First, the shape and structure of the rice cooker
The figure shows the shape and structure of a typical rice cooker, which can be divided into mechanically controlled rice cookers and microcomputer-controlled rice cookers according to the control mode. From the picture, the shape of these two rice cookers is roughly the same, and both consist of a lid, a pot body and an operation display panel.
1. The shape and structure of the mechanically controlled rice cooker
There are two shapes of mechanically controlled rice cookers, one is that the lid is connected to the pot body, and the other is that the lid is separated from the pot body, as shown in the figure.
2. The shape and structure of the microcomputer-controlled rice cooker
The shape of the microcomputer-controlled rice cooker is roughly the same as that of the mechanically controlled rice cooker, and there are two shapes: the lid is connected to the pot body and the lid is separated from the pot body, but the lid of the microcomputerized rice cooker can be locked, as shown in the figure.
3. Operate the display panel
The rice cooker operation display panel is the main device for operating the rice cooker working and working light indication. The operation display panel of the mechanically controlled rice cooker is relatively simple, and the power supply is connected to the power supply by mechanical means for heating, and two lamps are used as cooking instructions and heat preservation instructions. The operation display panel of the microcomputer-controlled rice cooker is more complicated, because it is controlled by the microcomputer, so the number of light-touch buttons is relatively large, and the function is more powerful. The operation display panel of the rice cooker is shown in the figure.
For more information inquiry, search the official number: maintenance data number.
Second, the internal structure of the rice cooker
The internal structure of a mechanically controlled rice cooker is mainly composed of electric heating plate, magnetic steel temperature limiter, automatic warmer, mechanical control mechanism and power cord and other components. The internal structure of the microcomputer-controlled rice cooker is basically similar to the mechanically controlled type, and there are also electric hot plates and magnetic steel temperature limiters, and the difference from the mechanically controlled rice cooker is that the microcomputer is used to control the entire working process of the rice cooker, and the circuit structure is more complicated.
1. Internal structure of mechanically controlled rice cooker
The figure below shows the internal structure diagram of the mechanically controlled rice cooker, which is composed of an electric heating plate, a magnetic steel temperature limiting device, a heat preservation device, a power supply circuit and a working light indication circuit.
1) Electric heating plate
The electric hot plate is the heart of the rice cooker circuit. The electric heating plate is made by placing the electric heating tube in a mold and then casting it with aluminum alloy, and it has sufficient strength and good thermal conductivity. There is a circular hole in the middle of the hot plate for installing the magnetic steel thermolimiter. The structure of the electric hot plate is shown in the figure.
2) Magnetic steel temperature limiting device
The magnetic steel temperature limiting device is the key component of the rice cooker, which is mainly composed of magnets, contact switches and levers. It automatically turns off the power after the rice is cooked, preventing the rice from burning. The magnetic steel temperature limiting device is shown in the figure.
3) Thermal insulation device
There are generally two kinds of insulation devices for mechanically controlled rice cookers, one is a bimetal plate warmer and the other is a resistance insulation sheet, as shown in the figure. The function of the insulation device is to ensure that the temperature of the inner pot of the rice cooker is at a certain temperature value after the rice is cooked (the magnetic steel thermolimiter is powered off). In recent years, the most used in the production of rice cookers is the electronic insulation sheet type warmer, which has the characteristics of simple structure, convenient installation, cheap price and no adjustment; Bimetal plate heaters are more complex, expensive, and need to adjust the screw position to calibrate the holding temperature.
4) Power supply circuit
The power circuit is mainly composed of power cord plugs, sockets and overtemperature fuses, etc., and most rice cookers now use power cords with triangular plugs and sockets, one inside is a live wire, another is a zero wire, and one is a yellow and green protective grounding wire. Since most rice cookers are metal shells, for the safety of users, the protective grounding wire must be connected to the metal shell to prevent electric shock accidents. The overtemperature fuse is connected in series in the AC 220V power supply circuit, and its function is that when the magnetic steel thermolimiter can not operate or the bimetal plate thermostat contacts are connected, the heating temperature of the rice cooker keeps rising, and when the temperature reaches 145 hooks, the overtemperature fuse is burned off, cutting off the power supply to protect the heating plate and other electrical appliances. The structure of the rice cooker power supply circuit is shown in the figure.
5) Working light indicator circuit
The rice cooker work indicator circuit mainly has cooking indicator and heat preservation indicator. Most rice cooker indicators are indicated by a glass bubble (a current-limiting resistor in series). The cooking indicator and the electric heating plate are connected in parallel, and the insulation indicator and the insulation device are connected in parallel. The work indicator circuit is shown in the figure.
2. The internal structure of the microcomputer-controlled rice cooker
The internal structure diagram of the microcomputer-controlled rice cooker, which is composed of electric heating plate, thermistor temperature limiting device, power circuit and main control circuit board, thermal insulation device and operation display circuit board.
Like the mechanically controlled rice cooker hot plate, as shown in the figure, the electric hot plate of the microcomputer-controlled rice cooker is also a resistive heating device, but the current passed into the electric hot plate is controlled by the main control relay, and the drive of the relay is controlled by the microcomputer. The middle round hole of the heating plate is equipped with a thermistor temperature limiter.
2) Thermistor temperature limiting device
As shown in the figure, the thermistor thermolimiter is installed at the bottom of the rice cooker, which always senses the temperature at the bottom of the pot, and converts the temperature change into an electrical signal to transmit to the microcomputer control board, which then controls whether the heat plate continues to heat. It differs from the magnet temperature limiting principle of mechanically controlled rice cookers, and thermistor temperature limiters are PTC elements.
3) Power circuit and main control circuit board
The function of the power circuit and the main control circuit board is to provide AC 220V voltage for the rice cooker hot plate, and provide +13V and +5V DC voltage after the 220V AC voltage is stepped, rectified, filtered and stabilized by the transformer to power the drive control circuit and microcomputer. The power circuit and main control circuit board are shown in the figure.
4) Thermal insulation device
The heat preservation device of the microcomputer-controlled rice cooker adopts a bimetal plate thermostat, which automatically outputs a power-off signal and transmits it to the microcomputer after the rice cooker is cooked, and the microcomputer outputs a driving signal to control the relay to power off and cut off the current in the electric hot plate. The insulation device is shown in the figure.
5) Operation display board
The operation display circuit board is installed in front of the rice cooker, which is the core of the microcomputer control, and the control circuit of the rice cooker is all installed in the operation display circuit board. Its function is to receive manual operation instructions and control the heating of the electric hot plate, and at the same time display the time and working status by the digital tube, as shown in the figure.
For more information inquiry, search the official number: maintenance data number.
1) Electric heating plate