Provided are systems that includes an a induction heating circuit and at least one processor programmed or configured to generate each line of a plurality of lines, where each line comprises a graphical representation of phase value versus frequency of a signal with which the induction heating circuit is driven, determine a line of the plurality of lines that has a maximum slope, determine an average frequency of the line having the maximum slope, determine a phase value corresponding to the average frequency of the line having the maximum slope, determine a time delay, determine a self-resonant frequency (SRF) value of the induction heating circuit based on the time delay, and determine a characteristic of the induction heating circuit based on the resonant frequency value. Methods and computer program products are also disclosed.

Provided are systems that includes an a induction heating circuit and at least one processor programmed or configured to generate each line of a plurality of lines, where each line comprises a graphical representation of phase value versus frequency of a signal with which the induction heating circuit is driven, determine a line of the plurality of lines that has a maximum slope, determine an average frequency of the line having the maximum slope, determine a phase value corresponding to the average frequency of the line having the maximum slope, determine a time delay, determine a self-resonant frequency (SRF) value of the induction heating circuit based on the time delay, and determine a characteristic of the induction heating circuit based on the resonant frequency value. Methods and computer program products are also disclosed.

The invention relates to a method and a heating device (1c) for inductively heating a stator (2) or armature (3) of an electric machine, in particular before and during trickle impregnation thereof. In addition, the invention relates to an impregnating device (50) in which this heating device (1c) is integrated. According to the invention, it is provided that the heating takes place inductively by electromagnetic fields of different frequencies. For this purpose, it is provided in the case of the heating device (1c) that it has at least one electromagnetic inductor (18, 21, 24) which is disposed coaxially or axially parallel with respect to the longitudinal axis (7) of the stator (2) or armature (3) and which inductively heats said stator or armature, and that the at least one inductor (18, 21, 24) is designed to generate at least two electromagnetic fields of different frequencies.

The invention relates to a method and a heating device (1c) for inductively heating a stator (2) or armature (3) of an electric machine, in particular before and during trickle impregnation thereof. In addition, the invention relates to an impregnating device (50) in which this heating device (1c) is integrated. According to the invention, it is provided that the heating takes place inductively by electromagnetic fields of different frequencies. For this purpose, it is provided in the case of the heating device (1c) that it has at least one electromagnetic inductor (18, 21, 24) which is disposed coaxially or axially parallel with respect to the longitudinal axis (7) of the stator (2) or armature (3) and which inductively heats said stator or armature, and that the at least one inductor (18, 21, 24) is designed to generate at least two electromagnetic fields of different frequencies.

A controller is connected to at least one transistor of the transistor driving circuit and connected to the at least one current sensing element to detect the current through the induction heating coil and in response to the current through the at least one current sensing coil exceeding a limit level sending a control signal to the at least one transistor of the transistor driving circuit to temporarily turn off the at least one transistor.

A controller is connected to at least one transistor of the transistor driving circuit and connected to the at least one current sensing element to detect the current through the induction heating coil and in response to the current through the at least one current sensing coil exceeding a limit level sending a control signal to the at least one transistor of the transistor driving circuit to temporarily turn off the at least one transistor.

The present invention intends to run one induction heating apparatus using a three-phase AC power supply without use of a Scott connection transformer while preventing an occurrence of a phase where no current flows. An induction heating system uses the three-phase AC power supply to run the induction heating apparatus including an induction heating coil, and has an intermediate apparatus including a coil that is wound on an iron core with an even number of turns, forming a closed magnetic circuit. Additionally, a winding start point of the induction heating coil is connected to the U phase of the three-phase AC power supply and a winding end point of the same is connected to a midpoint of the intermediate coil. The winding start point and end point of the intermediate coil are connected to the V and W phases of the three-phase AC power supply, respectively.

The present invention intends to run one induction heating apparatus using a three-phase AC power supply without use of a Scott connection transformer while preventing an occurrence of a phase where no current flows. An induction heating system uses the three-phase AC power supply to run the induction heating apparatus including an induction heating coil, and has an intermediate apparatus including a coil that is wound on an iron core with an even number of turns, forming a closed magnetic circuit. Additionally, a winding start point of the induction heating coil is connected to the U phase of the three-phase AC power supply and a winding end point of the same is connected to a midpoint of the intermediate coil. The winding start point and end point of the intermediate coil are connected to the V and W phases of the three-phase AC power supply, respectively.

An electronic induction heating cooker is provided. The electronic induction heating cooker may include a rectifier that rectifies an input voltage into a direct current (DC) voltage and output the DC voltage, an inverter including first, second and third switches connected in series between a positive power source terminal and a negative power source terminal to generate an alternating current (AC) voltage by switching the DC voltage, a first heater driven by the AC voltage so as to heat a first cooking container, a second heater connected in parallel to the first heater and driven by the AC voltage so as to heat a second cooking container, and a switching controller that generates a switching signal for controlling the first and second heaters in accordance with a set of operating conditions input thereto and adjusts a duty cycle of the switching signal.

An induction heating container (1) in which an induction heat generator (3) is attached to the inside of a container main body (2) made of a non-conductive material so as to enable cooking by heating by an electromagnetic cooker. The induction heat generator (3) includes: a laminated body involving a conductor layer (4) that generates heat by induction of eddy current by high-frequency magnetic field and a heat-seal layer (5) that imparts heat-sealing properties to the container main body, and an eddy current control part (6) obtained by cutting the conductor layer (4) along the circumferential direction.