JPH02223187A - Oven range - Google Patents

Abstract

PURPOSE:To prevent unnecessary operation of a magnetron at the time of cooking with an oven by a heater by closing a heater circuit of the magnetron at the time of electric application to the heater for cooking with an oven. CONSTITUTION:When a selection switch 18a is turned on, an electricity is applied to a heater 17 so as to carry out cooking with an oven and in this case, a switching means 19b is turned off so as to close a heater circuit 24 of a magnetron 20. Therefore, if voltage of power sources are different like 100V and 200V and in the case that a primary coil 10 of a high voltage transducer 9 is so installed as to changes tups without a power source transducer, a heater circuit closing relay 19 is operated at the time of electricity application to the heater 17 for cooking with the oven so as to close the heater circuit 24 of the magnetron 20 by a closing contact 9b. Thus, the magnetron 20 is not operated unnecessarily at the time of cooking with the oven.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to electric F1. The present invention relates to a microwave oven that can handle different voltages such as 100V and 200V (7).

(Prior art) Commercial power supply voltage is mainly 100V in Japan, but it is 200V.
V is also becoming popular, and in other countries, for example, 100V, 20V
There are various situations where 0V or both are used together. For this reason,
Even in the microwave oven, the rating is 100 or 200.
It is desirable to take measures such that products manufactured with a V rating can be used even if the commercial power supply voltage is different. The easiest way to deal with this would be to use a tap-switchable power transformer, but microwave ovens are equipped with a high-voltage transformer to supply high voltage to the magnetron. If a power supply transformer is further provided in addition to the above, there is a problem in that the cost increases.

Therefore, in the past, the primary coil of a high voltage transformer was
In addition to providing taps for V and 200 mm, a tap changeover switch is installed to change the taps, and a fan motor for cooling the magnetron and a heater for oven cooking are connected to the taps that match their respective ratings. , a selection switch is connected in series to the heater. When performing high-frequency heating cooking, turn off the selection switch to disable the heater and operate the magnetron connected to the secondary coil of the high-voltage transformer; when performing oven cooking, turn off the selection switch. When the heater is turned on and activated, current is supplied to the heater from the tap of the primary coil of the high-voltage transformer to operate the heater.

(Problems to be Solved by the Invention) In the conventional configuration, even when oven cooking is performed using a heater, commercial power supply voltage is applied to the primary coil of the high voltage transformer, so high voltage AC voltage is applied to the secondary coil of the high voltage transformer. There is a problem in which the magnetron operates due to the induction of

The present invention has been made in view of the above circumstances, and its purpose is to cope with the case where the power supply voltage varies by changing the tap of the primary coil of a high-voltage transformer. There is a microwave oven provided that never works.

[Structure of the Invention] (Means for Solving the Problems) The microwave oven of the present invention has a predetermined electric component and a heater connected in series with a selection switch on the primary coil side of a high-voltage transformer, and a heater on the secondary coil side. By connecting a magnetron and changing taps of the primary coil for different power supply voltages, a rated voltage is applied to the electric component and the heater via the selection switch, and the selection switch The present invention is characterized in that it includes a switch means for turning off the heater circuit of the magnetron when the heater is energized by the magnetron.

(Function) According to the microwave oven of the present invention, when the selection switch is turned on, the heater is energized and oven cooking is performed, but in this case, the switch means is turned off and the heater circuit of the magnetron is cut off, so that the magnetron is turned on. It never works.

(Example) An example of the present invention will be described below with reference to FIG.

1 is a power plug, one terminal of which is a fuse 2.
Normally open contact 4 of first door switch 3 and power relay 4
a in series to the power supply line 5, and the other terminal is connected to the power supply line 7 via the second door switch 6. A short switch 8 is connected between the common connection point of the fuse 2 and the first door switch 3 and the other terminal of the power plug 1. In this case, the door switches 3 and 6 are turned off and on according to the opening and closing of the door of the microwave main body (not shown), and the short switch 8 is turned on and off in conjunction with the off and on of these door switches 3 and 6. It looks like this. 9 is a high voltage transformer, which includes a primary coil 10 and secondary coils 11 and 12. The primary coil 10 is one terminal, Ov terminal 10a.
, has a 100V tap 10b serving as an intermediate tap and a 200V tap 10c serving as the other terminal, and its O
The V terminal 10a is connected to the power supply line 7, and the 100V tap 10b is connected to one fixed contact piece 1 of the tap changeover switch 13.
3a, and the 200V tap 10c is connected to the other fixed contact piece 13b of the tap changeover switch 13, and is also connected to the power supply line 14. Note that the movable contact piece C of the tap changeover switch 13 is connected to the power supply line 5. 15 is a fan motor rated at 200V, which is an electrical component that drives a fan (not shown) that cools the magnetron, which will be described later; 16 is an interior light rated at 200V, which is an electrical component disposed inside the range body; These fan motors 1
5 and the interior light 16 are connected between power lines 14 and 7. Reference numeral 17 is a heater rated at 200V disposed inside the microwave main body, 18a is a normally open contact of the oven cooking relay 18, and a series circuit between the normally open contact 18a as a selection switch and the heater 17 is connected to the power line 14. , 7. Reference numeral 19 denotes a heater circuit shutoff relay rated at 200 cm, and its excitation coil 19C is connected in parallel to the heater 17.

On the other hand, in the secondary coil 11 of the high voltage transformer 9, one terminal is connected to the iron core and the anode of the magnetron 20 and is grounded, and the other terminal is connected to one terminal of the heater of the magnetron 20 via the high voltage capacitor 21. Furthermore, a high voltage rectifier 22 is connected in parallel to the series circuit of the secondary coil 11 and the high voltage capacitor 21.
are connected, thereby forming a high voltage circuit 23. Both terminals of the secondary coil 12 have a normally closed contact 19b, which is a switch means of a heater circuit cutoff relay 19, on one side.
The heater circuit 24 is connected to both terminals of the heater of the magnetron 20 via the heater circuit 24 .

Now, 25 is a control device including a microcomputer 26, and each of its output terminals is connected to the relay 4.
and 18 excitation coils 4C and 18C are connected. Reference numeral 27 denotes a control power transformer, which includes a primary coil 28 and a secondary coil 29 having an intermediate tap 28a. The primary coil 2 of this control power transformer 27
8, one terminal thereof is connected to the other terminal of the power plug 1, the intermediate tap 28a is connected to one fixed contact piece 30a of the tap changeover switch 30, and the other terminal is connected to the other fixed contact piece 30a of the tap changeover switch 30. It is connected to the contact piece 30b. Further, both terminals of the secondary coil 29 are connected to the control device 2.
It is connected to the power terminal of 5. The movable contact piece 30c of the tap changeover switch 30 is connected to a common connection between the fuse 2 and the first door switch 3. This tap changeover switch 30 is adapted to be switched in conjunction with the tap changeover switch 13. As is well known, the control device 25 includes a control power transformer 27.
A constant DC voltage is obtained from the AC voltage induced in the secondary coil 29, and when the range key (not shown) is pressed, the excitation coil 4C of the power relay 4 is activated for a set time. energize the oven key (not shown)
When suppressed, the excitation coil 4C of the power supply relay 4 and the excitation coil 18C of the oven cooking relay 18 are both connected for a set time.

Next, the operation of this embodiment will be explained.

First, when connecting the power plug 1 to a 100V power outlet, press the tap changeover switches 13 and 30.
Turn on the contact pieces between 13 cm 13a and 30 cm 30a. Then, when the range key is suppressed, the excitation filter 4C is energized for the time set by the control device 25, so the power supply relay 4 is operated and the normally open contact 4a is turned on.
Turn on. As a result, 100
A commercial power supply voltage of v is applied. This 100V commercial power supply voltage is applied to the contact piece 13cm13a of the tap changeover switch 13.
One of the primary coils 10 in the high voltage transformer 9 through the
00v tap 10b and OV terminal 1. Oa, the primary coil 10 acts as a single-turn transformer, and an AC voltage of 200v is generated between the 200v tap 10c and the OV terminal 10a, which is applied to the power line 14.
, 7. Therefore, the fan motor 15 rated at 200V and the interior light 16 are energized and operate normally.

Also, since the voltage between both terminals of the primary coil 10 is 200V, a predetermined high voltage AC voltage (
A predetermined low-voltage AC voltage (3 to 4 V) is induced in the secondary coil 12, and the magnetron 20 is operated to perform high-frequency heating cooking.

Furthermore, in the case described above, when the oven key is depressed, the excitation coils 4C and 18C are energized for the time set by the control device 25, so that the power relay 4 and the oven cooking relay 18 are pressed. And always rJ
Turn on the n-contacts 4a and 18a. As a result, an AC voltage of 200V is applied between the power lines 14.7 in the same manner as described above, and the fan motor 15 and the interior light 16 are operated, and the heater 17 is energized via the normally open contact 18a. The oven operates to generate heat, and then oven cooking is performed. When the heater 17 is energized, the excitation coil 19C connected in parallel to the heater 17 is also energized, so the heater circuit cutoff relay 19 operates to turn off the normally closed contact 19b. Therefore, even if a predetermined AC voltage is induced in the secondary coils 11, 12 of the high voltage transformer 9, the heater circuit 24 of the magnetron 20 is turned off by the normally closed contact 19b, so the magnetron 20 does not operate.

When connecting the power plug 1 to a 200V power outlet, the contact pieces 13cm13b and 30cm30b of the tap changeover switches 13 and 30 are turned on. Therefore, when the normally open contact 4a is turned on, a commercial power supply voltage of 200V is applied between the power supply lines 5 and 7, and this 200V is applied to the primary coil 10 of the high voltage transformer 9 through the contacts 13cm and 13b of the tap changeover switch 13. tap 10
c, when applied between QV terminal 10a, power supply line 1
It is also applied between 4 and 7. As a result, in the same manner as described above, when the microwave key is depressed, high-frequency cooking is performed by the magnetron 20, and when the oven key is depressed, oven cooking is performed by the heater 17. During oven cooking, the normally closed contact 19b is turned off and the heater circuit 24 of the magnetron 20 is turned off.
Begins to cut.

As described above, according to this embodiment, the power supply voltage is 10OV, 2OV,
00V, the configuration is such that it is handled by switching the taps of the primary coil 10 of the high voltage transformer 9 without using a power supply transformer, when the heater 17 is energized to perform oven cooking, the heater circuit Since the shield relay 19 is operated and the heater circuit 24 of the magnetron 20 is cut off by its normally closed contact 19b, the magnetron 20 does not operate unnecessarily during oven cooking, unlike the conventional method.

By the way, it is possible to provide the normally closed contact 19b of the relay 19 in the high voltage circuit 23 of the magnetron 20, but if this is done, the normally closed contact 19b will cut off the high voltage AC voltage of 2000 V or more, so there will be no arc. is generated and acts on the microcomputer 26 as noise, which may cause the microcomputer 26 to malfunction.

In this regard, in this embodiment, the normally closed contact 19b provides 3 to 4V.
Since the low-voltage AC voltage heater circuit 24 is turned off, no noise is generated and the microcomputer 26 does not malfunction.

In the above embodiment, the excitation coil 19C of the relay 19 is connected in parallel to the heater 17, but for example, the excitation coil 19C may be connected between the power lines 14 and 7 through the normally closed contact of the relay 18 in series. In this case, the normally closed contact 19b of the relay 19 is replaced with a normally open contact serving as a switch means.

Further, in the above embodiment, the heater circuit 24 is provided with the normally closed contact 19b of the relay 19 as a switch means.
In short, it is sufficient to provide a switch means that turns off when the normally open contact 18a is turned on, that is, when the heater 17 is energized.

Further, in the above embodiment, the control device 25 including the microcomputer 26 is provided, but a mechanical timer using a timer motor as a driving source may be provided instead.
In this case, the relay 19 is provided with another normally closed contact in addition to the normally closed contact 19b, and this normally closed contact is used to connect the high voltage circuit 23.
You may also cut it.

Further, in the above embodiment, the fan motor 15. Interior light 16.
Although the heater 17 and relay 19 are rated at 200V, if they are rated at 100V, the power line 14 may be connected to the 100V tap 10b of the primary coil 10.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings; for example, the commercial power supply voltage is 100V.
, 200V, etc. It goes without saying that the present invention can be modified and implemented as appropriate without departing from the scope of the invention, such as being similarly applicable to cases where the voltage is different than 200V.

[Effects of the Invention] As explained above, in the microwave oven of the present invention, the magnetron heater circuit is cut off when the heater for oven cooking is energized. By changing the tap of
Even if the FA′#A pressure is different, the magnetron does not operate unnecessarily during oven cooking using a heater, which is an excellent effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical circuit diagram showing an embodiment of the present invention. In the figure, 4 is a power supply relay, 9 is a high voltage transformer, 10 is a primary coil, 10a is an Ov terminal, 10b is a 100V tap, 10C is a 200V tap, 11 and 12 are secondary coils, and 13 is a tap changeover switch. , 15 is a fan motor (electrical parts), 16 is an interior light (electrical parts), 17 is a heater, 18 is a relay for oven cooking, 18a is a normally open contact (selection switch), 19 is a relay for heater circuit shutoff, 19b is a normally 20 is a magnetron, 24 is a heater circuit, 25 is a control device, and 26 is a microcomputer. Applicant: Toshiba Corporation

Claims (1)

[Claims] 1. A predetermined electric component and a heater connected in series with a selection switch are connected to the primary coil side of the high-voltage transformer, and a magnetron is connected to the secondary coil side, and the taps of the primary coil are switched for different power supply voltages. Accordingly, a rated voltage is applied to the electric component and the heater via the selection switch, and a switch means is provided to turn off the heater circuit of the magnetron when the heater is energized by the selection switch. Microwave oven featuring.