JPS63193475A - Heating cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a heating cooker such as an open toaster.

(b) Prior art For example, the prior art is Utility Application No. 61-743 filed by the applicant of the present application.
As shown in No. 06, the relay coil has transistors, which are semiconductor switching elements controlled by a timer circuit, connected in one row, so when the power outlet is connected and the start switch is not activated, If this transistor fails and becomes short-circuited, the relay coil will keep the relay switch connected in series with the heater open, and as a result, the heater will continue to be energized even though the user has no intention of using it. This could lead to abnormal heating.

(c) Problems to be Solved by the Invention Therefore, the present invention provides a heating cooker that prevents the heater from being inadvertently energized when the power source is inserted into a power socket receptacle embedded in a wall or the like. There is a particular thing.

(d) Means for Solving the Problems The present invention provides a method in which a second semiconductor switching element such as a thyristor is connected in series with a first semiconductor switching element such as a transistor that controls the operation of a relay coil that controls energization of a heater. It has a configuration.

(E) Effect Even if there is a failure in either one of the semiconductor switching elements, the existence of the other semiconductor switching element prevents the relay coil from being inadvertently energized and causing the heater to heat up.

(F) Embodiment 1 is a power outlet that is connected to and detached from an outlet receptacle installed on a wall (not shown) to obtain AC power for household use. Reference numeral 2 denotes a heater, which is connected to the power outlet 1 via a normally open relay switch 3 with a coil, which will be described later.

The diode 4, the resistor 5, the capacitor 6, and the Zener diode 7 constitute a constant voltage circuit.

8 is a Bunonyu type start switch, which is normally closed. Reference numeral 9 denotes a relay coil, which, when energized, closes the interlocking relay switch 3 and enables the heater 2 to be energized.

IO is a first semiconductor switching element (hereinafter referred to as a transistor) such as a transistor connected in series to the relay coil 9. Reference numeral 11 denotes a second semiconductor switching element such as a thyristor (hereinafter referred to as a thyristor) connected in series to the transistor 10.

Therefore, when the start switch 8 is pressed, the resistor 13,
A voltage is applied to the base of the transistor 100 through the diode 14 and the resistor 15, and the transistor 10 is turned on. Moreover, at the same time as the transistor 10 is turned on by pressing the start switch 8, a voltage is applied to the gate of the thyristor 11 to make the thyristor 11 conductive. Therefore, the relay coil 9 is energized, closes the relay switch 3, and heats the heater 2.

The diode 18, the resistor 19, the capacitor 20, and the Zener diode 21 form a constant voltage circuit.

Further, since the voltage is applied to the base of the transistor 10 through the variable resistor 23, the diode 24, and the resistor 25, the transistor 10 remains on even if the start switch 8 returns to the open state.

Similarly, when the gate of the thyristor 11 is applied and the thyristor 11 becomes conductive, it remains ON even if the start switch 8 is in the open state.
′+: #I have it. Therefore, the relay coil 9 maintains a conductive state and heats the heater 2. The resistor 27 is used to protect the thyristor 11, and the capacitor 28 is used to prevent the thyristor 11 from malfunctioning.

Then, the heater 2 conducts electricity and heats the capacitor 3.
0 is gradually charged, and when a predetermined value is reached, the PUT 31 becomes conductive, thereby cutting off the current flowing to the transistor 10 through the variable resistor 23, the diode 24, and the resistor 25. Therefore, the transistor 10 is turned off, and the heater 2 The power supply to is cut off.

After that, the capacitor 30 is gradually discharged, and when the heater 2 is heated by electricity, the time for full charging of the capacitor 30 is shortened, and the conduction time of the PUT 31 is also shortened, and as a result, the transistor 10 is also charged quickly. The power supply to the heater 2 is cut off before the food to be cooked becomes scorched. This capacitor 30 corrects the continuous heating time.

According to such a configuration, the transistor 10 and the thyristor 11
The probability that both will fail at the same time and become energized is approximately IQ-14.
As described below, when the power outlet 1 is plugged in and the start switch 8 is not pressed, the relay coil 9 is energized and the heater 2 is almost never heated up inadvertently, and the transistor 10 or thyristor 11 is When there is only one, the probability that each of these will fail is about 10.

(G) Effects of the Invention Since the present invention has the above-mentioned configuration, it eliminates abnormal heating such as dry cooking caused by inadvertently energizing the heater due to a failure of the semiconductor switching element when the power outlet is plugged in. It is something that will be done.

[Brief explanation of the drawing]

The drawing is an electric circuit diagram of the cooking device of the present invention. 2... Heater 3... Relay switch 8... Start switch 9... Relay coil 10... First semiconductor switching element 11... Second semiconductor switching element

Claims (1)

[Claims] (1) A heating heater supplied with power via a power outlet, a relay switch connected in series to the heater and opened and closed by a relay coil, and a first transistor or the like that controls energization to the relay coil. A semiconductor switching element, a timer for controlling energization of the first semiconductor switching element, and a second semiconductor switching element such as a thyristor operated by a start switch and connected in series with the first semiconductor switching element. A heating cooker with special features.