Matches 101 - 150 out of 180 < 1 2 3 4 >
Match Document Document Title
4540866 Induction heating apparatus  
An induction heating apparatus which is adapted to stop heating when a load is abnormal and adjust the time period of turning on a switching element of an inverter circuit including an induction...
4535212 Apparatus and method of hardening valve seats  
A method and apparatus for inductively heating valve seats wherein an inductor is driven to a predetermined magnetic coupling with the valve seat under the control a range detecting transceiver unit.
4511956 Power inverter using separate starting inverter  
A method and apparatus are provided for an improved power inverter circuit, including a separate starting inverter having an A.C. output applied across a load prior to energizing the main inverter,...
4511781 Induction cook-top system and control  
An induction heating system (40) is provided and includes a plurality of induction heating coils (118). Touch control pads (50, 52, 70, 72) are provided together with circuitry (80) for generating...
4507722 Method and apparatus for controlling the power factor of a resonant inverter  
A method and apparatus for controlling the frequency of a power inverter for converting D.C. current into A.C. current having a frequency controlled by gating signals, which apparatus and method...
4506131 Multiple zone induction coil power control apparatus and method  
A plurality of zones of an induction heating coil are individually controlled by varying the current through one or more zones of the coil to obtain a desired temperature profile in a workpiece....
4501942 Method and apparatus for uniform induction heating of an elongated workpiece  
Method and apparatus for uniformly heating a workpiece such as a sucker rod or the like having a uniform cross-section over a major portion of its length and an enlargement adjacent each end...
4492840 Apparatus for inductively heating metallic medical and dental tools  
An induction heating process and apparatus for flameless heating of metallic dental laboratory tools, medical instruments, and the like. The induction heating coil is energized by placement of...
4482793 Apparatus for simultaneously heating a plurality of elongated workpieces  
A device for inductively heating simultaneously and alike a plurality of identical elongated workpieces each having at least two axially spaced portions, to produce identical predetermined heat...
4471196 Solid state radio frequency power generator  
A solid state radio frequency high power generator for induction heating applications uses MOSFET devices controlled at radio frequency by a current loop which is automatically corrected against...
4467165 Induction heating apparatus  
In an induction heating apparatus wherein heat is generated in a magnetic material by eddy currents produced by high frequency magnetic field of a heating coil (32), zero crossing point of the...
4464553 Induction heating apparatus with an override circuit  
An induction heating apparatus for cooking includes an induction heating coil which generates a high frequency time-varying magnetic field used to heat a metal object; a high frequency inverting...
4456807 Induction heating cooking appliance  
An induction heating type cooking appliance is adapted to heat a pan by induction heating. An input unit includes touch control keys and has a timer function so that the power supply is turned on...
4447691 Circuit for detecting a utensil load placed asymmetrically relative to an induction heating coil  
A plurality of magnetic field sensors are mounted adjacent the periphery of an induction heating coil of flat, spiral configuration which is energized by ultrasonic frequency energy to generate a...
4430542 Electromagnetic cooking apparatus  
The disclosure is directed to an improved electromagnetic cooking apparatus which is so arranged that the maximum voltage to be impressed to a switching transistor employed in it may be lowered to...
4429205 Induction heating apparatus  
An induction heating apparatus which includes an induction coil with an associated load and a resonant inverter circuit coupled to a DC power supply for energizing the heating coil. The inverter...
4425489 Electromagnetic heating system for calender rolls or the like  
A calender roll whose shell consists of ferromagnetic material is heated by several groups of electromagnets which are mounted within the shell on a stationary carrier and whose pole shoes are...
4396818 Thyristor off-time controlled induction heating apparatus by differentiated thyristor anode potential  
An induction heating apparatus including a thyristor adapted to receive power from a power source, a gating control circuit for generating gating pulses for application to the gating control...
4356371 Small load detection by comparison between input and output parameters of an induction heat cooking apparatus  
An induction heat cooking apparatus includes an inverter which generates ultrasonic frequency energy for heating a magnetic load by induction, and a small load detection circuit. The detection...
4352000 Induction heating cooking apparatus  
An induction heating cooking apparatus comprises a self-controlled inverter which comprises a series connection of an induction coil and a switching element, a resonance capacitor connected in...
4334135 Utensil location sensor for induction surface units  
A utensil detection arrangement for an induction heating apparatus which provides a signal indicative of an off-center position of a cooking utensil supported on a cooking surface which overlies an...
4327268 Current control system for an induction heating apparatus  
Coil current loading the induction coils of an induction heating apparatus is directly sensed at the input from the tank circuit and the derived feedback current signal is used to control the power...
4320273 Apparatus for heating an electrically conductive cooking utensil by magnetic induction  
An induction heating apparatus comprising a static power converter operative to produce high-frequency power from low-frequency power and a heating unit to produce a time-varying magnetic field in...
4319109 Centered utensil sensor for induction surface units  
A sensor arrangement for an induction heating apparatus which monitors the position of a cooking utensil on a work surface and disables an inverter circuit powering a work coil if the utensil is...
4317975 Induction heating apparatus with means for detecting zero crossing point of high-frequency oscillation to determine triggering time  
Induction heating apparatus using gate-controlled switching devices includes a zero crossing point detector for detecting the occurrence of each zero crossing point of high frequency energization...
4317979 High current high frequency current transformer  
In an induction heating apparatus, direct sensing of the high frequency high power current flowing in the tank circuit to load the induction coils, is obtained with a coil current measuring...
4309586 High frequency induction heating circuit  
A high frequency induction heating circuit for heating a plurality of articles where the heating circuit has a semiconductor oscillation circuit which includes a series resonance circuit having a...
4289946 Electromagnetic casting apparatus  
An apparatus for casting metals wherein the molten metal is contained and formed into a desired shape by the application of an electromagnetic field. A control system is utilized to minimize...
4280038 Method and apparatus for inducting heating and melting furnaces to obtain constant power  
A method and apparatus for induction heating or melting furnaces of varying conductance, comprising controlled adjustment of the power factor angle in response to variations in load conductance to...
4210792 Induction heating apparatus with load detecting and control circuit  
The induction heating apparatus comprises a DC source, a series oscillation circuit including a heating coil and a capacitor connected across the DC source, a diode having an opposite polarity with...
4191188 Variable crest factor high frequency generator apparatus  
A high frequency power oscillator is keyed on and off to provide high frequency signal bursts under the control of a pair of timers whose duty cycles are simultaneously and proportionally adjusted...
4177494 Circuit arrangement for producing an open magnetic field  
A magnetic field for coupling to a load is produced by means of apparatus having first and second amplifiers operating in phase opposition and connected to a first oscillating circuit for...
4151387 Metal base cookware induction heating apparatus having improved power control circuit for insuring safe operation  
A metal based cookware induction heating apparatus having an improved power supply and control circuit comprised of a chopper inverter including a gate controlled power thyristor coupled to and...
4147910 Power adjustment with variable frequency and duty-cycle control for induction heating apparatus  
In an induction heating cooking apparatus, the frequency of electromagnetic energy is varied in response to a desired power setting level within an allowable range and the duty cycle of the energy...
4129767 Induction heating apparatus having timing means responsive to temporary removal of cooking implement  
A plurality of switches each is provided in the vicinity of each of a plurality of heater coils of an induction heating apparatus, and responsive to removel of a cooking implement from a...
4112287 Central oscillator for induction range using triac burner controls  
An apparatus for inductively heating cooking utensils comprising four induction cooking coils excited by a central power oscillator providing an alternating sinusoidal excitation voltage at about...
4095076 Protective device for induction heating apparatus  
A protective device for induction heating apparatus is disclosed. The device includes an excitor supplied with operating voltage for induction-heating a heating element and a detecting device for...
4085300 Frequency controlled induction cooking apparatus  
The invention relates to induction heating for cooking. Solid state reciprocal power switches are used to excite a resonant power output circuit including an induction coil to be inductively...
4074101 Induction heating apparatus using a pair of inversely parallel connected gate-controlled switching devices  
An induction heating apparatus comprising a pair of inversely parallel-connected gate-controlled switching devices connected to an alternating current source, a resonant circuit including an...
4016390 Induction heating apparatus with protective circuit arrangement  
An induction heating apparatus is provided with protective circuit arrangements which ensure against surge currents caused by inappropriately timed gating-on of a gate controlled rectifier or by...
4016392 Pan detector for induction heating apparatus  
Electromagnetic coupling between a pan or utensil load to be heated by magnetic induction and a source of high frequency magnetic flux is sensed by detecting a current which is indicative of the...
4013859 Induction cooking unit having cooking load sensing device and essentially zero stand-by power loss  
An induction heating unit is provided having an essentially zero stand-by power requirement and comprised by a high power solid-state inverter for supplying relatively high frequency excitation...
4010342 Induction cooking appliance having improved protection circuits  
An induction cooking appliance for heating a metallic utensil by means of an ultrasonic frequency magnetic field. The appliance includes a smooth, substantially non-metallic cooktop for supporting...
4009430 Antiparallel commutated inverter  
A control circuit for regulating power to a resonant load from a dc source including switching devices, magnetic means and antiparallel means for increasing the reverse voltage on the switching...
3919621 Control system for inverter circuits  
A control system suitable for rendering an inverter circuit nonoperative in response to an undesirable load condition. In an SCR inverter circuit during the portion of the anode voltage cycle, when...
3889090 Induction heat cooking apparatus  
There is disclosed cooking apparatus for heating a cooking utensil by magnetic induction from the work coil in a series resonant circuit driven by an oscillator operating at and tracking with the...
3886342 Induction cooking unit having all pan safe operation, wide range power control and low start-up and shut-down transients  
An induction heating unit including inverter circuit means comprised by a gate controlled thyristor and commutation circuit coupled together in circuit relationship and excited from a set of power...
3882370 Control of power converters having a parallel resonant commutation circuit  
In a variable operating frequency inverter or other converter with a parallel resonant commutation circuit, the frequency changes with the load to control the reactive power available for...
3823297 LOAD CONTROLLED INDUCTION HEATING  
An induction heating apparatus employing a series tuned, resonant circuit including a work coil adapted to be coupled to a load to be heated in a parallel, tuned, resonant tank circuit, a current...
3806690 CASE HARDENING ARRANGEMENT UTILIZING HIGH Q TUNED CIRCUIT  
Heating pulses are applied to body to be case hardened through a heating inductor coupled to a high Q tuned circuit through a low resistance, low inductance coupling loop. Tuned circuit is pulsed...
Matches 101 - 150 out of 180 < 1 2 3 4 >