electrically connected in parallel.

Abstract: A heat treatment system is fabricated from a loading section, a heat treatment section and a outlet section integrated with one another, and the heat treatment section comprises a transfer mechanism provided between the loading section and the outlet section for successively transferring silicon wafers, a heating unit provided along the transfer mechanism for heating the silicon wafers, and a cooling unit provided along the transfer mechanism and closer to the outlet section than the heating section for cooling the silicon wafers so that the silicon wafers are continuously treated with heat for annihilating thermal donors produced from oxygen during the growth of a silicon crystal without any handling by operators.

Abstract: A heat generator is formed to quickly raise the temperature of an object to be heated to a target level and then maintain the temperature of the object at the target level. The heat generator includes a high output heating element for heating the object to be heated, a temperature controller which is thermally coupled with the object and connected in series with the high output heating element for deenergizing the high output heating element when the temperature of the object exceeds the target level while energizing the high output heating element when the temperature of the object is reduced from the target level by a prescribed value, and a positive temperature coefficient thermistor which is thermally coupled with the object and connected in parallel with the high output heating element and the temperature controller, the thermistor having a Curie point set so as to produce an output capable of maintaining the object at the target temperature even when the high output heating element is deenergized.

Abstract: This invention relates to the control of the temperature of heated fluid flow through a so-called single pass electrical heater. Specifically, a controller and accompanying flow circuit including a flow through single pass electrical heater is disclosed which provides for heating of water upon initiation of flow. A two stage control protocol is utilized for routing current under precise control to the heater element. In the first protocol utilized at start up to a control temperature limit slightly below the temperature set point, phase angle of current turn on with zero crossing current turn off control a 220 volt current to the single pass heater element. Once the control temperature is achieved, incremental adjustment of phase angle thereafter occurs with rapid asymptotical approach of the output temperature of the flowing water to a preselected temperature "set point" occurs.

Abstract: A self-regulating heater including a resistance element for converting electrical power to thermal energy and a power supply includes circuitry for controlling its output during heat up along a path bounded by two preferred paths:1) a path defined by constant voltage with a cross-over to constant current for a NTCR heater element when the power output reaches a maximum or a path defined by constant current with a cross-over to constant voltage for a PTCR heater element when the power output reaches a maximum; and2) a path defined by constant power with a cross-over to maximum current for a NTCR heater element or to constant voltage for a PTCR heater element when the power supply reaches maximum current or maximum voltage output respectively. When the heater element reaches the set control temperature, the power supply then maintains power equilibrium with the thermal load through controlling its output according to resistance control, i.e.

Abstract: In an apparatus for detecting turn-on state of plural heaters including an electric power source for supplying electric power to the plural heaters, a controller controls the electric power source to be turned on and off so that each of the plural heaters is turned on and off in a predetermined manner, and a current sensor measures the total current supplied from the electric power source to the plural heaters. Then, a comparator compares the total current measured by the current sensor with plural reference values different from each other and outputting signals for representing comparison results thereof, and a judging circuit judges turn-on or off state of each of the plural heaters based on the signals outputted from the comparators.

Abstract: Plural electrical loads supplied with power from a single source are monitored to detect defective loads. Each load is periodically individually energized and current delivered by the source is measured. Measured current for each load is compared with limit values to detect abnormal values. To overcome consequences of supply voltage fluctuations, supply voltage is also measured and admittance of each load is determined from measured current and measured voltage. The admittance value thus determined for each load is compared with limit values to detect abnormal values. Load monitoring of loads energized according to a control algorithm proceeds by periodic momentary suspension of energization according to the control algorithm and energization of selected individual loads.

Abstract: An electrical system for supplying power to an electrical resistive heater that heats the catalyst of a catalytic converter. The electrical system includes an alternating current generator that has an output winding and a field winding that is carried by the rotor of the generator. The rotor is driven by an engine on a motor vehicle. The motor vehicle loads, including a storage battery are supplied with current by a first bridge rectifier that is connected to the output winding of the generator. The resistive catalyst heater is supplied with current by a circuit that includes a step-up transformer connected between the output winding of the generator and a second bridge rectifier that feeds the heater. The system can be operated in a high power mode for supplying a higher level of power to the heater.

Abstract: A circuit for controlling the energizing of heating elements (13), including transistors (12) for controlling the energizing of the respective heating elements, energizing start time counter circuits (22) for determining a delay time until the energizing of the respective transistors (12) is started, and energizing time counter circuits (23) for determining energizing time. Data are written to the respective counter circuits from the outside via a group of multi-bit, multi-stage latch circuits and a counter clock signal (8). The energizing start time counter circuits (22) are collectively and simultaneously caused to perform a count (subtraction) operation. Then, the energizing time counter circuit (23) is made to start a count operation at a point in time when each of the energizing start time counter circuits (22) holds a value of 0, and the transistors (12) start to energize each heating element (13).

Abstract: A steam generator for domestic and industrial use, of the type which has a boiler (5) provided with a resistance heater element (17) and a steam and energy take-off unit (10) for supplying steam and electrical power to an external user item, such as a smoothing iron. At least a first solenoid valve (7) and a second solenoid valve (8) are connected between the boiler (5) and the take-off unit (10) to give rise to at least three separate levels of output steam rate. An electronic controller is coupled to the resistance heater element (17), steam and electrical power take-off unit (10), the power source and the solenoid valves (7,8) for automatically and proportionally exchanging electrical power applied to the resistance heater element (17) with electrical power applied to the external user item, thereby effectively exchanging the amount of steam available for use by, and the electrical power applied to, the external user item.

Abstract: A cooking appliance adapted for energization by a standard domestic household power supply employs a power control arrangement which accommodates electric resistive heating units designed for operation at a maximum RMS voltage level less than the RMS voltage level of the output power signal of the domestic power supply. The power control system couples power pulses from the external power supply to the heating unit at one of a plurality of available pulse repetition rates, each repetition rate establishing a corresponding RMS voltage level for application of power to the heating unit. The repetition rate associated with the maximum user selectable power setting for the appliance is effective to apply an RMS voltage level to the heating unit which corresponds to the voltage level for which the heating unit was designed.

Abstract: A system for heating water using solar energy comprises a photovoltaic array, a water heater comprising a variable resistive load, and a controller for varying either the load characteristics of the resistive load or the power generating characteristics of the photovoltaic array, or both, to ensure maximum power transfer efficiency.

Abstract: A method and apparatus for automatically and dynamically tuning individual heater segments of a multi-zone furnace which allows simultaneous minimization of temperature gradients within the furnace and prevention of premature aging and failure of the segments by controlling the relative temperatures thereof and equalization of the contributions of the segments to the heating of the furnace. Furnace and heater temperatures are monitored and furnace temperatures are used to develop set point biases for automatic control of heater segment temperatures. Some segments are also controlled as a function of power applied to other segments. Temperatures sensed within the furnace are combined such as by averaging to effectively provide virtual sensors in locations where sensors cannot otherwise be practically provided.

Abstract: An electrically operable heating system which comprises a plurality of heating units has one or more control units for controlling the operation of each heating unit. Each control unit operates on the basis of two input signals (F) and (P). One (F) represents the maximum proportion of the power of the associated heating unit or units which can be made available at any time and the other (P) represents the fraction of that proportion required at a particular time. Also disclosed is a system in the switching of heater units is carried out in a random manner.

Abstract: In a capillary rheometer including: a furnace comprising a plurality of furnace zones and having a sample bore with a capillary connected to the lower end thereof; a plurality of heaters for heating the furnace zones thereby to heat a sample in the sample bore; and a plunger for extruding the heated sample through the capillary; a plurality of temperature sensors are provided for detecting the temperatures of the furnace zones, and the temperature characteristics of the furnace zones related to the temperature of the inner wall of the sample bore are obtained and stored in a controller.

Abstract: A heater control apparatus for use with a plurality of printers each having a heater, comprises a detection part for detecting occurrence of zero crossing of a voltage signal supplied from a power supply and for supplying a zero cross signal each time the zero crossing is detected, a signal part for detecting an ON state of a request signal, the request signal being turned ON when a heater of any of the plurality of printers is currently turned ON, a first control part for determining a delay time in accordance with a predetermined device number setting value such that a timing with which a heat-on signal is supplied to a heater of a subject printer lags by the determined delay time behind a timing with which the zero cross signal is supplied by the detection part, and a second control part for supplying a heat-on signal to the heater of the subject heater at a timing defined by the determined delay time only when the request signal is turned OFF, thereby preventing two or more heaters from being turned ON si

Abstract: An electrical logic circuit for incorporation in the common power supply system of an appliance including a plurality of electrical components which have intermittent power requirements comprises a system for designating the components as dominant and subsidiary components and circuitry to direct power to the dominant component preferentially and to the or a subsidiary component only in dependence on the instantaneous power requirement of the or a more dominant component. The logic circuit may include a standby facility to direct power selectively to the subsidiary component. The invention may be applied to an ironing system including a heatable iron as the dominant component and a heatable board as the subsidiary component.

Abstract: An apparatus ensures that a controller memory is programmed to store safety critical information corresponding to a heating system in which it is installed. The heating system has a controller and a controller memory which controls the heating system based on input parameters provided to the controller and based on safety critical information stored in the controller memory. A program signal is generated when the controller memory is electrically disconnected from the heating system indicating that the controller memory must be programmed to include safety critical information. Operation of the heating system is inhibited in response to the program signal.

Abstract: A process and device for controlling heating of a furnace by means of electrical resistors using switching devices, particularly thyristors, associated with the electrical resistors, and whose operation is to be controlled. The switching devices are controlled in syncopated mode by an industrial computer, a programmable industrial robot or equivalent which performs a set of functions which make it possible to compute the power to be dissipated in the resistors, and control directly the switching devices so as to dissipate the previously coputed power. The invention applies particularly to controlling industrial furnaces and more particularly of glassmaking furnaces, particularly furnaces for heating of glass for the tempering and/or bending of the glass.

Abstract: An electric sauna heater comprising at least one electric resistor (10) for heating the sauna room and a steamer (1 to 9) for generating steam in the sauna room, the steamer comprising an evaporating space (4) and at least one electric resistor (9) for evaporating the water contained in the evaporating space (4). To achieve efficient evaporation without applying high capacities at the evaporating resistor, the sauna heater comprises a thermostat (5) which disconnects power from the water evaporating resistor (9) when opening the supply of water to the evaporating space (4) and connects power to the evaporating resistor (9) when closing the supply of water to the evaporating space (4).

Abstract: Disclosed is a device for and a method of applying output voltage from a power generator to a heating resistor in a motor vehicle. During the standstill condition of the vehicle the heating resistor is connected directly to the generator and a power supply network connected parallel to the terminals of a battery, is disconnected from the generator. The output voltage of the generator is regulated to increased values to achieve a higher efficiency in the heating resistor. During the travel of the motor vehicle, the heating resistor is connected in series with the power supply network and a regulated voltage from the power generator is applied across the series connection. The output voltage is regulated such that a nominal voltage is maintained at the power supply network. The switchover between the standstill and running operational conditions is provided by two switching devices which are controlled by a control device in dependency on operational conditions of the motor vehicle.

Abstract: The invention relates to a method of controlling the supply of electric power to an electric sauna heater, the sauna heater being divided into two portions to be heated separately: a stone space (1) and an air duct (2) each being provided with one or more heating elements (1A1-1A3, 1B1-1B3, 2A1-2A3, 2B1-2B3) to heat the heat-storing material placed in the stone space (1) and the air contained in the sauna room, respectively. In the invention, to achieve good operating properties in this kind of sauna heater both with respect to the heating of the stone space and the air space of the sauna room without increasing the rated wattage of the sauna heater to an unreasonably high value, one or some of the heating elements are disconnected or connected to operate at partial power, whereby the power demand of the sauna heater is always smaller than the total power of the heating elements (1A1-1A3, 1B1-1B3, 2A1-2A 3, 2B1-2B3).

Abstract: The present invention relates to controllable electric heaters, in particular heaters employing tungsten halogen lamps and suitable for use in cookers of the type having a ceramic hob below which are placed the heaters.It is an object of the present invention to provide a controllable electric heater employing two tungsten halogen lamps and other components of an inexpensive nature and which allows six different power settings to be obtained.

Abstract: A temperature control method is provided which is capable of carrying out a more efficient temperature control through an impartial starting of a plurality of temperature control objects such as the respective heating elements in the liquid tank portion and the drying portion of a developing device for photosensitive material. According to the method of the present invention, a required actuating time is allocated for each of the heating elements within one cycle of a predetermined length of time. As a result, it is possible to supply the required energy for each of the heating elements in a well-balanced manner.

Abstract: In a prior art thermal printing method, the heating elements of a thermal printing head are driven in such fashion that the temperature of each and every individual heating element is first measured individually and successively before this heating element is charged with a current pulse whose intensity of current is dimensioned dependent on the measured temperature. In order to increase the printing speed, the temperatures of all heating elements (R1 . . . Rn) are first successively measured in the novel method fo the present invention in every drive cycle and are extrapolated to isochronic cooling temperature values dependent on the cooling characteristic of the heating elements (R1 . . . Rn). The heating elements (R1 . . . Rn) are then charged with current pulses whose pulse durations are individually dimensioned for every heating element (R1 . . . Rn) dependent on the cooling temperature value calculated for this heating element (R1 . . . Rn).

Abstract: A low cost system for permitting the remote load management control of electrical residential room heating units that is compatible with existing heating systems of the type wherein each room heating element is controlled by a manually settable line voltage thermostat responsive to ambient room temperature. Included in the system is a normally closed low voltage operable thermal relay included immediately downstream of a resident circuit breaker and in the power transmission line for each room heating element and an associated single user programmable set back thermostat for shifting said thermal relays from normally closed to open position in response to residential dictated parameters of operation capable of also being operated in response to a remotely generated signal from a load management control center.

Abstract: An improved power control system for a household cooking appliance of the type having a glass ceramic cooking surface and at least one radiant heating unit disposed beneath the cooking surface operable at a plurality of user selectable power settings. At least one of the power settings has associated with it predetermined maximum and minimum reference temperatures defining a temperature band representative of the steady state temperature range for the glass ceramic support surface proximate the heating unit when heating normal loads at that power setting.

Abstract: A power control system for operating a heating element in a cooking appliance in response to the selection of one of a plurality of user selectable power settings. Approximate heating element temperature information is provided by a heater energy counter. Each power setting has associated with it a corresponding steady state power level and a corresponding predetermined steady state energy count. The steady state energy count is approximately proportional to the steady state operating temperature of the heating element when operated at its corresponding steady state power level. The energy counter is selectively incremented and decremented to approximately track the heating element temperature when the count is respectively less than or greater than the steady state count for the applied power level. At least certain ones of the power settings have corresponding minimum threshold counts less than the steady state counts and maximum threshold counts greater than the steady state counts.

Abstract: Method and device to supply, from a source of alternating voltage (5a or 5b), a thermal printing head (3) comprising a number of heater units (3a, 3b).The device comprises a means (6a to 6d) of obtaining a rectified voltage, a means (8) of detecting the points when the alternating voltage or the rectified voltage change to zero and to produce a detection signal, a means (9) of synchronizing, with this detection signal, the heating of particular heater units and a means (7a, 7b) to absorb current.

Abstract: A heater backed with a ceramic substrate having a ceramic substrate as a base plate and heating element formed thereon, which comprises a conductor for retaining ionized elements, said conductor branching from a terminal lead portion of the minus side connected to the heater element under an applied electric current and extending at the back side of the base plate, along the heating element pattern at least partly thereof. A protecting layer may be provided on the surface of said conductor. The conductor is connected with the lead portion through a conducting through hole.

Abstract: An electric curling iron operative to provide uniform heating at both domestic (120 v) and foreign (240 v) voltages includes first and second rope-type electric heaters disposed side by side in the heatable barrel of the curling iron. The heaters are of the same configuration, coextensive in length with each other and the length of the barrel and are separated from each other by a sheet of electrical insulating material dividing the barrel longitudinally into two compartments each containing one of the heaters. A double throw switch on the curling iron enables energization of the first heater alone at the domestic voltage and both heaters in series at the foreign voltage, the relative resistances of the heaters being selected to produce the same output wattage whether the first heater alone or both heaters are energized.

Abstract: A microcomputer control system for a furnace is disclosed which provides accurate control of the temperature of the furnace such that the temperature can be quickly increased to a predetermined desired temperature without overshooting the desired temperature. The control system determines the tuning constants of the furnace as a function of the system's response to a predetermined input and, thereafter, uses the determined tuning constants to accurately control the temperature of the furnace. The control system employs a novel method for increasing the temperature of a furnace wherein full power is applied to the furnace heat source until the microcomputer makes the determination, based upon the furnace tuning constants, that power supplied to the furnace must be reduced to prevent the temperature of the furnace from overshooting the desired temperature.

Abstract: A control system for a thermal print head includes means for regulating the firing of the print elements with the proper pulse width to compensate for increasing substrate temperature. The control circuit is divided into two separate circuits--the driving circuit for turning the print elements on and off, and the decision-making circuit which executes the substrate temperature coding and control codes and sends control signals to the driving circuit. Three types of temperature compensation are utilized in the control program. A tailored pulse width is used for each bank of the print elements to compensate for various element resistances. As the print head shuttles across the record medium, the pulse width is reduced for each horizontal dot position. The pulse width also is reduced for each line printed in the format. The system may be used for either direct thermal or thermal transfer printing with both full and half dot spacing and single or double width characters.

Abstract: A controller for controlling an electrode boiler steam humidifier, of the type operable from a source of polyphase alternating current, is provided. A plurality of current loop transformers, coupled to the boiler electrodes, sense the individual currents drawn in each phase of the polyphase alternating current. A plurality of full-wave bridge rectifiers individually couple the secondaries of the current lube transformers to the input of a voltage amplifier such that the output of the amplifier is indicative of the highest of the currents sensed in each phase of the boiler electrode current. When the output of the voltage amplifier exceeds a predetermined threshold, a control effect is produced such that operation of the humidifier is controlled in accordance with the highest of the individual phase currents drawn through each of the boiler electrodes.

Abstract: The bushing balance controller is an electronic device which measures the voltage drop across each segment of a multiple segment glass fiber forming bushing and measures the current flow in the bushing. The device uses these measurements to produce error signals proportional to the difference in the set point temperature and the instantaneous temperature of each segment of the bushing. The device diverts current from each segment of the bushing whose error signal is greater than the average of the error signals for all segments of the bushing. The device also sums all error signals and passes this signal to a bushing controller which adds current to the bushing when the sum of the error signals falls below a preset value.

Abstract: A unit for converting a fossil fuel burning furnace into an electrical furnace for utilization of electrical energy for heating, except under those periods of high energy usage during which the cost of electrical power is high, or during periods when extreme loads exist upon the electrical supply. During such times, a control system is provided to automatically revert the furnace to a fossil fuel burning operation. The unit includes an electrical heating device including a plurality of electrical heating elements arranged in a vertically staggered array for insertion into the ductwork of the fossil fuel burning forced air furnace, such that the elements are in close association to the plenum of the furnace and such that the fan or blower of the furnace provides air flow past such elements.

Abstract: A step controller for a water heater includes a plurality of individual electrical elements to maintain a predetermined minimum temperature in accordance with a sensed temperature signal and a preset desired temperature signal in combination with a dead band signal. The heating elements are turned "on" and "off" in a random sequence whenever a change is required, and in accordance with a binomial distribution so as to substantially equalize the operating period of the heating elements. The controller includes a microprocessor unit to periodically sense the signals of a sensor and a preset potentiometer, and also operates to store the on-off status of the heating elements, each of which is assigned a binary load indentifying number. The microprocessor includes a psuedo-random binary number generator for generating the load identifying numbers.