CN201788431U - A Control Circuit of Electric Water Heater with Changeable Rated Power - Google Patents

Abstract

The utility model provides a control circuit of an electric water heater with changeable rated power, which comprises a heating circuit, a main control circuit and a first input circuit. The control circuit is characterized by further comprising a second input circuit which is used for limiting the maximum power value after a heating resistor is assembled, and the main control circuit further comprises a second signal input end, wherein the second signal input end comprises a control switch which can generate a high level signal or a low level signal respectively, and the output end of the second input circuit is connected with the second signal input end of the main control circuit. Compared with the prior art, the control circuit is additionally provided with the second input circuit of the control switch which can transmit two different signals of the high level signal and the low level signal, the second input circuit and the first input circuit jointly act on the main control circuit to control a relay to work, the control switch can be selected by a user to transmit the high level signal or the low level signal as required, and the main control circuit sets the rated power of the electric water heater according to the level signal transmitted by the second input circuit, so that the electric water heater can work with the proper rated power according to the practical installation environment when the electric water heater is installed.

Description

A control circuit for electric water heater with variable rated power

technical field

The utility model relates to an electric water heater control circuit, in particular to an electric water heater control circuit whose rated power can be changed. the

Background technique

Traditional water storage electric water heaters are usually marked with rated power and rated current on the nameplate of the product. In order to meet the different needs of users, the electric water heater is also equipped with multiple power options. Users can choose the appropriate working mode according to actual needs. . the

Although the existing electric water heaters have multiple power options, there is often only one rated power of the electric water heater, which is generally determined and cannot be changed when the product leaves the factory. When purchasing an electric water heater, ordinary household users can only choose the rated power and A product suitable for the current household electricity environment is installed. For example, the installation environment configuration is higher at the beginning, and the user chooses an electric water heater with a higher rated power for installation. In this case, the configuration environment of the user’s installation and wiring may not meet the installation conditions of high-power electrical appliances, resulting in the electric water heater with a large rated power cannot be used normally in the installation environment with low configuration. Only It is only applicable to replace the electric water heater with a smaller rated power. In this way, users have high requirements for the configuration of the installation environment during decoration, and they must also anticipate the development trend of other electrical appliances purchased in the future. The home appliance just may not be used normally, which brings great inconvenience to the user. the

Contents of the invention

The technical problem to be solved by the utility model is to provide an electric water heater control circuit capable of changing the rated power according to the actual installation environment in view of the above-mentioned prior art status. the

The technical scheme adopted by the utility model to solve the above-mentioned technical problems is: the electric water heater control circuit whose rated power can be changed includes

The heating circuit is composed of a plurality of heating resistors arranged in parallel and a relay connected in series in each of the heating resistor loops;

The main control circuit controls the opening and closing of each of the relays, the main control circuit includes a first signal input terminal and an output terminal, and the coil of each of the relays is connected to the output terminal of the main control circuit;

The first input circuit is used to set the combination mode of the heating resistors, the input signal of the first input circuit is obtained from the button on the operation panel of the electric water heater, the output terminal of the first input circuit and the main control The first signal input end of the circuit is connected;

It is characterized in that: the control circuit also includes a second input circuit for limiting the maximum power value after the combination of the heating resistors, and the main control circuit also includes a second signal input terminal, wherein the second input The circuit has control switches capable of generating high-level or low-level signals respectively, and the output terminal of the second input circuit is connected with the second signal input terminal of the main control circuit. the

In order to be able to change the rated power of the electric water heater, preferably, the second input circuit includes a resistor, a capacitor, and a dial switch as the control switch, wherein the dial switch includes the first gear and The two-speed dial switch of the second gear, one end of the dial switch is grounded, the other end of the dial switch is divided into three routes, one route is connected to the second input terminal of the main control circuit, and the second route passes through the The capacitor is grounded, and the third path is connected to the positive pole of the +5V power supply through the resistor. Therefore, the DIP switch can generate different level signals when it is toggled to the first gear and the second gear, and the main control circuit can set two different values of the rated power of the electric water heater according to the different level signals, so that The rated power of the electric water heater has two options, and the rated power of the electric water heater can be changed by flipping the code switch when necessary. the

In order to ensure the normal operation of the dial switch, as another preference, the second input circuit includes a fourth resistor, a fifth resistor and a dial switch as the control switch, wherein the dial switch is It includes a two-speed DIP switch with a first gear and a second gear, one end of the DIP switch is grounded, and the other end of the DIP switch is divided into two circuits through the fourth resistor, one of which is directly connected to the main The second input end of the control circuit is connected, and the second path is connected to the positive pole of the +5V power supply through the fifth resistor. A combination of resistors or resistors and capacitors is set at one end of the DIP switch, so that when the position of the DIP switch changes, the output level can change to achieve the purpose of changing the rated power. the

As a further preference, the second input circuit includes a resistor, a capacitor, and an electrical connector as the control switch, wherein the electrical connector is composed of a connector and a connector, the connector is grounded, and the One path of the plug-in is directly connected to the second input terminal of the main control circuit, the second path is grounded through the capacitor, and the third path is connected to the positive pole of the +5V power supply through the resistor. When the plug-in and connector of the electrical connector are combined into one, the circuit is turned on, and when the plug-in and connector of the electrical connector are separated, the circuit is disconnected, so different level signals can be generated according to the circuit on and off , so that the electrical connector has the same function as the dial switch. The main control circuit limits the current rated power value of the electric water heater according to different level signals. No matter how the user chooses the heating mode, the heating power of the electric water heater can only be at the rated power. within range. the

Preferably, the second input circuit includes a fourth resistor, a fifth resistor and an electrical connector as the control switch, wherein the electrical connector is composed of a connector and a connector, and the connector is grounded , the plug-in is divided into two paths through the fourth resistor, one path is directly connected to the second input terminal of the main control circuit, and the second path is connected to the +5V positive pole of the power supply through the fifth resistor. the

The heating circuit of the electric water heater can be realized by various circuits in the prior art. As a preference, the heating circuit includes a first resistor, a second resistor, a third resistor, a first relay, a second relay, and a third relay and the fourth relay, wherein the contacts of the first relay, the second relay and the third relay are moving contacts respectively, and the contacts of the fourth relay include a moving contact, a first static contact and the changeover contact of the second static contact, the coils of the first relay, the second relay, the third relay and the fourth relay are respectively connected to the output terminals of the main control circuit; One end is connected to the neutral line of the commercial power, the other end of the first relay contact is divided into three circuits, the first circuit is connected to the first static contact of the fourth relay through the first resistor, and the second circuit is connected to the first static contact of the fourth relay through the The second resistor is connected to one end of the third relay contact, the third path is connected to the second static contact of the fourth relay through the third resistor, and the moving contact of the fourth relay is connected to the second static contact of the fourth relay. One end of the contact of the second relay is connected, the other end of the contact of the second relay is connected to the live wire of the commercial power, and the other end of the contact of the third relay is connected to the live wire of the commercial power. the

The main control circuit can also be realized by using various circuits in the prior art. As a preference, the main control circuit includes a single-chip microcomputer with a model of S3F9488, and there is a serial connection between the single-chip microcomputer and the relay to drive the work of the relay. drive circuit. Since the output pin of the single-chip microcomputer cannot be directly connected to the relay coil, in order to ensure the normal operation of the relay, a driving circuit must be set between the relay and the single-chip microcomputer. Various circuit implementations in technology. the

Compared with the prior art, the utility model has the advantage that a second input circuit is added, and the second input circuit and the first input circuit work together on the main control circuit to further control the operation of the relay. The second input circuit has the ability to The control switch that sends two different signals of high level and low level can be selected according to the needs of the user to send the high level or low level signal, and the main control circuit determines the power level according to the two signals sent by the control switch of the second input circuit. There are two different rated power values of the water heater, so that the rated power of the electric water heater is more than one. When installing the electric water heater, the appropriate rated work can be selected according to the actual installation environment. When the installation environment changes, the operation of the control switch can be Changing the rated power of the electric water heater to ensure the normal operation of the electric water heater can make the same electric water heater not only meet the user needs of high configuration installation environment, but also meet the user needs of low configuration installation environment, making the installation of the product more flexible and applicable stronger. the

Description of drawings

Fig. 1 is a schematic diagram of the control circuit of Embodiment 1 of the present utility model. the

Fig. 2 is a schematic diagram of the control circuit of the second embodiment of the utility model. the

Fig. 3 is a schematic diagram of the control circuit of the third embodiment of the utility model. the

Fig. 4 is a schematic diagram of the control circuit of the fourth embodiment of the utility model. the

Fig. 5 is a schematic diagram of keys on the operation panel of the electric water heater according to the embodiment of the present invention. the

Detailed ways

The utility model is described in further detail below in conjunction with the accompanying drawings. the

Embodiment one, as shown in Figure 1:

The electric water heater control circuit of this embodiment includes a heating circuit 1, a main control circuit 2, a first input circuit 3 and a second input circuit 4, wherein the heating circuit 1 is composed of a plurality of heating resistors arranged in parallel and connected in series to each The relay in the heating resistance loop is formed; the main control circuit 2 is used to control the opening and closing of each relay. The first signal input terminal 211 and the second signal input terminal 212 of the control circuit 2, and the output terminal of the first input circuit 3 is connected with the first signal input terminal 211 of the main control circuit 2, and the output terminal of the second input circuit 4 It is connected to the second signal input terminal 212 of the main control circuit 2. Since the relay cannot be directly connected to the pins of the single-chip microcomputer 21 usually, a drive circuit 22 for driving the work of the relay needs to be set between the single-chip microcomputer 21 and each relay. The drive circuit 22 can adopt various circuit structures in the prior art, which is not the content to be protected by this patent, and will not be described in detail here. The input end of the drive circuit 22 is connected to the output pin of the single-chip microcomputer 21, and the output end of the drive circuit 22 The relay coil of the heating circuit 1 is then connected as the output end of the entire main control circuit 2 . the

Specifically, the heating circuit 1 of this embodiment includes a first resistor R1, a second resistor R2, a third resistor R3, a first relay J1, a second relay J2, a third relay J3 and a fourth relay J4, wherein the first The power of the first resistor R1 is 2500W, the power of the second resistor R2 is 2000W, and the power of the third resistor R3 is 2500W. The contacts of the first relay J1, the second relay J2 and the third relay J3 are respectively moving contacts, The contact of the fourth relay J4 is a changeover contact including a movable contact a, a first static contact b1 and a second static contact b2, the first relay J1, the second relay J2, the third relay J3 and the fourth relay J4 The coils of the relay J4 are respectively connected to the output terminals of the main control circuit 2;

One end of the contact of the first relay J1 is connected to the neutral line N of the mains, and the other end of the contact of the first relay J1 is divided into three routes, the first route passes through the first static contact of the first resistor R1 and the fourth relay J4 b1 is connected, the second path is connected with one end of the third relay J3 contact through the second resistor R2, the third path is connected with the second static contact b2 of the fourth relay J4 through the third resistor R3, and the moving point of the fourth relay J4 The contact a is connected to one end of the contact of the second relay J2, the other end of the contact of the second relay J2 is connected to the mains live line L, and the other end of the contact of the third relay J3 is connected to the mains live line L. the

The input signal of the first input circuit 3 mainly comes from the buttons on the operation panel of the electric water heater. Through the buttons on the operation panel, the user can select different heating modes, such as normal heating, extreme speed heating or capacity expansion heating, etc. These different heating modes The mode is realized by different combinations of heating resistors in the electric hot water;

The second input circuit is the inventive point of this embodiment. A control switch capable of generating high-level or low-level signals is provided in the second input circuit 4, and the second input circuit 4 is used to limit the combined heating resistance. The maximum power value, specifically, the second input circuit 4 preferably has the following circuit structure: the second input circuit 4 includes a 10KΩ resistor R, a 10000pF capacitor C and a dial switch T as a control switch, wherein the dial The code switch T is a two-speed dial switch including the first gear A and the second gear B. One end of the dial switch T is grounded, and the other end of the dial switch T is divided into three circuits. The first road and the main control The second input terminal of circuit 2 (that is, one of the input terminals of the single-chip microcomputer) is connected, the second circuit is connected to the ground through the capacitor C, and the third circuit is connected to the positive pole of the +5V power supply through the resistor R. Here, the purpose of the capacitor C and the resistor R is to realize the shifting of the dial switch T, to ensure that when the dial switch T is dialed to the first gear A, a low-level signal can be sent to the single-chip microcomputer 21, and the dial switch T When dialing to the second gear B, a high-level signal can be sent to the single-chip microcomputer 21. the

When the dial switch T is turned to the first gear A, the single-chip microcomputer 21 receives a low-level signal. At this time, the rated power of the electric water heater is limited to 2500W, that is, no matter how the heating resistors in the electric water heater are combined, the maximum power cannot More than 2500W; when the dial switch T is turned to the second gear B, the single-chip microcomputer 21 receives a high-level signal, and the rated power of the electric water heater is limited to 4500W, that is, after the heating resistance of the electric water heater is combined, the maximum power cannot exceed 4500W . the

Embodiment two, as shown in Figure 2:

The circuit structures of the heating circuit 1, the main control circuit 2 and the first input circuit 3 in the second embodiment and the first embodiment are all the same. The difference between this embodiment and the first embodiment is that the dial switch T in the second input circuit 4 The connection circuit with the single chip microcomputer 21 has been changed, and the combination of the original resistance and the capacitance has been replaced with two resistances. the

Specifically, the second input circuit 4 of this embodiment includes a fourth resistor R4 of 1KΩ, a fifth resistor R5 of 10KΩ, and a dial switch T as a control switch, wherein the dial switch T still includes the first gear One end of the dial switch T is grounded, and the other end of the dial switch T is divided into two circuits through the fourth resistor R4. The first circuit is directly connected to the main control circuit 2 The second input terminal is connected to the second input terminal, and the second circuit is connected to the positive pole of the +5V power supply through the fifth resistor R5. the

Embodiment three, as shown in Figure 3:

In this embodiment, the dial switch T is replaced by an electrical connector T', the electrical connector T' is composed of a connector T1' and a connector T2', the connector T2' is grounded, and the connector T1' is directly connected to the main control circuit 2. The second input is connected, the second is grounded through a 10000pF capacitor C, and the third is connected to the +5V positive pole of the power supply through a 10KΩ resistor R. the

When the plug-in T1' and the connector T2' are plugged together, at this time, it is equivalent to dialing the code switch T to the first gear A, the single-chip microcomputer 21 receives a low-level signal, and the rated power of the electric water heater is limited to 2500W ; When the plug-in T1' and the connector T2' were disconnected, at this moment, it was equivalent to dialing the dial switch T to the second gear B, and the single-chip microcomputer 21 received a high-level signal, and the rated power of the electric water heater was limited to 4500W. the

Embodiment four, as shown in Figure 4:

In this embodiment, on the basis of the third embodiment, the 10KΩ resistor R and the 10000pF capacitor are replaced with the fourth resistor R4 of 1KΩ and the fifth resistor R5 of 10KΩ. The resistor R4 is divided into two paths, the first path is directly connected to the second input terminal of the main control circuit 2, and the second path is connected to the +5V positive pole of the power supply through the fifth resistor R5. the

The above-mentioned embodiment one to embodiment four are four different circuit structures of the second input circuit 4, but the basic working principle is the same, the dial switch T and the electrical connector T1' can realize two different rated powers of the electric water heater (2500W and 4500W), generally speaking, the choice of rated power can only be adjusted by professionals according to customer needs before the product leaves the factory. Once the rated power of the electric water heater is selected and installed, it will not be changed until the next reinstallation. Perform another selection of rated power. the

As shown in Figure 5, it is a schematic diagram of keys on the operation panel of the electric water heater in this implementation, wherein K1 is the power-on key, K2 is the selection key for three heating modes (extreme speed heating, capacity-increasing heating and normal heating), and K3 is the upward movement key. K4 is a downward movement key, and K5 is a confirmation key. The working principle of the electric water heater in this embodiment is described in detail below in conjunction with the operation panel:

1. Before installation, if the dial switch T is turned to the first gear A or the plug-in T1' of the electrical connector T' is connected to the connector T2', at this time, the single-chip microcomputer 21 receives a low-level signal , The rated power of the electric water heater is selected as 2500W. the

(1) Press the K1 key to turn on the power. After the power is turned on, the electric water heater will work according to the heating mode before the last shutdown, and one of the icons of the two heating modes of extreme heating and capacity-increasing heating will remain on;

(2) Press the K2 key, when the rated power is 2500W, only one of the icons of the two heating modes of extreme speed heating and capacity expansion heating will flash;

(3) Press the K3 or K4 key to select the two heating modes of extreme speed heating and capacity expansion heating;

(4) Press the K5 key to confirm. After confirmation, one of the heating mode icons of extreme speed heating and capacity expansion heating will stop flashing and keep on. If you do not confirm, it will automatically return to the original heating mode after 5 seconds. the

When the electric water heater works at a rated power of 2500W, in the heating mode of extremely fast heating, only the first resistor R1 is heated, and the working power is 2500W; in the heating mode of increasing capacity heating, only the third resistor R3 is heated, and the working power is 2500W. Therefore, when the dial switch T is turned to the first gear A or the plug-in T1' and connector T2' of the electrical connector T' are connected, no matter which heating mode it is working in, the maximum power of the electric water heater All can only be limited within 2500W. the

2. Before installation, if the dial switch T is turned to the second gear B or the plug-in T1' and connector T2' of the electrical connector T' are disconnected, at this time, the single-chip microcomputer 21 receives a high-level signal , The rated power of the electric water heater is selected as 4500W. the

(1) Press the K1 key to turn on the power. After the power is turned on, the electric water heater will work according to the heating mode before the last shutdown, and one of the three heating mode icons of extreme speed heating, capacity-increasing heating and normal heating will remain on;

(2) Press the K2 key, when the rated power is 4500W, one of the icons of the three heating modes of extreme heating, capacity expansion heating and normal heating will flash;

(3) Press the K3 or K4 key to select three heating modes: extreme speed heating, capacity expansion heating and normal heating;

(4) Press the K5 key to confirm. After confirmation, one of the icons of the three heating modes of extreme speed heating, capacity expansion heating and normal heating will stop flashing and keep on. If not confirmed, it will automatically return to the original state after 5 seconds heating mode. the

When the electric water heater works at a rated power of 4500W, select the heating mode of extremely fast heating, the first resistor R1 and the second resistor R2 can be heated at the same time, and the working power is 4500W; The second resistor R2 and the third resistor R3 are heated at the same time, and the working power is 4500W; under the heating mode of normal heating, the third resistor R3 can be heated independently, and the working power is 2500W, so, turn the dial switch T to the second gear Bit B or when the plug-in T1' and connector T2' of the electrical connector T' are disconnected, no matter which heating mode it is working in, the maximum power of the electric water heater can only be limited within 4500W. the

Claims (7)

1. the changeable electric heater control circuit of rated power includes

Heater circuit is made up of a plurality of heating resistors that are arranged in parallel and the relay that is serially connected in each described heating resistor loop;

Governor circuit is controlled the switching of each described relay, and this governor circuit includes first signal input part and output terminal, and the coil of each described relay links to each other with the output terminal of described governor circuit;

First input circuit is used to set the array mode of described heating resistor, and the input signal of this first input circuit is taken from the button on the described operation of electric water heater panel, and first signal input part of the output terminal of this first input circuit and described governor circuit links to each other;

It is characterized in that: described control circuit also includes second input circuit that is used to limit the maximum power value after described heating resistor makes up, described governor circuit also includes the secondary signal input end, wherein, described second input circuit has the gauge tap that can produce high level or low level signal respectively, and the secondary signal input end of the output terminal of described second input circuit and described governor circuit links to each other.

2. the changeable electric heater control circuit of rated power according to claim 1, it is characterized in that: described second input circuit includes resistance, electric capacity and as the toggle switch of described gauge tap, wherein, described toggle switch is the two retaining toggle switchs that include first gear and second gear, one end ground connection of this toggle switch, the other end of this toggle switch divides three the tunnel, one the tunnel links to each other with second input end of described governor circuit, the second the tunnel through described capacity earth, and Third Road connects+the 5V positive source through described resistance.

3. the changeable electric heater control circuit of rated power according to claim 1, it is characterized in that: described second input circuit includes the 4th resistance, the 5th resistance and as the toggle switch of described gauge tap, wherein, described toggle switch is the two retaining toggle switchs that include first gear and second gear, one end ground connection of this toggle switch, the other end of this toggle switch divides two-way through described the 4th resistance, one the tunnel directly links to each other with second input end of described governor circuit, and the second the tunnel through described the 5th resistance connection+5V positive source.

4. the changeable electric heater control circuit of rated power according to claim 1, it is characterized in that: described second input circuit includes resistance, electric capacity and as the electric connector of described gauge tap, wherein, described electric connector is made up of plug-in unit and fitting, described fitting ground connection, described plug-in unit one tunnel is direct to link to each other with second input end of described governor circuit, and the second the tunnel through described capacity earth, and Third Road connects+the 5V positive source through described resistance.

5. the changeable electric heater control circuit of rated power according to claim 1, it is characterized in that: described second input circuit includes the 4th resistance, the 5th resistance and as the electric connector of described gauge tap, wherein, described electric connector is made up of plug-in unit and fitting, described fitting ground connection, described plug-in unit divides two-way through described the 4th resistance, and one the tunnel directly links to each other with second input end of described governor circuit, and the second the tunnel through described the 5th resistance connection+5V positive source.

6. according to the changeable electric heater control circuit of the described rated power of arbitrary claim in the claim 1～5, it is characterized in that: described heater circuit includes first resistance, second resistance, the 3rd resistance, first relay, second relay, the 3rd relay and the 4th relay, wherein, described first relay, the contact of second relay and the 3rd relay is respectively moving together contact, the contact of described the 4th relay is for including moving contact, the transfer contact of first stationary contact and second stationary contact, described first relay, second relay, the coil of the 3rd relay and the 4th relay links to each other with the output terminal of described governor circuit respectively;

One end of described first relay contact links to each other with the civil power zero line, the other end of this first relay contact is divided into three the tunnel, the first via links to each other through first stationary contact of described first resistance and described the 4th relay, the second tunnel end through described second resistance and described the 3rd relay contact links to each other, Third Road links to each other through second stationary contact of described the 3rd resistance and described the 4th relay, contact one end of the moving contact of described the 4th relay and described second relay links to each other, the other end of this second relay contact links to each other with the civil power live wire, and the other end of described the 3rd relay contact connects described civil power live wire.

7. the changeable electric heater control circuit of rated power according to claim 1, it is characterized in that: described governor circuit includes the single-chip microcomputer that model is S3F9488, is serially connected with the driving circuit that drives described relay work between described single-chip microcomputer and the described relay.

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