JPH03168523A - Heating cooking oven - Google Patents

Abstract

PURPOSE:To use both 100V and 200V power sources in an electric cooking oven with an oven function by switching two electric heaters to series or parallel connection, and connecting a drive motor in parallel with one heater. CONSTITUTION:Power source voltage information Sv is judged by a controller 17, contacts 14a-14c of a connection switching switch 14 are turned OFF by a switching motor 22, contacts 14a-14d are turned ON at the time of using 200V to connect both electric heaters 12, 13 in series. Since the impedances of the heaters 12, 13 are substantially equal, about 100V is applied to a drive motor 15 connected in parallel with the heater 12. Since the impedances of the motors are sufficiently high, the composite impedance of the parallel circuit is substantially equal to that of the sole heater 12. The total power consumptions of both the heaters in both the 100V and 200V power sources are equal, and input powers of the motors become equal.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention is directed to a 100-120V power supply and a 200-240V power supply.
The present invention relates to a heating cooker that can be used with any system power source.

(Prior art) Commercial power supply voltage is mainly IOOV in Japan, but
00V is also becoming popular, and 100V and 200V are also becoming popular in other countries.
Some countries use either V or both, and the power supply voltage is not constant. Therefore, it would be convenient to have an electric cooker that can be used with any power supply voltage.

In this case, in order to be able to use an electric cooker with an oven function, such as an electric oven, with both IOOV and 200V power supply voltages, a switching power supply is provided, and this switching power supply is used for the electric heater and hot air blower. It has been considered to adjust the human power voltage to the drive motor of the fan device.

(Problems to be Solved by the Invention) However, when a switching power supply is provided as in the above configuration, there is a drawback that the electric circuit becomes complicated and costs increase.

The present invention was made in consideration of these circumstances, and its purpose is to provide convenience and low cost by being able to be used with both 100-120V power supplies and 200-240V power supplies with simple measures. The purpose of the present invention is to provide an IJ[1-covered cooking device that can be used at the same time.

[Structure of the Invention (Means for Solving the Problems) The cooking device of the present invention includes two electric heaters having substantially equal impedance, and air heated by these two electric heaters being sent into a cooking chamber. a fan device for heating food to be cooked; a connection switching circuit is provided for selectively switching both the electric heaters between series connection and parallel connection; and a drive motor of the fan device is connected in parallel to one of the electric heaters. This was a deliberate structure.

(Function) When using with a 100V power source, switch the connection switching circuit so that both electric heaters are connected in parallel. As a result, the human power voltage of each electric heater becomes 100V, and since the drive motor of the fan device is also connected in parallel to one of the electric heaters, the human power voltage of this drive motor is also 100V.
becomes.

On the other hand, when using with a 20OV power source, the connection switching circuit is switched so that both electric heaters are connected in series. In this case, since the impedances of both electric heaters are set to be substantially equal, the power supply voltage of 200V is divided into approximately 100V by both electric heaters. As a result, a voltage of approximately 100V is applied to each electric heater, and a voltage of approximately 100V is also applied to the drive motor connected in parallel with one of the electric heaters.

Note that since the impedance of the drive motor is sufficiently larger than that of the electric heater, the combined impedance of the parallel circuit of the drive motor and the electric heater is approximately equal to the impedance of the electric heater alone.

(Example) Hereinafter, an example in which the present invention is applied to a microwave oven with an oven function will be described based on the drawings.

1 is a power plug, one terminal of which is connected to one power terminal of a magnetron drive inverter circuit 6 through a fuse 2, a thermal switch 3, a first door switch 4, and an output switching relay switch 5 in series. has been done. Further, the other terminal of the power plug 1 is connected to the second door switch 7.
, is connected to the other power terminal of the magnetron drive inverter circuit 6 via a main relay switch 8 and a relay switch 9 for switching on current. In this case, although not shown, when the front door of the heating cooking chamber is opened, the first and second
The double-door switches 4 and 7 are turned off, blocking power supply to the magnetron drive inverter circuit 6, and the normally open short switch 1 connected between the double-door switches 4 and 7 is turned off.
0 is turned on to short-circuit both door switches 4 and 7.

On the other hand, the energization switching relay switch 9 has one movable contact 9a and two fixed contacts 9b, 9c, and one fixed contact 9c side is connected to the magnetron drive inverter circuit 6 described above. A connection switching circuit 1 is provided between the other fixed contact 9b and the power line 1a of the five output switching relay switches. This connection switching circuit 11 selectively switches the two electric heaters 12, 1B between series connection and parallel connection, and specifically has the following structure. That is, the fixed contact 9b of the energization changeover relay switch 9 and the fixed contact 1. of the connection changeover switch 14. 4d, two electric heaters 12.1B are connected in series, and the drive motor 15 of the fan device 24 (see Fig. 4) is connected in parallel to one of the electric heaters 12. Fourteen fixed contacts 14e are connected to a common connection point between both electric heaters 12 and 13.

The movable contact 14a of the connection changeover switch 14 is connected to the fixed contact 9b side of the energization switching relay switch 9, and the fixed contact 14c corresponding to the movable contact 14a is shared with the fixed contact 14d. In addition, the fixed contact 14
A movable contact 14b that switches between d and 14e is connected to the power line 1a on the output switching relay switch 5 side.

In this case, both electric heaters 12 and 13 are set to have substantially the same impedance so that their power consumption is substantially equal when the same voltage is applied, and as shown in FIG.
It is shaped like an annular ring surrounding four fans 25. The electric heaters 12 and 13 and the fan device 24 are arranged at the back of a heating cooking chamber (not shown), and they blow hot air into the heating cooking chamber to heat the food.

On the other hand, a control circuit 17 that controls microwave heating and oven IJ mouth heat is supplied with power via an inverter power circuit 18 connected between both power lines la and lb. Furthermore, from this inverter power supply circuit 18, information Sv of the commercial power supply voltage is transmitted.
is manually input to the control circuit 17. Based on the output of the control circuit 17, the drive coils 19, 20, and 21 of the main relay switch 8, the output switching relay switch 5, and the energization switching relay switch 9 are energized and disconnected. 8. Controls on/off of the output switching relay switch 5, and switches the movable contact 9a of the energization switching relay switch 9 between the fixed contacts 9b and 9c. In this case, when heating in a microwave, the energization switching relay switch 9 is turned on between contacts 9a to 9c, and the magnetron drive inverter circuit 6 causes the magnetron 16 to oscillate. On the other hand, when heating the oven, connect the rtE switching relay switch 9.
9A to 9B, the power is turned on to energize both electric heaters 12, 3, and the drive motor 15 of the fan device 24.

In addition, both movable contacts 14a, 14 of the connection changeover switch] 4
The switching operation b is performed by a switching motor 22, and the operation of this switching motor 22 is controlled by a control circuit 17.

Although not shown, various operation keys are provided on the front operation panel of the microwave oven, and operation signals from the operation keys are input to the control circuit 17 to switch between microwave heating and oven heating, and to control heating. Setting of time, etc. is performed.

Next, the above-mentioned alerting effect will be explained.

When the power supply plug 1 is inserted into a power outlet (not shown), the inverter power supply circuit 18 starts operating and supplies power to the control circuit 17, and the inverter power supply circuit 18 starts operating.
Information S on the commercial power supply voltage is manually inputted to the control circuit 17, and the power supply voltage is determined.

At this time, if the power supply voltage is 200V, the connection switching circuit 11 is automatically switched so that both electric heaters 12 and 13 are connected in series. This switching is performed by operating the control circuit 17 or the switching motor 22 to turn off the contacts 14a-14c of the connection changeover switch 14 and turn on the contacts 14b-14d, as shown in FIG. It will be done. If both electric heaters 12 and 13 are switched to be connected in series in this way, the impedance of both electric heaters 12 and 13 is set approximately equal, so the power supply voltage of 200V is changed to approximately 100V by both electric heaters 12 and 13. Partial pressure is applied. As a result, a voltage of approximately 100V is applied to each of the electric heaters 12 and 13, and a voltage of approximately 100V is also applied to the drive motor 15 connected in parallel to one of the electric heaters 12.

Note that the impedance of the drive motor 15 is the same as that of the electric heater 1.
This drive motor 1 is sufficiently large compared to that of drive motor 2.
The combined impedance of the parallel circuit of the electric heater 12 and the electric heater 12 is approximately equal to the impedance of the electric heater 12 alone.

Here, is it the commercial power supply voltage or both when it is 200V? The total power consumption P of the a-air heaters 12 and 13 is 20 nV because the impedance R of both electric heaters 12 and 13 is the same. On the other hand, if the power supply voltage is 100 V, the connection switching circuit 11
are automatically switched so that both electric heaters 1.2.13 are connected in parallel. This switching is performed by the control circuit 17 operating the switching motor 22, as shown in FIG. This is done by turning on between contacts 4a and 14c and turning on between contacts 14b and 14e. In this way, both electric heaters 12,
13 to be connected in parallel, the input voltage of each electric heater becomes 100V with respect to the power supply voltage of IOOV, and the drive motor 15 of the fan device 24 also connects one electric heater 12.
Since the drive motor 15 is connected in parallel, the human power voltage of this drive motor 15 is also 100V. In this case, both electric heaters 12
, 13 total power consumption Pl. OOV is both electric heaters 1
Since the impedances R of 2 and 13 are the same, the above (1). As is clear from equation (2), whether the power supply voltage is IOOV or 200V, the total power consumption of both electric heaters 12 and 13 is equal, and moreover, the human power of the drive motor 15 of the fan device 24 is also Therefore, the temperature and air volume of the hot air supplied into the heating cooking chamber can be made equal, and the electric voltage is IOOV, 2. You can cook in the same way with either OOV.

In the above embodiment, the control circuit 17 determines the power supply voltage based on the information Sv from the inverter power supply circuit 18,
Since the connection changeover switch 14 of the connection changeover circuit 11 is automatically changed over, there is no need for the user to perform any changeover operation, making it extremely easy to use.Moreover, the changeover can be performed reliably (no human intervention required). However, the present invention may be configured such that the connection changeover switch 14 of the connection changeover circuit 11 is manually operated, and even in this case, the intended purpose of the present invention can be sufficiently achieved. can.

In addition, the present invention can be modified in various ways, such as being applicable to an electric oven without a range heating function.

[Structure of the Invention] As is clear from the above description, the present invention provides a connection switching circuit that selectively switches two electric heaters having substantially equal impedance between series connection and parallel connection, and also provides a connection switching circuit that selectively switches two electric heaters having substantially equal impedance between series connection and parallel connection. Since the motor is connected in parallel to one electric heater, the commercial power supply is 100-120V, 2
Regardless of the 00 to 240 V system, the total power consumption of both electric heaters is equal, and the input power of the drive motor of the fan device is also equal. Therefore, regardless of the power supply voltage, the temperature and volume of the hot air supplied into the cooking chamber can be made equal, and cooking can be performed in the same way.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is an overall electrical circuit diagram, Fig. 2 is an electrical circuit diagram showing the switching state of a connection selector switch in the case of a 200V power supply, and Fig. 0
FIG. 4 is an electric circuit diagram showing the switching state of the connection changeover switch in the case of a 0V power source, and FIG. 4 is a perspective view of both electric heaters and a fan device. In the drawing, 1 is a power plug, 4 is a first door switch, 5 is an output switching switch, 6 is an inverter circuit for driving the magnetron, 7 is a second door switch, 8 is a main relay switch, and 9 is for energization switching. Relay switch, 10 is a short switch, 1l is a connection switching circuit, 12 and 13 are electric heaters, 14 is a connection switching switch, 15 is a drive motor, 1
6 is a magnetron, 17 is a control circuit, 18 is an inverter power supply circuit, 22 is a switching motor, 24 is a fan device, 2
5 is a fan.

Claims (1)

[Claims] 1. Equipped with two electric heaters with substantially equal impedance and a fan device that sends air heated by these electric heaters into a cooking chamber to heat the food, and connects both electric heaters in series and in parallel. 1. A heating cooking device characterized in that a connection switching circuit is provided for selectively switching between the two electric heaters, and the drive motor of the fan device is connected in parallel to one of the electric heaters.