KR100268274B1 - Inrush relay circuit of a microwave oven for a high output - Google Patents

Abstract

An inrush relay circuit of a high power microwave oven is disclosed. The present invention provides a plurality of commercial exchange lines, one end of which is connected in parallel with each other from an input side, each of which has a high voltage transformer connected to its other end via a door switch, a monitor switch, and a load circuit. A plurality of power relay contacts each connected to a line to apply or cut off a commercial AC power to each of the door switch, the monitor switch, the load circuit and the high voltage transformer, and each inrush relay connected in parallel to the plurality of power relay contacts. An inrush relay circuit for a high power microwave oven having a contact and a plurality of inrush relay coils for turning on / off the plurality of inrush relay contacts, wherein a driving current is simultaneously conducted to the plurality of inrush relay coils. A microcomputer for applying an operation signal to the relay driver and the relay driver It includes. Accordingly, the plurality of power relay contacts can be individually turned on and off, and a plurality of inrush relay contacts can be simultaneously turned on and off by one relay driving unit, and can be operated without affecting each load. This simplifies configuration and operation and reduces manufacturing costs.

Description

Inrush relay circuit of high power microwave oven

The present invention relates to an inrush relay circuit of a high power microwave oven, and more particularly, to a high power microwave oven which simplifies the configuration and operation of a relay driver for turning on / off a plurality of inrush relay contacts. It relates to an inrush relay circuit.

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.

On the other hand, in recent years, a high power / large capacity microwave oven is required in convenience stores and various offices, etc. As a result, high power microwave ovens having a plurality of high voltage transformers and magnetrons are widely used.

1 and 2 show a control circuit diagram illustrating such an inrush relay circuit of a conventional high power microwave oven. Here, a general microwave oven is provided with various load circuits such as a low voltage transformer (LVT), a monitor fuse, a lamp, a fan motor, and a timer. Here, the above-described various load circuits will be omitted and only the main parts thereof are shown.

1, the first and second commercial AC lines L1 and L2 input normal commercial AC power supplies 110V or 220V through one end thereof, and the other end thereof is the first high voltage transformer HVT1. It is connected to both ends of the primary coil. Here, a fuse FUSE1, a door switch SW1 and a monitor switch SW3 are connected in series to the first commercial AC line L1, and a power relay contact RY30 to the second commercial AC line L2. ) And inrush relay contact RY10 are connected in parallel.

The fuse FUSE1 cuts off an overcurrent of a load circuit (not shown), and the door switch SW1 and the monitor switch SW3 are turned on / off according to the opening / closing state of the door (not shown). The safety function will be performed.

The power relay contact RY30 is turned on and off by the microcomputer 1 and a driving unit (not shown), and the AC power supply circuit (not shown) and each of the high-voltage transformers (HVT1) and HVT2 are used. ) Is applied. The inrush relay contact RY10 is operated for several seconds immediately before the power relay contact RY30 is turned on to remove the inrush current.

Further, third and fourth commercial alternating lines L3 and L4 connected in parallel to the input sides of the first and second commercial alternating lines L1 and L2 are provided, and the third and fourth commercial alternating lines ( L3) and L4 are respectively connected to both ends of the primary coil of the second high voltage transformer HVT2.

In addition, a fuse FUSE2, a door switch SW2, and a monitor switch SW4 are connected in series to the third phase ac line L3, and a power relay contact RY40 is connected to the fourth phase ac line L4. ) And inrush relay contacts RY20 are connected in parallel, and the respective operations are the same as those of the above-described fuse FUSE1, door switch SW1, monitor switch SW3, and respective relay contacts RY30 and RY10. .

On the secondary coil side of each of the high voltage transformers HVT1 and HVT2, high voltage capacitors HVC1, HVC2, HVD1, HVD2, and magnetron MTG1, MGT2 for generating microwaves are provided, respectively. do.

According to Fig. 2, the microcomputer 1 outputs an operation signal of a normal square wave, and the relay driver 2 and 3 are switched in accordance with the operation signal of the microcomputer 1 so that the inrush relay coils RY11 and RY21 are operated. To conduct or cut off the current. Accordingly, when current is conducted to the inrush relay coils RY11 and RY21, the inrush relay contacts RY10 and RY20 of FIG. 1 are turned on, and the inrush relay contacts RY10 and RY20 when the current is cut off. ) Is off.

To this end, the relay driver 2 or 3 includes switching transistors TR1 and TR2, and a plurality of resistors R3, R4 and R5 for applying a base voltage to the transistors TR1 and TR2. It consists of (R6). Further, reference numerals D1 and D2 connected in parallel with each of the inrush relay coils RY11 and RY21 are diodes for preventing reverse voltage. Reference numerals R1 and R2 in FIG. 1 are current limiting resistors.

The operation of the inrush relay circuit of the conventional high-power microwave oven configured as described above, first, the microcomputer 1 simultaneously turns on / off the power relay contacts RY30 and RY40 or turns them on and off separately. Drive the microwave. Although not illustrated in the drawing, the microcomputer 1 operates the power relay contacts RY30 and RY40 through respective relay driving units and power relay coils. On the other hand, when the microcomputer 1 is turned on the power relay contact (RY30) (RY40), prior to this, the inrush relay contact (RY10) (RY20) connected in parallel to the power relay contact (RY30) (RY40), respectively, several seconds ( By turning on during i), the inrush current at the initial power-on is removed.

Referring to the driving state of the inrush relay contacts RY10 and RY20, the microcomputer 1 outputs an operation signal, and the operation signal is the resistors R3 and R4 of the relay driver 2 and 3 (R5). Is converted to a predetermined voltage via R6 and applied to the base terminal of the transistors TR1 and TR2. Accordingly, the transistors TR1 and TR2 are turned on so that each power supply voltage + 24V conducts each of the inrush relay coils RY11 and RY21.

Accordingly, the inrush relay contacts RY10 and RY20 of FIG. 1 are turned on for a few seconds, so that the first and second commercial alternating lines L1 and L2 or the third and fourth commercial alternating lines L3 are turned on. The inrush current flowing in L4 is bypassed, and then the power relay contacts RY30 and RY40 are operated.

In addition, as the power relay contacts RY30 and RY40 are turned on, each load circuit (not shown) is operated, and at the same time, a commercial AC power supply is provided on the primary coil side of each of the high voltage transformers HVT1 and HVT2. Is applied. Accordingly, each of the high voltage transformers HVT1 and HVT2 outputs a high voltage through the secondary coil to drive the plurality of magnetrons MGT1 and MGT2, and the microwaves emitted from the magnetrons MTG1 and MGT2. Food is heated / cooked.

However, the inrush relay circuit of the conventional high power microwave oven operated as described above is configured to drive the microwave by turning on / off the plurality of power relay contacts simultaneously or separately on / off. Accordingly, a plurality of relay driving units corresponding to the inrush relay contacts corresponding to the power relay contacts must be provided so as to be individually turned on and off, thereby increasing the required parts and complicating the configuration and operation. There is a problem that the manufacturing cost rises.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, high output power to reduce the manufacturing cost by simplifying the configuration and operation of the relay driver for turning on / off a plurality of inrush relay contacts An inrush relay circuit for a microwave oven is provided.

1 and 2 is a control circuit diagram showing an inrush relay circuit of a conventional high-power microwave oven,

3 is a control circuit diagram showing a preferred embodiment of the inrush relay circuit of the high power microwave oven according to the present invention.

Explanation of symbols on the main parts of the drawings

10: microcomputer 20: relay drive unit

TR10: Transistor RY11, RY21: Inrush Relay Coil

RY10, RY20: Inrush relay contacts RY30, RY40: Power relay contacts

L1 to L4: Commercial exchange line SW1, SW2: Door switch

SW3, SW4: Monitor switch HVT1, HVT2: High voltage transformer

MGT1, MGT2: Magnetron

A feature of the inrush relay circuit of the high power microwave oven according to the present invention for achieving this object is that one end thereof is connected in parallel from the input side, and the other end thereof is connected to each other via a door switch, a monitor switch and a load circuit. A plurality of commercial AC lines connected to each of the high voltage transformers, and a plurality of powers connected to the plurality of commercial AC lines to supply or cut off the AC power to the respective door switches, monitor switches, load circuits, and high voltage transformers. A high power microwave oven having a relay contact, each inrush relay contact connected in parallel to the plurality of power relay contacts, and a plurality of inrush relay coils for turning on / off the plurality of inrush relay contacts. In the rush relay circuit, a driving current is simultaneously applied to the plurality of inrush relay coils. It includes a relay driver for conducting and a microcomputer for applying an operation signal to the relay driver.

Accordingly, the plurality of power relay contacts can be individually turned on and off, and a plurality of inrush relay contacts can be simultaneously turned on and off by one relay driving unit, and can be operated without affecting each load. This simplifies configuration and operation and reduces manufacturing costs.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the inrush relay circuit of the high power 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 control circuit diagram showing a preferred embodiment of the inrush relay circuit of the high power microwave oven according to the present invention.

First, as shown in FIG. 1, one end thereof is connected in parallel from the input side, respectively, and through the other door switch SW1 (SW2), monitor switch SW3 (SW4), and a load circuit (not shown). A plurality of commercial exchange lines L1, L2, L3, L4 connected to respective high voltage transformers HVT1, HVT2, and the plurality of commercial exchange lines L1, L2, L3. L4) is connected to each of the door switch SW1 (SW2), the monitor switch (SW3) (SW4), the load circuit (not shown) and the high-voltage transformer (HVT1) (HVT2) to supply or cut off the commercial AC power A plurality of power relay contacts RY30 and RY40, and respective inrush relay contacts RY10 and RY20 connected in parallel to the plurality of power relay contacts RY30 and RY40, and the plurality of inrushes. A plurality of inrush relay coils RY11 and RY21 for turning on / off the relay contacts RY10 and RY20 are provided as in the prior art.

However, the main features of the present invention, as shown in Figure 3, the only one relay drive unit 20 for driving current is simultaneously conducted to the plurality of inrush relay coil (RY11) (RY21), and the relay The microcomputer 10 applies an operation signal to the driver 20.

The relay driver 20 includes a switching transistor TR10 and a plurality of resistors R1 and R2 for applying a base voltage to the transistor TR10. Further, reference numerals D1 and D2 connected in parallel with the inrush relay coils RY11 and RY21 are diodes for preventing the reverse voltage.

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

The microcomputer 10 simultaneously turns on / off the power relay contacts RY30 and RY40, or separately turns them on and off to drive the microwave oven. On the other hand, when the microcomputer 10 turns on the power relay contacts RY30 and RY40, the inrush relay contacts RY10 and RY20 connected to the power relay contacts RY30 and RY40 in parallel, respectively. By turning on for a few seconds, the inrush current at the initial power-on is removed.

To this end, the present invention is configured to drive a microwave by turning on / off a plurality of power relay contacts RY30 and RY40 at the same time as described above or separately, respectively, and the inrush relay. The contacts RY10 and RY20 are configured to simultaneously turn on / off as one relay driver 20.

That is, when the plurality of power relay contacts RY30 and RY40 are turned on at the same time, the driving state of the inrush relay contacts RY10 and RY20 will be described. The signal is converted into a predetermined voltage through the resistors R10 and R20 of the relay driver 20 and applied to the base terminal of the transistor TR10. Thus, the transistor TR10 is turned on so that the power supply voltage (+ 24V) is simultaneously conducted to each of the inrush relay coils RY11 and RY21.

Accordingly, the inrush relay contacts RY10 and RY20 of FIG. 1 are turned on together for a few seconds, so that the first and second commercial exchange lines L1 and L2 or the third and fourth commercial exchange lines L3 are provided. Inrush current flowing through L4 is bypassed, and then the power relay contacts RY30 and RY40 are operated.

In addition, as the power relay contacts RY30 and RY40 are turned on, each load circuit (not shown) is operated, and at the same time, a commercial AC power supply is provided on the primary coil side of each of the high voltage transformers HVT1 and HVT2. Is applied. Accordingly, each of the high voltage transformers HVT1 and HVT2 outputs a high voltage through the secondary coil to drive the plurality of magnetrons MGT1 and MGT2, and the microwaves emitted from the magnetrons MTG1 and MGT2. Food is heated / cooked.

On the other hand, when only one power relay contact (for example, RY30) is turned on, the driving state of the inrush relay contacts RY10 and RY20 is two inrush relay contacts RY10 and RY20 as described above. ) Operates simultaneously for several seconds.

Therefore, other than the high voltage transformer HVT1 to be operated, the current is also instantaneously applied to the high voltage transformer HVT2. However, while the magnetron MTG2 is driven by the high voltage transformer HVT2 for at least 1 second to 2 seconds, the operating time of the inrush relay contact RY10 and RY20 is within several seconds. It does not affect the operation of the high voltage transformer (HVT2) and the magnetron (MGT2).

Therefore, the plurality of power relay contacts RY30 and RY40 are individually turned on and off, and a plurality of inrush relay contacts RY10 and RY20 are simultaneously turned on and off with one relay driver 20. The operation of each high voltage transformer (HVT1) (HVT2) and other loads can be operated without mutual influence, thereby simplifying the construction and operation and reducing the manufacturing cost.

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 inrush relay circuit of the high power microwave oven according to the present invention, a plurality of inrush relay contacts are simultaneously turned on and off with a plurality of power relay contacts. Although it can be turned on and off without affecting each load, there is an effect of simplifying the configuration and operation and reducing the manufacturing cost.

Claims (1)

One end thereof is connected in parallel to each other from the input side, and is connected to a plurality of commercial exchange lines each having a high voltage transformer connected to the other end thereof through a door switch, a monitor switch, and a load circuit, respectively. A plurality of power relay contacts for applying or disconnecting a commercial AC power to each of the door switch, the monitor switch, the load circuit and the high voltage transformer, each inrush relay contact connected in parallel to the plurality of power relay contacts, and In the inrush relay circuit of a high power microwave oven having a plurality of inrush relay coils for turning on / off the plurality of inrush relay contacts, a relay driver for simultaneously driving current to the plurality of inrush relay coils ; And a microcomputer for applying an operation signal to the relay driving unit.