KR20000009623A - Circuit for reducing noises of microwave oven - Google Patents

Abstract

PURPOSE: A circuit for reducing noises of microwave oven controls a driving of a fan motor with a low noise after completing a cooking operation of a microwave oven, and removes moisture inside of a cooking chamber. CONSTITUTION: A noise reduction circuit of a microwave oven includes first and second AC lines(L1,L2) whose one end are connected to an input terminal of the AC power, and the other end are connected to a high voltage transformer(HVT) via a door switch(SW1,SW2), a monitor switch, a main relay(RY1), and a power relay(RY2). The noise reduction circuit further includes a lamp(L) and fan motor(FM) which are turned on or off by a main relay. The noise reduction circuit includes a fan motor driver(10) for independently driving the fan motor about the lamp and each load. A microcomputer(11) controls an on/off operation of the fan motor driver. Thereby, a unnecessary power-consumption is prevented, and a reliability of the product.

Description

Microwave Noise Reduction Circuit

The present invention relates to a noise reduction circuit of a microwave oven, and more particularly, to a noise reduction circuit of a microwave oven to remove moisture in a cooking chamber by controlling the driving of a fan motor after the completion of cooking of the microwave oven.

In general, a microwave oven is a device for heating / cooking food using microwaves. The microwave oven is composed of a general high voltage transformer and a magnetron. The high voltage transformer generates a predetermined high voltage to drive the magnetron. The magnetron emits microwaves of high frequency (approximately 2450 MHz) in a confined space where food is stored. Microwaves emitted in this way vibrate the water molecules contained in the food, molecular friction heat is generated in accordance with the vibration of the water molecules is to heat / cook food.

1 is a partially cutaway exploded perspective view illustrating a conventional microwave oven, and FIG. 2 is a circuit diagram of FIG. 1.

According to Figure 1, the cabinet 20 forming the appearance of the microwave oven is divided into a left and right space is provided with a cooking chamber 22, the front of which is open on one side, the lamp (L), fan motor (FM), magnetron on the other side The apparatus room 23 in which various electric appliances, such as (MGT), a high voltage transformer (HVT), and a high voltage capacitor (HVC), is installed is provided. In addition, an air guide 26 is provided at one side of the cabinet 20 in the apparatus chamber 23 to guide the air blown from the fan motor FM into the cooking chamber 22, and the apparatus chamber 23 is provided. An operation panel 25 is provided on the front surface to operate the microwave and to display the state thereof.

In addition, the door 21 that opens and closes the front of the cooking chamber 22 is rotatably fixed to one side of the cabinet 20, and the rotating dish 24 in which food to be cooked is placed in the bottom surface of the cooking chamber 22. ) Is installed, the rotary dish 24 is rotated by a drive motor and gears not shown in the bottom surface of the cabinet 20 during food cooking to increase the cooking efficiency.

2, one end of the first and second commercial AC lines L1 and L2 is connected to the noise filter 1 on the input side to input a normal commercial AC power supply AC 110V or 220V. The ends are connected to both ends of the high voltage transformer (HVT) primary coil. Although the noise filter 1 is not illustrated in the drawings, the noise filter 1 is the same as a conventional noise filter including components such as a fuse, a capacitor, an inductor, and a resistor, and thus a detailed description thereof will be omitted.

In addition, a main relay RY1, a first door switch SW1, and a monitor switch SW3 are connected to the first commercial AC line L1, and a power relay RY2 to the second commercial AC line L2. And second door switch SW2 are respectively connected. In addition, a lamp L and a fan motor FM are connected between the first commercial AC line L1 and the second commercial AC line L2.

The main relay RY1 controls driving states of the lamp L and the fan motor FM, and the power relay RY2 applies a commercial AC power to the primary coil of the high voltage transformer HVT. . The first to second door switches SW1 and SW2 and the monitor switch SW2 are turned on / off according to the opening / closing state of the door 21 to perform a safety function of the microwave oven.

In addition, a magnetron (MGT), a high voltage capacitor (HVC), and a high voltage diode (HVD) for generating microwaves are provided on the secondary coil side of the high voltage transformer (HVT).

In addition, a microcomputer 2 for detecting an open / closed state of the door through the monitor switch SW3 and controlling an on / off operation of the main relay RY1 and the power relay RY2 is provided.

In addition, a key input unit 3 for inputting a user's command to the microcomputer 2 and a display unit 4 for displaying various operating states of the microwave under the control of the microcomputer 2 are provided. (2), the key input section 3 and the display section 4 are preferably arranged on the operation panel 25 shown in FIG.

Looking at the operation of the conventional microwave oven configured as described above are as follows.

First, the user opens the door 21 and places the food on the top of the rotating dish 24 inside the cooking chamber 22 through the front of the cabinet 20 in the state in which the cooking chamber 22 is opened. Subsequently, when the door 21 is closed, the door switch SW1 (SW2) and the monitor switch SW3 are turned on, and in this state, the user can change the amount and type of food through the key input unit 3 of the operation panel 25. Set / input cooking time and temperature accordingly.

Accordingly, the microcomputer 2 detects the state in which the door 21 is closed through the monitor switch SW3, turns on the main relay RY1 and the power relay RY2, and sets / inputs in the key input unit 3. The microwave oven in the closed state.

When the operation of the microwave is started as described above, the commercial AC power inputted through the first and second commercial AC lines L1 and L2 is performed by the respective door switches SW1 and SW2 and the monitor switch SW3. ), The main relay RY1 and the power relay RY2 are supplied to the primary coil of the high voltage transformer HVT to drive the high voltage transformer HVT.

In addition, a commercial AC power supply is also supplied to the lamp L and the fan motor FM so that the lamp L illuminates the inside of the cooking chamber 22, and the fan motor FM is located in the apparatus chamber 23. In addition to cooling various circuit components, the heated air is blown into the cooking chamber 22 through the magnetron (MGT) and the air guide 26.

In addition, the high voltage transformer (HVT) supplies a high voltage to the magnetron (MGT) through the secondary coil, the magnetron (MGT) generates a microwave to release the inside of the cooking chamber 22 to the desired food and When heating / cooking to a temperature and cooking is completed, the microcomputer 2 turns off the main relay RY1 and the power relay RY2 described above. On the other hand, when the cooking operation is completed as described above, the microcomputer 2 turns on only the main relay RY1 again for a predetermined time to drive the fan motor FM to remove moisture in the cooking chamber 22.

However, in the conventional microwave oven, when only the main relay is turned on to remove moisture in the cooking chamber as described above, a lamp is turned on together with the fan motor, and unnecessary power is consumed, and the rotation of the fan motor is performed. According to this there was a problem that noise occurs even after the cooking is finished.

In addition, even after the cooking is completed as described above, due to the noise of the fan motor for removing moisture and the lighting of the lamp, the user may not know the correct operation state according to the cooking state of the microwave oven or the moisture removal state, and thus the reliability of the product is improved. There were other problems that deteriorated.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, after the cooking of the microwave oven to operate only the fan motor separately, controlling the drive of the fan motor to low noise to control the moisture inside the cooking chamber It is to provide a noise reduction circuit of the microwave oven to remove.

1 is an exploded perspective view showing main parts of a conventional microwave oven;

2 is a circuit diagram of FIG.

3 is a circuit diagram showing a preferred embodiment of the microwave noise reduction circuit according to the present invention.

Explanation of symbols on the main parts of the drawings

10: fan motor drive unit 11: microcomputer

FM: Fan Motor L: Lamp

HVT: High voltage transformer L1, L2: Commercial exchange line

SW1, SW2: Door switch SW3: Monitor switch

RY1: main relay RY2: power relay

RY10: Fan relay R10: Current limiting resistor

A characteristic of the noise reduction circuit of the microwave oven according to the present invention for achieving this object is that one end thereof is connected to the input side of a commercial AC power supply, and a high pressure is applied to the other end via a door switch, a monitor switch, a main relay and a power relay. A microwave oven comprising a lamp and a fan motor connected between a first and a second commercial exchange line to which a transformer is connected and the first and second commercial exchange lines are turned on and off by the main relay. And a fan motor driving unit for driving the motor independently with respect to the lamp and various loads, and a microcomputer controlling on / off operation of the fan motor driving unit.

The fan motor driver includes a fan relay connected to one side of the first commercial AC line and a current limiting resistor connected to one side of the fan relay and the other end connected to a power input side of the fan motor.

The microcomputer preferably turns off the main relay and the power relay after the cooking is finished, and turns on the fan relay for a predetermined time to remove moisture in the cooking chamber.

Therefore, only the fan motor is operated separately after the cooking of the microwave oven, and the fan motor is controlled at low rotation / low noise through a current limiting resistor to remove moisture in the cooking chamber, thereby preventing noise and unnecessary power consumption. And improve the reliability of the product.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the noise reduction circuit of the microwave oven according to the present invention, the same components as in the prior art will be described by applying the same reference numerals.

3 is a circuit diagram showing a preferred embodiment of the microwave noise reduction circuit according to the present invention.

Accordingly, one end thereof is connected to the input side of the commercial AC power supply, and the first to second door switches SW1 and SW2, the monitor switch SW3, the main relay RY1 and the power relay RY2 are connected to each other. It is connected between the first and second commercial AC (L1) (L2) and the first and second commercial AC (L1) (L2) connected to the other end of the high voltage transformer (HVT) at the other end of the main Having the lamp L and the fan motor FM turned on / off by the relay RY1 is similar to the configuration described through the prior art.

However, the main features of the present invention, as shown, the fan motor driving unit 10 and the fan motor driving unit 10 to independently drive the fan motor (FM) with respect to the lamp (L) and various loads The microcomputer 11 for controlling the on / off operation of is further provided.

Here, the fan motor driver 10 includes a fan relay RY10 and a current limiting resistor R10, and the fan relay RY10 is connected to one side of the first commercial AC line L1, and the current The limiting resistor R10 has one side connected to the fan relay RY10 and the other side connected to the power input side of the fan motor FM.

In addition, the microcomputer 11 turns off the main relay RY1 and the power relay RY3 after the cooking is finished, and turns on the fan relay RY10 for a predetermined time to remove moisture in the cooking chamber 22. Do it.

If described in more detail the action of the preferred embodiment according to the present invention configured as follows.

According to the user's operation, the microcomputer 11 turns on the main relay RY1 and the power relay RY2, and accordingly, the commercial AC power input through the first and second commercial AC lines L1 and L2. ) Is supplied to the primary coil of the high voltage transformer HVT through the respective door switch SW1, SW2, monitor switch SW3, main relay RY1, and power relay RY2. Is driven, the high voltage transformer (HVT) supplies a high voltage to the magnetron (MGT) through the secondary coil, the magnetron (MGT) generates a microwave to emit the food into the cooking chamber 22 inside the cooking chamber 22 After heating / cooking to a desired temperature and cooking is completed, the microcomputer 11 turns off the main relay RY1 and the power relay RY2 described above.

In the state in which the cooking operation is completed as described above, the microcomputer 11 turns on only the fan relay RY10 of the fan motor driving unit 10 for a predetermined time to rotate the fan motor FM at low speed so as to remove moisture in the cooking chamber 22. Remove it.

That is, as the fan relay RY10 is turned on, the commercial AC power input through the first commercial AC line L1 is decompressed through the current limiting resistor R10 and supplied to the fan motor FM. do. Therefore, the fan motor FM is rotated at a low speed by the current limiting resistor R10, and thus the noise is extremely reduced. In addition, since the power is not supplied to the lamp L and other loads, unnecessary power consumption is prevented, and the user can easily determine the operating state or the moisture removal state of the microwave oven.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes are intended to fall within the scope of the claims set forth.

As described above, according to the noise reduction circuit of the microwave oven according to the present invention, after the cooking of the microwave is operated only the fan motor separately, the drive of the fan motor at low rotation / low noise through the current limiting resistor By controlling to remove moisture in the cooking chamber, there is an effect of preventing noise and unnecessary power consumption and improving the reliability of the product.

Claims (3)

First and second commercial AC lines, one end of which is connected to an input side of a commercial AC power supply, a high voltage transformer connected to the other end via a door switch, a monitor switch, a main relay, and a power relay; In the microwave oven having a lamp and a fan motor connected between the commercial alternating line on / off by the main relay, A fan motor driver configured to independently drive the fan motor with respect to the lamp and various loads; And And a microcomputer for controlling the on / off operation of the fan motor driving unit. According to claim 1, wherein the fan motor drive unit, A fan relay connected to one side of the first commercial exchange line; And Noise reduction circuit of the microwave oven, characterized in that the one side is connected to the fan relay and the other side is a current limiting resistor connected to the power input side of the fan motor. The method of claim 2, wherein the microcomputer, And turning off the main relay and the power relay after the cooking is finished, and turning on the fan relay for a predetermined time to remove moisture in the cooking chamber.