DE2042843A1 - Power supply unit for operating a magnetron - Google Patents

Description

• PAT «NTANWALTR

DIPL.INC. H. LEINWEBER dipping. H. ZIMMERMANN

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Zuh 1970 PüS-23119 ö »n 2b. August Z / Va

MATSUSHITA ELECTRIC

Cu., 1Λ1)., Usaka / Japan

power supply unit for operating a magnetron

The invention relates to a chaser for operating a Magnetrons to make it vibrate, especially a compact power supply that is used in electronic Cooking is suitable, with food supplied by an I-lagnetron generator generated high frequency energy can be cooked.

Further details, advantages and features of the invention emerge from the following description, on the Drawing illustrates the invention by way of example, namely show

Fig. 1 is a circuit diagram of a known power supply for

a magnetron generator,
FIG. 2 is a circuit diagram of the one shown in FIG

wetzgerät used main transformer, Fig. 3 to 6 circuit diagrams of different embodiments of the device according to the invention,

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Figures 7 to 10 are schematic representations of the basic features the transformer used in the device according to the invention and

11 to 14 illustrate the operation of the transformer Schematic tables Jjar st el rangen.-

1 shows a circuit diagram of a known power supply unit with a scatter transformer T , which is used as the main transformer. As Fig. 2 shows, the main transformer a Primärspul-e 1 and a secondary coil 2 _s which are wound around the center leg of the core 5 and between which a pair of magnetic leakage paths are arranged eye. 6 Terminals 7, 6 are provided at the ends of the primary coil 1 and terminals 9, 10 are provided for the secondary coil 2. The device also has a transformer Tp sura supplying energy to a magnetron Mg to the hot cathode, a rectifier , a capacitor C, contacts MS of a magnetic breaker, a magnetic coil MSC of the breaker and a button switch SM. There are also terminals 11, 12 which are connected to power lines. If you press the button switch SW and thereby close the contacts MS, the primary winding 1 of the transformer T * is excited, in the secondary circuit of the transformer the magnetron Mg and the rectifier B are connected in parallel, but in opposite directions - measurement parallel connection is with the accounts AT 0 connected in Böihs " XH β primary winding 3 of the two-line fenafornatora T" is also connected to terminals 11, 12, while the secondary winding 4 of this transformer is connected to ;; ij.ihodeaheizer äss fegnstrons is switched, soiii awoi wi'ansforiaatoreii are required to operate the magnetrongtngratars. If the bsicbn Transforaatortn are combined to ■ 6in "e, indeiü aan the known main tranforma"

■ • β Ä «m

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tor a with a third winding for the cathode heater, the third winding is also energized or de-energized when the contacts MS are closed or opened. this becomes a Voltage applied to the anode of the l-iagnetron before the Cathode has been heated enough to give off enough electrons, thereby causing an abnormal vibration High voltage pulses are generated. So it is with the conventional Devices impossible to combine the iiei z transformer with the main transformer to form a single unit.

"The invention is intended to be a compact and inexpensive network device be created for a l'lagnetron generator that has one contains a single transformer that performs both the function of the above-mentioned main transformer and that of the filament transformer Has. ·

In the case of the power supply unit according to the invention, the high-voltage secondary circuit controlled simply by switching the magnetic breaker while the heating circuit is live remain. JÜie invention has the further advantage that when Opening the oven door while working will put the magnetron generator out of service if it is more reliable '' The leakage of the harmful high frequency wave is prevented.

To achieve this goal, the inventive power supply for a magnetron generator on a transformer, which has a three-legged magnetic core, which is provided with two primary winding halves, each on one of the outer Legs of the core are wound, furthermore with a secondary winding wound on the middle leg of the core

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for applying a high voltage to the magnetron and one on one of the outer legs of the core wound third winding for charging the cathode of the magnetron with heating energy. In addition, there are holding devices with the primary winding halves connected by leasing the through one of the primary winding halves generated magnetic flux can be varied in relation to that of the flux generated by the other, the two Primary winding halves are connected in parallel.

In the following, the power supply unit according to the invention is based on various embodiments explained. Figures 3-14 show primary winding halves 101, 101 'and a secondary winding 102. In the arrangements shown in FIGS the secondary winding consists of two equal parts. A third winding 103 supplies power to a cathode heater. Further The figures show a fourth winding 104, the core 105 of the transformer and interconnecting cores forming magnetic leakage paths 106. Terminals 109, 110 are to be connected via the load circuit, which includes a magnetron Mg, a rectifier D, which is connected in parallel and in opposite directions with the magnetron and includes a capacitor C which is connected in series with the parallel connection of magnetron and rectifier.

The operation of the power supply unit according to the invention is explained below with reference to FIGS. 3, 7, 11 and 12. It is assumed that the contacts MS of the magnetic breaker normally connect the coil terminal 107 to the terminal 106 'and the pin 108 to the terminal 107', as shown in FIG. 3; the primary winding halves 101, 101 'are created by applying the

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Nominal voltage at terminals 115, 11b excited in opposite directions, so that the magnetic fluxes 0, and 0 'generated by the windings 101 and 101' cancel each other out in the middle leg and only a small one, the difference 10. - JZL ¹ I corresponding voltage is induced in the secondary winding 102. When the rivers are 0-, and 0. ' are exactly the same, no voltage is induced in the winding 102. When the switch SW is then depressed to toggle the contacts rlS so that the terminal 107 is connected to the terminal 107 * and the terminal 108 is connected to the terminal 108 ¹ , the windings 101 and 101 'are energized in the same direction, correspondingly the rivers jZL and 0. ' are added to one another in the middle leg, as shown in FIG. 11, and a voltage corresponding to \ 0 _Λ + 0..M is induced in the secondary winding 102. The voltage induced in winding 102 is high enough to cause the magnetron to oscillate. Stray fluxes 0p, 0p ¹ according to FIG. 11 are generated when the load current flows through the secondary winding 102. It can be seen from FIGS. 11 and 12 that, regardless of the switching position of the contacts MS, the flux 0 .. induces a voltage of essentially constant amplitude in the third winding 103. Therefore, the heater of the magnetron cathode remains energized regardless of the type of connection between the two primary winding halves. In other words, the magnetron can be vibrated or brought to a standstill while the cathode remains heated by an essentially constant energy.

The same result is achieved when using a transformer shown in FIG. 8 or FIG. 9.

A further implementation of the invention is ii consequences described the reference to Figures 4, 10,. 13 and 14 It seems like

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assumed that the nominal voltage is applied to terminals 115 »116 and the button switch SW has not yet been depressed. As the contacts MS connect the terminal 107 * »it of the terminal 11b and the terminal 10b to the Kieianje 108 ¹ , as shown in FIG. 4, the primary cradle halves 101, 101 'are excited in opposite directions. In this way, the fins 0 ^ and 0 ^ generated by the winding halves 101 and 101 * cancel each other out in the middle leg of the kneading core, as can be seen from FIG. 14. A voltage is induced in the third winding 103 and therefore the heating current flows through the winding 103. Ua this heating current generates a magnetic flux j2L in the direction opposite to the flux 0. Another current flows through the primary winding half 101, creating an opposing magnetic flux jZL "Is generated, which reverses the flow jZL. Since the primary winding halves 101 and 101 »are connected in legs, the same additional current flows through the winding 101 * and creates an additional flux 0 ^% *„ * which flows through the middle leg of the core. A fourth winding 104 is around the middle leg wrapped. Terminals 113 and 114 are connected to each other by additional contacts of the same breaker if the button switch SW has not yet been depressed. Furthermore, a current flows through the winding 104, which generates an opposing magnetic flux 0 , which cancels the FIuB 0 * ". As can be seen from this description _; no voltage is induced in the secondary winding 102 until the button switch SW is depressed. By pressing the switch SW for exciting the magnet coil MSC, the contacts are switched in such a way that the terminal 10b is connected to the terminal 107 * and the terminal 108 * is connected to the claw 116 and, furthermore, the terminals 113 and 114 of the fourth winding 104 are switched off. Flow into this state

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the magnetic fluxes in the core as in H ^. Represented 13 üuf this way, the generated by the PriinärwickJungert FJfsße 0 ^ and # ■ ties in nattiereri leg core? just a rider adcUerl. Meanwhile, a voltage is induced in the third winding, whereby a current flows through the cathode heater of the magnetron: ι can. Lüeser's heating current generates the magnetic flux 0 ^ in the direction opposite to the flux 0, which in turn induces an opposing flux 0yj , which is maintained in the winding 101 by an additional current. Among other things , the primary winding halves 101 and 101 * are connected in series, a flux 0 \ u corresponding to the flux $ _1H ^{"is generated by the winding TOl 1} , which flows through the middle limb of the core. The total flux is in the middle limb

In this way, a high voltage is induced in the secondary winding 102 which is sufficient to operate the magnetron. After energizing the magnetron, the load current generates flows 0 ₂ ^un ^ $ 2 ' which flow through the scattering paths 10b. As the above description shows, the third winding 103 always generates a voltage of a substantially constant amplitude regardless of the position of the contacts. Therefore, the magnetron can be turned on or off while the cathode remains heated. The fourth winding need not necessarily be a separate winding, but it can be provided as a part or an extension of the secondary winding.

5 shows a further embodiment of the invention. In this embodiment, the structure and operation of the Transformer similar to that described in connection with FIG. A special feature of this embodiment is the The fact that door switches connected to the oven door

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with the normally open contacts of the magnetic sub-turner connected in series. With this arrangement, it is ensured that the oscillation of the magnetron is stopped if the oven door is opened during operation, thereby preventing the radio frequency wave from being radiated from the oven. It is clear that a similar effect is obtained with a single door switch, If an additional door switch with the magnetic coil MSC of the magnetic interrupter is switched to None, the associated switch-off of the oscillation is even better ensured, since the secondary voltage is canceled ^{by switching the contacts I 1 IS} will.

In yet another embodiment of the invention, shown in FIG. 6, the door switch is switched via the terminals 113 and 114 of the fourth winding 104. This door switch is opened or closed when the door is closed or opened. The remaining components of the device illustrated in FIG. 6 are the same as those in FIG. 4. If the door is opened during operation and the door switch is closed, a magnetomotive force is generated which cancels the flux in the itted leg . Thereby, the voltage induced in the secondary winding 102 is decreased, whereby the oscillation of the magnetron is stopped and the leakage of the high-frequency wave is prevented.

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Claims (1)

Patent claims: t. A power unit for a magnetron generator, characterized by a transformer (T) with a three-legged magnetic core (105), two primary winding halves (101, 101 ), each wound on one of the outer legs of the core, a secondary winding ( 102) for applying a high voltage to the magnetror (Mg) and a. Third winding (103) wound on one of the outer legs of the core for charging the cathode of the magnetron with heating energy, and by switching devices (SW, HS) connected to the primary winding halves (101, 101) for changing the direction of one of the primary winding halves generated magnetic flux in relation to that of the flux generated by the other primary winding half, wherein the two primary winding halves (101, 101 ') are connected in parallel (Fig. 3, 7). 2, power supply for a magnetron generator, characterized by a transformer (T) with a three-legged magnet core (105), two primary winding halves (101, 101 '), each wound on one of the outer legs of the core , two each on one of the outer Secondary winding halves (102) wound on the legs and connected in series for applying a high voltage to the magnetron and a third winding (103) wound on one of the outer legs of the core for charging the cathode of the magnetron with heating energy, and by bit the primary winding halves (101, 101 ') connected switching devices' for changing the direction of the magnetic flux generated by one of the primary winding halves in relation to that of - 10 - 108811/1834 the other primary winding half generated flux, the Primary winding halves are connected in parallel (Fig. 8). 3.. Power supply unit for a magnetron generator, marked by a transformer with a three-legged core (105), between the middle limb and the respective outer limb, the middle limb is divided into two equal parts dividing magnetic flux-connection path (106) is provided, further with two half-fairing halves (101, 101 ") each wound around one of the parts of the central leg of the core, with two secondary winding halves (102) each wound around one of the two parts of the central leg of the core, which are connected to one another are connected in series and are suitable for applying a high voltage to the magnetron, and with one around one the two parts of the central leg of the core wound third winding (103) for charging the cathode of the magnetron with heating energy, and by switching devices connected to the primary winding halves (101, 101 *) for changing the direction of the magnetic flux generated by one of the primary winding halves in relation to that generated by the other primary winding half Flux, the two primary winding halves are connected in parallel (Fig. 9). 4.! Power supply unit for a magnetron generator, marked by a transformer with a three-legged core (103), two primary winding halves (101, 101 ') each wound on one of the outer legs of the core, one on the middle one Leg of the core wound secondary winding (102) for applying a high voltage to the magnetron, one around one of the outer leg of the core wound third winding (103). - 11 - 109811/1834 for charging the cathode of the riagnetron with heating energy and a fourth winding (104) wound around the central leg of the core, further through one with the primary winding halves (101, 101 ') connected first switching device for changing the Thinning of the flow generated by one of the primary winding halves in relation to that of the other primary winding half generated flux, whereby both primary winding halves are switched to none, and by one via the terminals (113, 114) of the fourth winding (104) connected to the second switching device, which is connected to the first switching device that the fourth winding is closed when the fluxes cancel each other due to the primary winding halves, and the fourth Winding is open when the fluxes due to the primary winding halves are added together (Fig. 4, 10). 5. Power supply unit according to claim 4, characterized in that at least one normally open contact of the first switching device with a door switch is switched to none, the is open when the door is closed. b. Network device according to Claim 4, characterized in that the fourth winding (104) is connected to a door switch which is closed when the door is open. 109811/1834