Abstract: A heating circuit for heating a conductive bowl includes a voltage source; a first heating coil provided between first and second nodes and being configured to heat the conductive bowl; a second heating coil provided between the second node and a third node and being configured to heat the conductive bowl; first capacitor and first switch provided in parallel between the first node and a fourth node; and second capacitor and second switch provided in parallel between the third node and the fourth node. The first and second heating coils define a circle-like shape having a center. The first and second heating coils are configured to be aligned to each other if one of the first and second heating coils is moved with respect to a line extending through the center of the circle-like shape.

Abstract: An induction heating cooking device has an inverter including a resonant circuit, and a heating output control part. The resonant circuit has a resonant capacitor and a heating coil that is magnetically coupled to a load. The inverter has first and second switching elements. The heating output control part performs control by inverting the rate values of the driving periods of the first and second switching elements. The driving of the inverter is thus controlled so that substantially the same heating output is obtained to average the losses of the first and second switching elements.

Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.

Abstract: A heater for a hob or cooktop having a glass ceramic surface is disclosed, whereby a number of individual modules with induction coils are provided with converters and a converter control for each induction coil. The modules may be independently assembler and/or replaced, and are arranged close together beneath the glass ceramic hob and electrically connected to a busbar. Each module may be controlled separately. A heated surface of using various combinations of modules can thus be achieved.

Abstract: A converter (311) converts an AC electric power (e) to the DC electric power with a DC voltage value corresponding to a setting. An inverter (312) is controlled by a frequency electric power control circuit (330) to convert the DC electric power to a dual frequency AC electric power for alternately outputting low and high frequencies at a frequency ratio (duty) corresponding to the setting. A matching transformer (321) having a tap (321C) at which the resonance impedance corresponds to the output impedance of a generator (310) receives the dual frequency AC electric power. A low-frequency series resonance circuit (325) or a high-frequency series resonance circuit (326) is caused to provide a series resonance, thereby causing an induction heating coil (200) to induction heat a workpiece-to-be-heated (201). In this way, the single generator (310) and the single induction heating coil (200) are used to effectively induction heat the workpiece-to-be-heated (201) by means of the dual frequency resonance.

Abstract: An apparatus and process are provided for multi-frequency induction heat treatment of workpieces including gears. High frequency power is applied to an induction coil that surrounds the workpiece so that a high frequency magnetic field couples with the workpiece to inductively heat the workpiece. A C-core inductor is coupled to a coil that has low frequency power applied to it. The workpiece is inserted in a gap in the C-core inductor magnetic circuit so that it experiences low frequency Joule effect heating when the low frequency current is applied to the coil coupled with the C-core inductor. Alternatively the workpiece may be inserted around the C-core inductor when the workpiece has an opening.

Abstract: An apparatus (10) and method for preheating welds uses a centered induction plate (12) having preferably a plurality of induction coils (30, 32) to impart the generation of heat in the materials to be welded (14), being interactively controlled by at least a temperature sensor (90, 92) and power supply control loop (16) so that even preheating can be obtained for a selected length of time given the parameters of the weld desired.

Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.

Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit 400 according to the present invention is provided with control units 420 (420a to 420d) respectively corresponding to a plurality of heating units 310 (310a to 310d). A phase detector 424d of the control unit 420d obtains a phase difference between an output current (heating coil current IL4) of an inverter 314d detected by a current transformer 160d and a reference signal outputted by a reference signal generating section 426, and inputs it to a drive control section 422d. The drive control section 422d adjusts an output timing (phase) of a gate pulse to be given to the inverter 314d so as to make a phase of the heating coil current IL4 of the inverter 314d coincide with a phase of the reference signal outputted by the reference signal generating section 426.

Abstract: A high frequency induction-heating device 3 of the apparatus 1 for heating work includes a pair of opposite work coils accommodated within the coil casings 17 and 19 respectively. The casings 17 and 19 can be displaced in a unit by a motor provided under the device. Thus, the distance between the pair of work coils, and the distance between the work (W) and each work coil can be adjusted. The apparatus includes a plurality of heating devices 3 to which high frequency power sources are provided respectively. The apparatus and method for heating of a work with the apparatus is capable of treating a plurality of works (W) continuously under controlled conditions on work coil shapes and positions depending on the size and/or the shape of the works (W).

Abstract: A frying arrangement includes a planar heating element (5) including a ferromagnetic material and constituting a frying surface. The arrangement includes at least two magnetic field generators (1, 2) each having two free ends, wherein the heating element is arranged in or close to a plane defined by the free ends. The magnetic field generators are controlled by a controller such that they are adapted to generate alternating magnetic fields in the planar heating element, wherein the magnetic fields are converted into heat in the heating element. The magnetic fields being such that the magnetic field through one of the free ends has an opposed direction as compared to the magnetic fields through the other free ends.

Abstract: According to some embodiments, a control signal is generated to reduce resonance of a circuit at an operation point, a characteristic of the control signal based on a proximity of an existing operation point to the operation point. Generation of the control signal may include sensing of a current associated with an input voltage signal, generation of a current-based signal based on the sensed current, and generation of the control signal based on a phase difference between the current-based signal and the input voltage signal.

Abstract: The image heating apparatus includes a heating member, a first coil unit having a first holder in which a first excitation coil is sealed, the first excitation coil being provided for generating a magnetic field to induce an eddy current in the heating member, and a second coil unit having a second holder in which a second excitation coil is sealed, the second excitation coil being provided for generating a magnetic field to induce an eddy current in the heating member. The image heating apparatus having such structure enables easy assembly work while being capable of conducting nonuniform heating.

Abstract: The image heating apparatus includes a heating member, a first coil unit having a first holder in which a first excitation coil is sealed, the first excitation,coil being provided for generating a magnetic field to induce an eddy current in the heating member, and a second coil unit having a second holder in which a second excitation coil is sealed, the second excitation coil being provided for generating a magnetic field to induce an eddy current in the heating member. The image heating apparatus having such structure enables easy assembly work while being capable of conducting nonuniform heating.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF control led by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: A device for inductive billet-heating includes a single or multi-layer billet-heating coil (4) for a round billet (5), in which the billet-heating coil (4) is made up of one or more consecutive, galvanically separated zones. The zones are supplied with electrical energy from a three-phase network by means of an electrical switching device and a control unit. The billet-heating coil (4) includes multiple, synchronically regulated zones (Z1, Z2 through Zn) with reference to frequency and phase of inductive field. For a current feed to each zone (Z1 through Zn) of the billet-heating coil (4), a converter (2) with variable frequency and a plurality of modules is provided. The converter includes plurality of power-moderate closed units with DS-network feed and synchronization of phase and frequency of an output voltage.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: For optimum induction heating of metallic strips (1) of differing widths—particularly in the edge region—one multicoil transverse field inductor is positioned both above and below the strip (1) to be heated, whose coil axes are positioned vertically to the strip surface. In this case, each inductor comprises at least one inductor segment (2, 3; 7; 15; 17), which is constructed as a coil composite of multiple approximately rectangular coils (8, 9, 10; 16; 18) which extend predominantly transversely to the transport direction of the strip (1), the coils (8, 9, 10; 16; 18) having different, stepped transverse extensions and the coil having the highest transverse extension extending at most up to the lateral edges of the widest strip and the coil having the lowest transverse extension extending at most up to the lateral edges of the narrowest strip.

Abstract: A rectifier/inverter power supply for use with induction heating or melting apparatus includes a tuning capacitor connected across the output of the rectifier and input of the inverter. The tuning capacitor forms a resonant circuit with an inductive load coil at the operating frequency of the inverter. Additionally, the load coil may be formed from an active load coil connected to the output of the inverter and a passive load coil, in parallel with a resonant tuning capacitor.

Abstract: A device for heating a roll in a paper or paperboard machine or in a finishing machine for paper or paperboard the device including a profiling induction heater (5) which is arranged to heat the roll (3) with a power dependent on the location of the point to be heated in the axial direction of the roll, and a non-profiling induction heater (4) which, to provide basic heating, is arranged to heat the same roll (3) with a heating power which is substantially even over the width of the roll (3). The profiling induction heater (5) and the non-profiling induction heater (4) are placed in the same support structure (1) outside the roll (3). The roll (3) is a calender roll.

Abstract: A spatula heating apparatus with excellent usability which overcomes drawbacks inherent to conventional gas burner type and electro-thermal type apparatuses. A spatula heating apparatus for heating spatulas 9, 9a for wax molding includes a heating coil 8 for induction-heating of spatulas 9, 9a, a heating amount setting switch 5, and an inverter control circuit 21 for supplying high frequency current to the heating coil 8 to perform heating at a preset heating amount. When high frequency current is applied to the heating coil 8, the spatulas 9, 9a are heated at the preset heating amount through electromagnetic induction.

Abstract: The method and apparatus are for use in automotive vehicle repair, both mechanical and body. The apparatus includes at least an eddy current/hysteretic circuit and at least one applicator functionally engaged to the circuit for obtaining a desired result when the applicator is placed into contact with structure of the vehicle to be affected by heating thereof.

Abstract: A tool (38) secures and releases a fastening arrangement which includes a first component (10) and a second component (12) which may be releasably fastened together. Fastening is by means of a retention element (34) of shape memory material associated with the second component (12) which is reconfigurable between an open position (first and second components separated) and a closed position (first and second components fastened together). During fastening a closure element (36) urges the retention element (34) from its open position to its closed position. The tool includes a magnetic coil (44) energizable to urge the closure element (36) in a direction to cause the retention element (34) to move from its open to its closed state. The magnetic coil (44), or an additional coil, is also energizable to draw the closure element (36) away from engagement with the retention element (34). A heating coil (45) is provided for heating the retention element (34).

Abstract: A plurality of billets are inductively heated in a staged process wherein the output current of a power supply is repeatedly time shared among a plurality of induction coils within which the plurality of billets have been placed. The time periods of the applied current to each coil become sequentially shorter over the total heating time of a billet to allow magnetically induced heat to conduct to the center of the billet during the dwell periods between applied electrical current periods. This maximizes the efficiency of the output of the power supply while melting of the outer regions of a billet is avoided in a process wherein the billets do not have to be moved during the overall billet total heating time.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: An induction heating device for heating cooking vessels includes at least three concentric inductors and implements a step of heating a load. For a load covering at least three inductors, at least one intermediate inductor that is covered and that is determined in such a manner as to homogenize the input of heat to the load is not energized during the heating step. Applications of the device include domestic hot plates.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: A portable induction heating system which utilizes a broadband high frequency high-power, low output impedance power generator formed from switching MOSFET devices. A voltage-controlled oscillator (VCO) or microprocessor-controlled signal generator drives a power output stage under feedback control so as to effectuate resonance at a high frequency in an induction coil assembly connected to the power generator. The power generator is operable with a switching regulator that can supply a fixed DC voltage, e.g., 12 to 48 V or a variable setpoint. The induction coil assembly includes a capacitive circuit portion connected to a conductive coil that can couple magnetic field to a susceptor. A microcontroller is provided for inputting operating parameters such as power, frequency, duty cycle and duration, and is operable to auto-tune the VCO output under feedback control by sweeping frequency at startup as well as by controlling drift during operation under a changing load.

Abstract: An induction heating roller apparatus that varies temperature distribution in the axial direction of a heating roller. The apparatus includes a heating roller and a plurality of induction coils arranged separately along an axial direction of the heating roller. The heating roller includes a secondary coil that is air-core transfer coupled to the induction coils. The apparatus further includes a plurality of capacitors, each being connected to one of the induction coils to form a resonance circuit. At least one of the resonance circuits has a resonance point that differs from the remaining resonance circuits.

Abstract: The invention concerns an induction cooking hob with multiple inductors fed at the same frequency or multiples of a common fundamental frequency to avoid beat frequencies. Separate generators are provided for two or more heaters. A high-power heater is provided with two or more inductors. To provide maximum power, the second inductor of the high-power heater may be supplied with power switched from the generator for a different heater.

Abstract: An induction heating roller apparatus that varies temperature distribution in the axial direction of a heating roller. The apparatus includes a heating roller and a plurality of induction coils arranged separately along an axial direction of the heating roller. The heating roller includes a secondary coil that is air-core transfer coupled to the induction coils. The apparatus further includes a plurality of capacitors, each being connected to one of the induction coils to form a resonance circuit. At least one of the resonance circuits has a resonance point that differs from the remaining resonance circuits.

Abstract: An induction heating apparatus used as a fixing apparatus of a copying machine, a printer, and the like includes a first coil for generating a magnetic field to induce an eddy current in a heating member, a second coil for cancelling the magnetic field generated by the first coil, and a third coil connected to the second coil and wound in a direction opposite from the winding direction of the second coil. The induction heating apparatus permits an efficient use of power.

Abstract: A method and apparatus for induction heating includes a power supply, and a controller, and an induction head. The induction head includes a flexible coiled, such as one formed with Litz wire. The head also includes a thermal insulator, for disposing between the head and the workpiece. The insulator reflects heat back to the workpiece, protecting the coil, but is transparent to inductive (E-M) energy. The power supply is a variable output frequency power supply, such as one having a resonant tank, to adapt to the inductance of the head.

Abstract: The present invention has an object to provide an induction-heating fusion device which is capable of stabilizing the fusing temperature over the entire width of a sheet therethrough by inhibiting an excessive temperature rise in a sheet-nonpassing zone defined when a small-size sheet is subjected to fusion. The induction-heating fusion device according to the present invention includes an iron core 17 forming a closed magnetic circuit, a main induction coil 14a wound around the iron core 17 for generating a magnetic flux which causes an electrically conductive member to generate an induction current circumferentially thereof, and at least one induction sub-coil 14b provided on an end portion of the main coil for generating a magnetic flux which causes the electrically conductive member to generate an induction current circumferentially thereof.

Abstract: An induction heating systems using a plurality of zones in a coil provides selective heating control for better uniformity especially for semiconductor and other thin film processing applications. By arranging the zones to have different resonance frequencies, the power supply may control the various zones by altering its frequency output. The power supply may also act to control the differential heating by switching among zones in conjunction with the frequency control, by sweeping through a variety of frequencies, by simultaneously providing power over different frequencies, by altering the residence time at each frequency, or by outputting different powers to each frequency or the like. Each zone may thus be tuned as appropriate to achieve the desired induction heating characteristic.

Abstract: An induction heating appliance has magnetically active parts on the top and is otherwise completely encapsulated in an electrically insulating and heat conductive material. The electrical connection is by means of a plug. A number of such appliances may be supplied with power in the range 20 kHz-100 kHz via coaxial cables leading to a central power supply converter. The unit is intrinsically safe and can be either installed or free standing.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: According to the invention, the rear end of a preceding metal piece and a front end of a succeeding metal piece are heated, pressed and joined prior to the finishing hot rolling. An alternating magnetic field running through the metal pieces in the thickness direction thereof is generated in an end region on opposed faces of the respective metal pieces to perform heating. Another alternating magnetic field whose direction is reverse with respect to that of the former alternating magnetic field is partially generated in the end region on the opposed faces of the metal pieces and in either a region where the metal pieces exist or a region outside width ends of the metal pieces. This assures a uniform heating of the end region on the opposed faces of the metal pieces over their full width to reliably join the both metal pieces to each other.

Abstract: There are provided an induction heating coil for carrying out high frequency induction heating (heating during movement) of a hot rolled steel or the like by surrounding the hot rolled steel or the like which is placed on a plurality of conveying rollers and conveyed, and an induction heating apparatus using this induction heating coil. In an induction heating coil 2 for induction heating a heated body (a thin slab 8 or the like) by surrounding it, a first coil portion 13 wound in a spiral form while transferring in one direction (the direction of the arrow mark &agr;) along a coil axis S and a second coil portion 14 which is connected to a terminal (turn point 18) of the first coil portion 13 and wound back while transferring in the other direction (the direction of the arrow mark &bgr;) along the coil axis S are combined so as to overlap in the non-contact state.

Abstract: A method and apparatus for induction heating includes a power supply, and a controller, and an induction head. The induction head includes a flexible coiled, such as one formed with Litz wire. The head also includes a thermal insulator, for disposing between the head and the workpiece. The insulator reflects heat back to the workpiece, protecting the coil, but is transparent to inductive (E-M) energy. The power supply is a variable output frequency power supply, such as one having a resonant tank, to adapt to the inductance of the head.

Abstract: The present invention relates to an induction heating apparatus for heating an image on a recording material which has an electric conductor, a first coil, for inducing an eddy current in the electric conductor disposed over a longitudinal direction of the electric conductor, a second coil disposed so as to overlap an end portion of the first coil, a first power supply for supplying an alternating current to the first coil, a second power supply for supplying an alternating current to the second coil, a phase shifting circuit for controlling a phase of the alternating current supplied to the second coil, and control means for controlling the phase shifting circuit in conformity with a temperature of the electric conductor.

Abstract: A furnace for heating ferrous metal workpiece is made up of a plurality of pairs of furnace sections with each pair of furnace section having a longitudinal flux inductors with controls for rapidly adjusting the heating rate according to a desired workpiece discharged temperature from the second of the furnace sections. The second furnace is controlled to maintain a substantially constant workpiece heating temperature. A second pair of furnace sections is provided with a first furnace section utilizing coil pairs with a dual output power supply having independent phase adjustable output currents to vary the current phase relation between the coils between 0 and 180°. The change to the phase relation is used to maintain efficient heating of the metal strip above the Curie temperature.

Abstract: An induction furnace having a voltage source series inverter, a load circuit having a combination of an induction coil and a resonating capacitor bank, and control circuitry to phase lock the inverter frequency to the natural resonant frequency of the load. The capacitor bank can be divided into two groups, one across the output of the inverter and the other in series with the load. This arrangement allows for the division of the inverter voltage across the furnace coil according to the ratio of the two capacitances. The inverter uses pulse width modulation and is buffered from the load circuit by means of a small series connected inductor. Additionally, the system can have a common power supply system that supplies power in any desired proportion to a plurality of induction furnaces.

Abstract: An induction heating system having at least one power supply switching network is disclosed to provide selective power control to multiple zones of an induction heating coil to achieve a desired heat distribution in a workpiece. The power supply switching network includes a number of bidirectional switches, each connected in series with one another, and each connected in parallel with a portion, or zone, of an induction heating coil. The bidirectional switches are controlled by a computer that supplies a control signal having a duty cycle as determined by the computer and a multi-zone feedback circuit. By splitting the coils and inserting a switch in parallel with each coil, and each switch in series with one another, the coil is effectively split into multiple series connected coils, thereby being more effectively controllable while avoiding physical alterations to the heating coil.

Abstract: A system and method for inductively heating a workpiece includes a controller and a plurality of power supplies that receive and send signals to the controller. Induction heads receive power from the power supplies. The induction heads may be aligned with adjacent segments of the workpiece, and can span the perimeter of the workpiece. The gap between adjacent induction heads is less than one half the size of the adjacent induction heads, and preferably the induction heads abut or substantially abut. Each of the power supplies include feedback for controlling the power delivered to the segments of the workpiece. In alternative embodiments the feedback may be based on the current or power provided to the induction heads, or the power provided to the workpiece.

Abstract: The present invention provides a circuit for heating a heating element to a desired temperature and generating an output from a single common AC power source. First, the AC power is rectified. An inductor and a capacitor form an L section type filter for the DC from the rectifier. The inductor and the capacitor have a resonate frequency that is greater than the AC power frequency. A switch is connected to the heating element. Next, a controller receives a signal that indicates the actual temperature of the heating element along with an indication of the desired temperature. The controller generates an error signal that PWMs the switch thereby controlling the heating element. Another switch is connected to a transformer. A separate controller PWMs the second switch generating the output at the secondary side of the transformer. The two controllers use a pulse width modulating frequency that is greater than the resonate frequency of the inductor and capacitor.

Abstract: A method of joining or welding of at least a portion of a first metal workpiece to at least a portion of one or more second metal workpieces, comprising inducing movement in said portion of the first workpiece by means of a pulsed magnetic force so as to impact said portion of the second workpiece, the movement imparting a kinetic energy on the at least portion of the first workpiece to cause the two at least portions to join or weld to one another.

Abstract: A device for inductive cross-field heating of flat metallic goods has at least one pair of inductors having each one iron core provided with a groove for receiving a lead that extends in the transport direction. The grooves and leads of both inductors of a pair of inductors are mirror symmetrical and the leads of each inductor form two independently switchable lead systems. Each lead system has sections that extend substantially in the transport direction of the metallic goods and whose center lines extend symmetrically to a central axis of the inductor parallel to the transport direction. The individual poles of the lead systems consist of maximum two leads. Each pole of a lead system is arranged between the poles of the other lead system. A uniform temperature distribution in the goods to be heated is achieved by synchronizing the offsetting in time the moments when both lead systems are switched.