KR19990049629A - microwave - Google Patents

Abstract

The present invention relates to a microwave oven in which a safety function is added to prevent the magnetron from oscillating continuously during a malfunction (short circuit) of a power relay that controls the output of the microwave oven in a microwave oven having a plurality of magnetrons.

The configuration is that the first oscillation circuit portion for oscillating the first magnetron and the second oscillation circuit portion for oscillating the second magnetron are connected in parallel with respect to the power supply stage, and the first and second oscillation circuit portions are connected to the first and second oscillation circuit portions. First and second power relays for controlling the output of the first and second magnetrons by controlling the first and second high voltage parts for supplying the oscillation power to the two magnetrons, and the power to the first and second high voltage parts. And a safety relay connected to a front end of the first and second power relays, the safety relays being connected to cut off power prior to the first and second power relays, and the first and second power relays and the safety relay. It is characterized in that the microcomputer is included to control the relay on / off.

Therefore, according to the present invention, it is possible to prevent the magnetron from continuously oscillating when the power relay controlling the output of the magnetron is malfunctioned (short circuit). Accordingly, it is possible to improve the operation reliability of the microwave oven.

Description

microwave

The present invention relates to a microwave oven, and more particularly, in a microwave oven having a plurality of magnetrons, a safety function for preventing the magnetron from continuously oscillating during a malfunction (short circuit) of a power relay that controls the output of the microwave is provided. To an added microwave oven.

FIG. 1 is an electrical connection diagram of a commercial microwave oven having two magnetrons for increasing the amount of high-frequency generation in the related art.

In the configuration, the first oscillation circuit portion 10 for oscillating the first magnetron 14 and the second oscillation circuit portion 20 for oscillating the second magnetron 24 are connected in parallel to the power supply terminal. In addition, the oscillation circuit units 10 and 20 interlock with the high voltage parts 15 and 25 for supplying the oscillation power to the magnetrons 14 and 24, and the power supply to the high voltage parts 15 and 25 in conjunction with the opening and closing of the microwave oven. Safety switches (11, 21), the magnetron (14, 24) of the thermal switch (TCO1, TCO2) and the microcomputer (not shown) Power relays 13 and 23 for controlling the output of the magnetrons 14 and 24 by controlling the power to the high voltage parts 15 and 25 by control, and the magnetrons 14 and 24 in the microwave oven door. Low voltage transformer (LVT) for supplying power to the main PCB and all the power devices, the first monitor switch 12 of the first oscillation circuit part 10, and the second oscillation. It is connected to the second monitor switch 22 of the circuit unit 20 and the monitor fuse (fuse3). The.

That is, the monitor circuit may include a low voltage transformer LVT connected to receive power regardless of the opening / closing operation of the first safety switch 11, and the first magnetron when the first safety switch 11 is turned on. A first monitor switch 12 switched to ab 11 and a circuit switched to the second monitor switch 22 when the first safety switch 11 is in an off operation; A second switch (fe) to the second magnetron 24 when the switch 22 is turned on, and a circuit switch fd to the first monitor switch 12 when the second safety switch 21 is turned off; A monitor fuse (fuse3) connected to the second monitor switch (22) and the second monitor switch (22) and connected to a power supply terminal. Therefore, the monitor circuit is connected to the low voltage transformer (L.V.T), the first monitor switch 12, the second monitor switch 22, and the monitor fuse (fuse3) to form a short circuit.

Accordingly, the safety switch 11, 21 of any one circuit part of the first oscillation circuit part 10 and the second oscillation circuit part 20 of the conventional microwave oven cuts the circuit in a state in which the door of the microwave oven is opened due to a defective contact. If this is not done, a short circuit is constructed so that the monitor fuse fuse3 is blown to cut off the power supply to the low voltage transformer LVT. Therefore, the microcomputer operating by being supplied with power by the low voltage transformer (L.V.T) also stops operating. When the microcomputer stops operating, the power relays 13 and 23 of the first oscillator circuit unit 10 and the second oscillator circuit unit 20 which are switched by the control of the microcomputer are turned off, and the high voltage unit 15 and 25 are turned off. The power supply to) is cut off, and the oscillation of the magnetrons 14 and 24 is also stopped.

However, the conventional microwave oven has the following problems.

That is, when the power relay is shorted in the microwave condition of the microwave oven, a closed circuit is formed from the power supply terminal to the magnetron, and the microwave is continuously operated. Therefore, there is a limit to improving the reliability of the microwave oven.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent the magnetron from continuously oscillating when a power relay for controlling the output of the microwave (short circuit) operates in a microwave oven having a plurality of magnetrons. It is to provide a microwave with a safety switch for.

1 is an electrical connection diagram of a conventional microwave oven,

2 is an electrical connection diagram of a microwave oven according to the present invention;

3 is a relay driving circuit applied to the present invention.

* Description of the symbols for the main parts of the drawings *

30: first oscillation circuit section 31: first safety switch 32: second monitor switch

33: 1st power switch 34: 1st magnetron 35: 1st high voltage part

40: first oscillation circuit part 41: second safety switch 42: second monitor switch

43: 2nd power switch 44: 2nd magnetron 45: 2nd high voltage part

46: Safety relay TCO: Thermo sensor

In order to achieve the above technical problem, a configuration of the present invention includes: a first oscillation circuit portion for oscillating a first magnetron and a second oscillation circuit portion for oscillating a second magnetron are connected in parallel to a power supply terminal, and the first, In the second oscillation circuit unit, the first and second high voltage parts for supplying the oscillation power to the first and second magnetrons, and the power supply to the first and second high voltage parts are interrupted to output the first and second magnetrons. In a microwave oven comprising a first and second power relay for controlling, and a microcomputer for controlling the output of the first magnet and the second magnetron by controlling the first and second power relay on / off, Connected to the front end of the first and second power relay, when the microcom outputs a control signal to turn on / off the first and second power relays, It characterized in that the relay is provided.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Commercial microwave ovens are equipped with at least two magnetrons to increase power. 2 illustrates such a commercial microwave oven (hereinafter referred to as a microwave oven) in accordance with the present invention.

2 is an electrical connection diagram of a microwave oven according to the present invention, the configuration of which is as follows.

The first oscillation circuit section 30 for oscillating the first magnetron 34 and the second oscillation circuit section 40 for oscillating the second magnetron 44 are connected in parallel with the power supply terminal, and the power supply terminal and the first A safety relay 46 is provided between the oscillation circuit section 30 and the parallel connection end of the second oscillation circuit section 40. In addition, the oscillation circuit parts 30 and 40 are connected to the high voltage parts 35 and 45 for supplying the oscillation power to the magnetrons 34 and 44 and the opening and closing of the microwave oven to supply power to the high voltage parts 35 and 45. Safety switch (31,41) for the control, and the thermoswitch (TCO3, TCO4) for controlling the power to the high voltage section (35, 45) when the magnetron (34, 44) is overheated, and microcomputer (not shown) The power relays 33 and 43 for controlling the output of the magnetrons 34 and 44 by controlling the power to the high voltage parts 35 and 45 by the control of the magnetron 34 and the magnetron 34, The low voltage transformer (LVT) for supplying power to the main PCB and the general power device, the first monitor switch 32 of the first oscillation circuit part 30, the second Connected to the second monitor switch 42 and the monitor fuse (fuse6) of the oscillation circuit portion 40 Prepared.

Opening and closing operation of the safety relay 46 of the above-described configuration is controlled by a microcomputer, as shown in FIG. That is, when the cooking signal is input from the outside, the microcomputer outputs a control signal for operating the safety relay 46. The switching element TR1 is switched by the control signal output from the microcomputer. At this time, a current is supplied to the relay drive coil. When a current is supplied to the relay drive coil, the relay drive coil is excited to close the contact point of the safety relay 46 to supply power to the microwave for the oscillation.

The monitor circuit includes a low voltage transformer (LVT) connected to receive power regardless of the opening / closing operation of the first safety switch 31, and the first magnetron at the time of the on operation of the first safety switch 31. 31) and the first monitor switch 32 and the second monitor switch 42, the circuit switch to the second monitor switch 42 in the off operation of the first safety switch 31, the on operation of the second safety switch 42 A second monitor switch 42 which is switched to the second magnetron 46, and which is switched to the first monitor switch 32 when the first safety switch 31 is turned off, and the second monitor switch It consists of monitor fuse (fuse6) connected to (42) and connected to the power supply terminal. In addition, the monitor circuit is circuit-connected so that power can be supplied from the power supply terminal regardless of the opening and closing operation of the safety relay 46.

Hereinafter, a safety function of the microwave oven according to the present invention will be described with reference to the above-described configuration.

When the power cord of the microwave oven is plugged into an outlet, the low voltage transformer (L.V.T) provided in the first oscillator circuit 30 supplies the power to the main P.C.B and the power device by appropriately reducing the input AC power. After that, when the consumer puts food into the cooking chamber and closes the door of the microwave oven, the first safety switch 31 of the first oscillation circuit part 30 and the second safety switch 41 of the second oscillation circuit part 40 are closed. Closes the circuit in conjunction with the closing of. At this time, the first monitor switch 32 of the first oscillation circuit portion 30 and the second monitor switch 42 of the second oscillation circuit portion 40 are linked with the closing of the door to open the short circuit and close the circuit ( gh, lk). When the cooking start signal is input to the microcomputer on the main PCB by the consumer, the microcomputer is the first power relay 33 of the first oscillation circuit part 30 and the second power relay 43 of the second oscillation circuit part 40, Then, the safety relay 46 is operated to supply power to the first high pressure part 35 and the second high pressure part 45. Accordingly, the microwave oven performs a cooking operation by oscillation of the first magnetron 34 and the second magnetron 44.

When the door of the microwave oven is opened while the cooking operation is performed, the first safety switch 31 of the first oscillation circuit unit 30 and the second safety switch 41 of the second oscillation circuit unit 40 open in conjunction with this. Power supply to the first and second magnetrons 34 and 44, and at the same time, the first monitor switch 32 of the first oscillation circuit part 30 and the second monitor switch of the second oscillation circuit part 40 (42) is interlocked to open the circuit and constitute a short circuit (gi, lj). That is, when the safety switch 46 does not stably open the circuit in the state where the microwave oven is open, it configures the short circuit to cut off the power supply of the low voltage transformer (L.V.T) supplying power to the microcomputer. Therefore, the microcomputer cannot operate the first and second power relays 33 and 43, thereby preventing the first and second magnetrons 34 and 44 from being oscillated while the microwave oven is open. Will be.

In addition, when a power relay is shorted in a conventional microwave oven in a state where the microwave oven is closed, the magnetron is continuously started indefinitely. However, the present invention is provided with a plurality of switching means for driving the magnetron, it is possible to cut off the power stably even if the power relay for controlling the output of the magnetron is short. That is, the safety relay 46 connected to the front end of the first oscillation circuit section 30 and the second oscillation circuit section 40 is interlocked with the first and second power relays 33 and 43, so that the When the first power relay 33 and the second power relay 43 are operated to oscillate the first magnetron 34 and the second magnetron 44, the safety relay 46 is also operated to simultaneously operate the circuit. Will be closed. Further, when the microcomputer turns off the first power relay 33 and the second power relay 43, the safety relay 46 is also turned off at the same time to open the circuit. Accordingly, even if the first power relay 33 or the second power relay 43 is shorted due to a defect, the safety relay 46 provided at the front end of the first power relay 33 and the second power relay 43 is turned off. By operating to open the circuit, it is possible to satisfactorily block the power supply to the first magnetron 34 and the second magnetron 44.

As described in detail above, according to the present invention, it is possible to prevent the magnetron from oscillating continuously when the power relay for controlling the output of the microwave (short circuit) is malfunctioned in the microwave oven having a plurality of magnetrons. Therefore, the operation reliability of the microwave oven can be improved.

Claims (2)

The first oscillation circuit portion for oscillating the first magnetron and the second oscillation circuit portion for oscillating the second magnetron are connected in parallel to the power supply terminal, and the first and second oscillation circuit portions are connected to the first and second magnetrons. First and second high voltage parts for supplying oscillation power, first and second power relays for controlling the output of the first and second magnetrons by intermittently intercepting power to the first and second high voltage parts, and In the microwave oven comprising a microcomputer for controlling the output of the first magnetron and the second magnetron by controlling the first and second power relay on / off, A safety relay connected to the front end of the first and second power relays and outputting a control signal in order to control the first and second power relays on and off in the micom, is provided in connection with the on and off control. The microwave oven characterized by the above. The method of claim 1, The safety relay is a microwave oven, characterized in that the connection between the power supply terminal and the parallel connection end of the first oscillation circuit portion and the second oscillation circuit portion.