CN204012659U - Microwave oven and safety protective circuit thereof - Google Patents
Microwave oven and safety protective circuit thereof Download PDFInfo
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- CN204012659U CN204012659U CN201420423598.0U CN201420423598U CN204012659U CN 204012659 U CN204012659 U CN 204012659U CN 201420423598 U CN201420423598 U CN 201420423598U CN 204012659 U CN204012659 U CN 204012659U
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Abstract
The safety protective circuit that the utility model discloses a kind of microwave oven, it comprises: the current detector that detects the operating current of the heater of microwave oven; Control the first switch element that electric main is input to heater, the first switch element is connected between electric main and heater; Be connected to the safety protection switch unit between electric main and heater; Controller; controller is connected with current detector, the first switch element and safety protection switch unit; wherein; after controller control the first switch element disconnects; if current detector detects operating current and be greater than preset value, controller controls to cut off the electric main that is input to heater to safety protection switch unit.This safety protective circuit can be in the first switch element relay there is to cut off when merge contact the power supply of heater, prevent heater continuous heating and bring potential safety hazard.The invention also discloses a kind of microwave oven.
Description
Technical field
The utility model relates to heating device for cooking technical field, particularly a kind of safety protective circuit of microwave oven and a kind of microwave oven with this safety protective circuit.
Background technology
Microwave oven is in heating process, and the food temperature in furnace chamber is understood fast rise, thereby the temperature of microwave oven miscellaneous part also can be along with rising.Once and appearance is heated the situation that can not stop extremely, will cause microwave oven body temperature to continue to raise and cause potential safety hazard.
Existing electronic micro-wave oven, the switch that internal control heater is opened is generally relay.Internal circuit is controlled the open and close of heater by the break-make of control relay.But while sticking together, at this moment relay also cannot be disconnected by internal circuit control no longer again, thereby makes heater by continuous heating if relay occurs that contact is merged, so not only can burning foods, and there is certain potential safety hazard.
Utility model content
The purpose of this utility model is intended at least solve above-mentioned technological deficiency.
For this reason; first object of the present utility model is to propose a kind of safety protective circuit of microwave oven; can accurately detect whether the relay of controlling heater switch contact fusion occurs; and occur when merge contact to cut off the power supply of heater at relay, prevent heater continuous heating and bring potential safety hazard.
Second object of the utility model is to propose a kind of microwave oven.
For achieving the above object, a kind of safety protective circuit of microwave oven that the utility model first aspect proposes, comprising: for detection of the current detector of the operating current of the heater of described microwave oven; The first switch element that is input to described heater for controlling electric main, described the first switch element is connected between described electric main and described heater; Safety protection switch unit, described safety protection switch unit is connected between described electric main and described heater; Controller; described controller is connected with described current detector, described the first switch element and described safety protection switch unit; wherein; after described in described controller control, the first switch element disconnects; if described current detector detects described operating current and be greater than preset value, described controller controls to cut off to described safety protection switch unit the electric main that is input to described heater.
According to the safety protective circuit of microwave oven of the present utility model, detect by increase heater operating current current detector and be connected to electric main and heater between safety protection switch unit judge whether the first switch element exists extremely, if existing the first relay in abnormal for example the first switch element that contact occurs, the first switch element merges, controller cuts off by controlling safety protection switch unit the electric main that is input to heater, prevent heater continuous firing and potential safety hazard that superheated causes food to burn and brings, realize the safety protection function of microwave oven, ensure that microwave oven safety is used reliably, meet user's demand.
Wherein, when described current detector is current transformer, the primary side of described current transformer is connected on the zero line or live wire of described electric main, and described safety protective circuit also comprises the signaling conversion circuit being connected with the secondary side of described current transformer.
Particularly, described signaling conversion circuit comprises: the first resistance, and one end of described the first resistance is connected with one end of the secondary side winding of described current transformer; The first diode, the anode of described the first diode is connected with the other end of described secondary side winding, and the negative electrode of described the first diode is connected with the other end of described the first resistance; The first electric capacity, described the first electric capacity is in parallel with described the first resistance; The second electric capacity, ground connection after one end of described the second electric capacity is connected with one end of described the first electric capacity; The second resistance, one end of described the second resistance is connected with the other end of described the first electric capacity, after the other end of described the second resistance is connected with the other end of described the second electric capacity, is connected with described controller.
Particularly, described the first switch element comprises: the first relay, and the switch series in described the first relay is associated on the zero line or live wire of described electric main, one end ground connection of the coil in described the first relay; The first triode, the collector electrode of described the first triode is connected with the other end of the coil in described the first relay, and the base stage of described the first triode is connected with described controller, and the emitter of described the first triode is connected with the power supply of predeterminated voltage.
Particularly, described safety protection switch unit comprises: normally closed relay, and the switch series in described normally closed relay is associated on the zero line or live wire of described electric main, one end ground connection of the coil in described normally closed relay; The second triode, the collector electrode of described the second triode is connected with the other end of the coil in described normally closed relay, and the base stage of described the second triode is connected with described controller, and the emitter of described the second triode is connected with the power supply of described predeterminated voltage; Wherein, in the time that described operating current is greater than described preset value, the second triode conducting disconnects to control described normally closed relay described in described controller control, to cut off the electric main that is input to described heater.
In addition, described safety protection switch unit comprises: the second relay, and the switch in described the second relay is connected between the zero line and live wire of described electric main, one end ground connection of the coil in described the second relay; The 3rd triode, the collector electrode of described the 3rd triode is connected with the other end of the coil in described the second relay, and the base stage of described the 3rd triode is connected with described controller, and described the 3rd emitter of triode and the power supply of described predeterminated voltage are connected; Wherein, in the time that described operating current is greater than described preset value, described in described controller control, the 3rd triode conducting, to control described the second relay closes, so that described electric main short circuit is connected on the fuse on described live wire with fusing, is cut off the electric main that is input to described heater.
A kind of microwave oven that the utility model second aspect proposes, comprises the safety protective circuit of above-mentioned microwave oven.
According to microwave oven of the present utility model, in the time of end of cooking or time-out, control the first switch element and disconnect cutting off the electric main that is input to heater, if now detect that the operating current of heater is greater than preset value, illustrate that the first switch element does not disconnect, represent that the first switch element exists the first relay in abnormal for example the first switch element that contact fusion occurs, cut off by controlling safety protection switch unit the electric main that is input to heater, thereby prevent heater continuous firing and potential safety hazard that superheated causes food to burn and brings, realize safety protection function.Therefore, microwave oven of the present utility model can use safely and reliably, meets user's demand.
The aspect that the utility model is additional and advantage in the following description part provide, and part will become obviously from the following description, or recognize by practice of the present utility model.
Brief description of the drawings
The utility model above-mentioned and/or additional aspect and advantage will become from the following description of the accompanying drawings of embodiments obviously and easily and understand, wherein:
Fig. 1 is according to the block diagram of the safety protective circuit of the microwave oven of the utility model embodiment;
Fig. 2 is according to the circuit diagram of the safety protective circuit of the microwave oven of an embodiment of the utility model;
Fig. 3 is according to the circuit diagram of the safety protective circuit of the microwave oven of another embodiment of the utility model;
Fig. 4 is according to the flow chart of the safety protection control method of the microwave oven of the utility model embodiment; And
Fig. 5 is according to the flow chart of the safeguard protection subprogram of the single-chip microcomputer of an embodiment of the utility model.
Embodiment
Describe embodiment of the present utility model below in detail, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has the element of identical or similar functions from start to finish.Be exemplary below by the embodiment being described with reference to the drawings, only for explaining the utility model, and can not be interpreted as restriction of the present utility model.
Disclosing below provides many different embodiment or example to be used for realizing different structure of the present utility model.Of the present utility model open in order to simplify, hereinafter the parts to specific examples and setting are described.Certainly, they are only example, and object does not lie in restriction the utility model.In addition, the utility model can be in different examples repeat reference numerals and/or letter.This repetition is in order to simplify and object clearly, itself do not indicate the relation between discussed various embodiment and/or setting.In addition, the various specific technique that the utility model provides and the example of material, but those of ordinary skill in the art can recognize the property of can be applicable to of other techniques and/or the use of other materials.In addition, First Characteristic described below Second Characteristic it " on " structure can comprise that the first and second Characteristics creations are the direct embodiment of contact, also can comprise the embodiment of other Characteristics creation between the first and second features, such the first and second features may not be direct contacts.
In description of the present utility model, it should be noted that, unless otherwise prescribed and limit, term " installation ", " being connected ", " connection " should be interpreted broadly, for example, can be mechanical connection or electrical connection, also can be the connection of two element internals, can be to be directly connected, and also can indirectly be connected by intermediary, for the ordinary skill in the art, can understand as the case may be the concrete meaning of above-mentioned term.
Describe with reference to the accompanying drawings according to the safety protective circuit of the microwave oven of the utility model embodiment proposition, there is the microwave oven of this safety protective circuit and the safety protection control method of microwave oven.
Fig. 1 is according to the block diagram of the safety protective circuit of the microwave oven of the utility model embodiment.As shown in Figure 1, the safety protective circuit of this microwave oven comprises: current detector 10, the first switch element 20, safety protection switch unit 30 and controller 40.
Wherein, current detector 10 is for detection of the operating current of the heater 1 of described microwave oven, and as shown in Figure 1, current detector 10 is connected on the zero line N of electric main; The first switch element 20 is input to heater 1 and controls the switch of heater 1 for controlling electric main, the first switch element 20 is connected between described electric main and heater 1, for example, be connected on the zero line N of electric main; Safety protection switch unit 30 is connected between described electric main and heater 1, for example, be also connected on the zero line N of electric main; Controller 40 is connected with safety protection switch unit 30 with current detector 10, the first switch element 20; wherein; control after the first switch element 10 disconnections at controller 40; if current detector 10 detects described operating current and be greater than preset value, controller 40 controls to cut off the electric main that is input to heater 1 to safety protection switch unit 30.And, on the live wire L of electric main, be in series with fuse F1 and temperature detect switch (TDS) 2.
That is to say, after cooking in microwave oven finishes or suspends, this Time Controller controlled first switch element disconnect make heater disconnect be being connected of electric main with power supply, if now current detector can also detect that the operating current of heater is that operating current is greater than preset value, illustrate that the first switch element occurs that the first relay in abnormal for example the first switch element occurs that merge contact and not disconnection, controller control security protection unit so that heater disconnect and being connected of power supply, make the heater can continuous heating and bring potential safety hazard, also can not carry out burning foods because of over-heating.
According to an embodiment of the present utility model; when current detector 10 is current transformer T1; the primary side of current transformer T1 is connected on the zero line N or live wire L of described electric main; safety protective circuit also comprises the signaling conversion circuit 50 being connected with the secondary side of current transformer T1; as shown in Figure 2 or Figure 3, the primary side of current transformer T1 is connected on the zero line N of electric main.Current transformer T1 is for detection of the operating current of heater 1.
Particularly, as shown in Figure 2 or Figure 3, signaling conversion circuit 50 comprises: the first resistance R 1, the first diode D1, the first capacitor C 1, the second capacitor C 2 and the second resistance R 2.Wherein, one end of the first resistance R 1 is connected with one end of the secondary side winding of current transformer T1, the first anode of diode D1 and the other end of described secondary side winding are connected, the negative electrode of the first diode D1 is connected with the other end of the first resistance R 1, the first capacitor C 1 is in parallel with the first resistance R 1, ground connection after one end of the second capacitor C 2 is connected with one end of the first capacitor C 1, one end of the second resistance R 2 is connected with the other end of the first capacitor C 1, after the other end of the second resistance R 2 is connected with the other end of the second capacitor C 2, is connected with for example single-chip microcomputer of controller 40.
In embodiment of the present utility model, the signaling conversion circuit being formed by the first diode D1, the first resistance R 1, the first capacitor C 1, the second resistance R 2, the second capacitor C 2, for converting current signal to digital signal I_Detect, wherein digital signal high level represents that there is operating current in the loop of heater 1, and operating current is greater than preset value.For example, operating current when heater is normally worked is 5～7A, while work, electric current is less than 1A, when the secondary side of current transformer T1 is worked at heater, secondary side output current is 5～7mA, while work, output current is less than 1mA, the electric current of current transformer T1 secondary side output is through diode D1, resistance R 1, after capacitor C 1 rectifying and wave-filtering, output voltage signal, through resistance R 2, the low pass filter that capacitor C 2 forms, filtering noise is exported pure voltage signal, wherein, current versus voltage relation: 1mA/0.75V, while being heater work, export 3.75～5.25V, while work, output is less than 0.75V.
In embodiment of the present utility model, the first switch element 20 comprises: the first relay R LY1 and the first triode QR1.Switch series in the first relay R LY1 is associated on the zero line or live wire of described electric main, and as shown in Figure 2 or Figure 3, the switch series in the first relay R LY1 is associated on the zero line N of described electric main, one end ground connection of the coil in the first relay R LY1; The collector electrode of the first triode QR1 is connected with the other end of the coil in the first relay R LY1, and the base stage of the first triode QR1 is connected with controller 40, and the emitter of the first triode QR1 is connected with the power supply of for example 12V of predeterminated voltage.
According to an embodiment of the present utility model, safety protection switch unit 30 comprises: normally closed relay RLY2 and the second triode QR2.Switch series in normally closed relay RLY2 is associated on the zero line or live wire of described electric main, and as shown in Figure 2, the switch series in normally closed relay RLY2 is associated on the zero line of described electric main, one end ground connection of the coil in normally closed relay RLY2; The collector electrode of the second triode QR2 is connected with the other end of the coil in normally closed relay RLY2, and the base stage of the second triode QR2 is connected with controller 40, and the emitter of the second triode QR2 is connected with the power supply of for example 12V of predeterminated voltage.Wherein, in the time that described operating current is greater than described preset value, controller 40 is controlled the second triode QR2 conducting and is disconnected to control normally closed relay RLY2, to cut off the electric main that is input to heater 1.
That is to say, in the present embodiment, as shown in Figure 2, after cooking in microwave oven finishes, for example single-chip microcomputer of controller 40 can be given RLY1_C high level signal, controls the first triode QR1 and ends to control the first relay R LY1 disconnection.Wherein, if the first relay R LY1 is normal, heater 1 disconnects with the first relay R LY1 that to cut off with power supply be being connected of electric main.Merge if contact occurs the first relay R LY1, no longer controlled and disconnect, now current transformer T1 detects that the operating current of heater 1 is greater than preset value, signaling conversion circuit 50 converts current signal to digital signal I_Detect, detect I_Detect signal, if be greater than 3.5V, prove that the first relay R LY1 occurs extremely can not normally disconnect, this Time Controller 40 for example single-chip microcomputer to RLY2_C low level signal, being used for controlling the second triode QR2 conducting disconnects to control normally closed relay RLY2, thereby cut-out heater 1 is connected with power supply.
Therefore; the safety protective circuit of the microwave oven of the present embodiment by increasing current transformer and normally closed relay on the loop of heater; utilize current transformer to detect on the loop of heater whether have operating current; whether merge the contact that judges the first relay; if the power supply that just disconnects cutting off heater by controlling normally closed relay is merged in the contact of the first relay; the potential safety hazard that prevents heater superheated and bring, realizes the safety protection function of microwave oven.
According to another embodiment of the present utility model, as shown in Figure 3, safety protection switch unit 30 comprises: the second relay R LY3 and the 3rd triode QR3.Switch in the second relay R LY3 is connected between the zero line N and live wire L of described electric main, one end ground connection of the coil in the second relay R LY3; The collector electrode of the 3rd triode QR3 is connected with the other end of the coil in the second relay R LY3, and the base stage of the 3rd triode QR3 is connected with controller 40, and the emitter of the 3rd triode QR3 is connected with the power supply of for example 12V of predeterminated voltage.Wherein, in the time that described operating current is greater than described preset value, controller 40 is controlled the 3rd triode QR3 conducting to control the second relay R LY3 closure, so that described electric main short circuit is connected on the fuse F1 on live wire L with fusing, thereby cuts off the electric main that is input to heater 1.
That is to say, in the present embodiment, as shown in Figure 3, after cooking in microwave oven finishes, for example single-chip microcomputer of controller 40 can be given RLY1_C high level signal, controls the first triode QR1 and ends to control the first relay R LY1 disconnection.Wherein, if the first relay R LY1 is normal, heater 1 disconnects with the first relay R LY1 that to cut off with power supply be being connected of electric main.Merge if contact occurs the first relay R LY1, no longer controlled and disconnect, now current transformer T1 detects that the operating current of heater 1 is greater than preset value, signaling conversion circuit 50 converts current signal to digital signal I_Detect, detect I_Detect signal, if be greater than 3.5V, prove that the first relay R LY1 occurs extremely can not normally disconnect, this Time Controller 40 for example single-chip microcomputer to RLY3_C low level signal, be used for controlling the 3rd triode QR2 conducting to control the second relay R LY3 closure, make electric main short circuit, thereby the fuse F1 that makes to be connected on live wire L disconnects, and then cut off being connected of heater 1 and for example electric main of power supply.
In embodiment of the present utility model, the first relay R LY1 and the second relay R LY2 are normally opened relay.Heater 1 comprises but only limits to the devices such as magnetron, barbecue heat-generating pipe, hot air convection.
According to the safety protective circuit of the microwave oven of the utility model embodiment, detect by increase heater operating current current detector and be connected to electric main and heater between safety protection switch unit judge whether the first switch element exists extremely, if existing the first relay in abnormal for example the first switch element that contact occurs, the first switch element merges, controller cuts off by controlling safety protection switch unit the electric main that is input to heater, prevent heater continuous firing and potential safety hazard that superheated causes food to burn and brings, realize the safety protection function of microwave oven, ensure that microwave oven safety is used reliably, meet user's demand.
In addition, embodiment of the present utility model has also proposed a kind of microwave oven, and it comprises the safety protective circuit of above-mentioned microwave oven.
According to the microwave oven of the utility model embodiment, in the time of end of cooking or time-out, control the first switch element and disconnect cutting off the electric main that is input to heater, if now detect that the operating current of heater is greater than preset value, illustrate that the first switch element does not disconnect, represent that the first switch element exists the first relay in abnormal for example the first switch element that contact fusion occurs, cut off by controlling safety protection switch unit the electric main that is input to heater, thereby prevent heater continuous firing and potential safety hazard that superheated causes food to burn and brings, realize safety protection function.Therefore, the microwave oven of the utility model embodiment can use safely and reliably, meets user's demand.
Fig. 4 is according to the flow chart of the safety protection control method of the microwave oven of the utility model embodiment.Wherein, this microwave oven is the microwave oven that above-described embodiment is described, and it comprises above-mentioned safety protective circuit.As shown in Figure 4, the safety protection control method of this microwave oven comprises the following steps:
S1, after cooking in microwave oven finishes or suspends, the first switch element in the safety protective circuit of control microwave oven disconnects.
S2, the operating current of the heater of detection microwave oven.
S3, in the time that operating current is greater than preset value, controls to cut off to the safety protection switch unit in safety protective circuit the electric main that is input to heater.
According to an embodiment of the present utility model, in the time that described safety protection switch unit comprises normally closed relay, disconnect cutting off by controlling described normally closed relay the electric main that is input to described heater.Particularly, after cooking in microwave oven finishes or suspends, for example single-chip microcomputer of controller calls safeguard protection subprogram, and as shown in Figure 5, the flow process of this safeguard protection subprogram is:
S501, after cooking in microwave oven finishes or suspends, single-chip microcomputer detects digital signal I_Detect, reads I_Detect signal.
S502, judges whether I_Detect signal is high level, and whether I_Detect signal equals 1.If so, perform step S503; If not, judge that the first relay R LY1 is normal, directly return to main program.
S503，RLY2_C＝0。That is to say, if high level judges that the first relay R LY1 contact occurs extremely for example to occur and merges, provide the instruction of opening RLY2, and return to main program.I.e. speech, single-chip microcomputer is to signal RLY2_C low level, the second triode QR2 conducting, normally closed relay RLY2 disconnects, thereby cuts off the power supply of heater, and heater stop heating realizes the safety protection function of microwave oven.
According to another embodiment of the present utility model; in the time that described safety protection switch unit comprises the second relay; so that described electric main short circuit is connected on the fuse on the live wire of described electric main with fusing, cut off the electric main that is input to described heater by controlling described the second relay closes.
According to the safety protection control method of the microwave oven of the utility model embodiment, in the time that cooking in microwave oven finishes or suspend, control the first switch element and disconnect cutting off the electric main that is input to heater, and detect the operating current of heater, if now detect that the operating current of heater is greater than preset value, illustrate that the first switch element does not disconnect, represent that the first switch element exists the first relay in abnormal for example the first switch element that contact fusion occurs, cut off by controlling safety protection switch unit the electric main that is input to heater, thereby prevent heater continuous firing and potential safety hazard that superheated causes food to burn and brings, realize the safety protection function of microwave oven, microwave oven can be used safely and reliably, meet user's demand.
Any process of otherwise describing in flow chart or at this or method are described and can be understood to, represent to comprise that one or more is for realizing the module of code of executable instruction of step of specific logical function or process, fragment or part, and the scope of preferred implementation of the present utility model comprises other realization, wherein can be not according to order shown or that discuss, comprise according to related function by the mode of basic while or by contrary order, carry out function, this should be understood by embodiment person of ordinary skill in the field of the present utility model.
The logic and/or the step that in flow chart, represent or otherwise describe at this, for example, can be considered to the sequencing list of the executable instruction for realizing logic function, may be embodied in any computer-readable medium, use for instruction execution system, device or equipment (as computer based system, comprise that the system of processor or other can and carry out the system of instruction from instruction execution system, device or equipment instruction fetch), or use in conjunction with these instruction execution systems, device or equipment.With regard to this specification, " computer-readable medium " can be anyly can comprise, device that storage, communication, propagation or transmission procedure use for instruction execution system, device or equipment or in conjunction with these instruction execution systems, device or equipment.The example more specifically (non-exhaustive list) of computer-readable medium comprises following: the electrical connection section (electronic installation) with one or more wirings, portable computer diskette box (magnetic device), random access memory (RAM), read-only memory (ROM), the erasable read-only memory (EPROM or flash memory) of editing, fiber device, and portable optic disk read-only memory (CDROM).In addition, computer-readable medium can be even paper or other the suitable medium that can print described program thereon, because can be for example by paper or other media be carried out to optical scanner, then edit, decipher or process in electronics mode and obtain described program with other suitable methods if desired, be then stored in computer storage.
Should be appreciated that each several part of the present utility model can realize with hardware, software, firmware or their combination.In the above-described embodiment, multiple steps or method can realize with being stored in software or the firmware carried out in memory and by suitable instruction execution system.For example, if realized with hardware, the same in another embodiment, can realize by any one in following technology well known in the art or their combination: there is the discrete logic for data-signal being realized to the logic gates of logic function, there is the application-specific integrated circuit (ASIC) of suitable combinational logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA) etc.
Those skilled in the art are appreciated that realizing all or part of step that above-described embodiment method carries is can carry out the hardware that instruction is relevant by program to complete, described program can be stored in a kind of computer-readable recording medium, this program, in the time carrying out, comprises step of embodiment of the method one or a combination set of.
In addition, the each functional unit in each embodiment of the utility model can be integrated in a processing module, can be also that the independent physics of unit exists, and also can be integrated in a module two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, and also can adopt the form of software function module to realize.If described integrated module realizes and during as production marketing independently or use, also can be stored in a computer read/write memory medium using the form of software function module.
The above-mentioned storage medium of mentioning can be read-only memory, disk or CD etc.
In the description of this specification, the description of reference term " embodiment ", " some embodiment ", " example ", " concrete example " or " some examples " etc. means to be contained at least one embodiment of the present utility model or example in conjunction with specific features, structure, material or the feature of this embodiment or example description.In this manual, the schematic statement of above-mentioned term is not necessarily referred to identical embodiment or example.And specific features, structure, material or the feature of description can be with suitable mode combination in any one or more embodiment or example.
Although illustrated and described embodiment of the present utility model, for the ordinary skill in the art, be appreciated that in the situation that not departing from principle of the present utility model and spirit and can carry out multiple variation, amendment, replacement and modification to these embodiment, scope of the present utility model is by claims and be equal to and limit.
Claims (7)
1. a safety protective circuit for microwave oven, is characterized in that, comprising:
For detection of the current detector of the operating current of the heater of described microwave oven;
The first switch element that is input to described heater for controlling electric main, described the first switch element is connected between described electric main and described heater;
Safety protection switch unit, described safety protection switch unit is connected between described electric main and described heater;
Controller; described controller is connected with described current detector, described the first switch element and described safety protection switch unit; wherein; after described in described controller control, the first switch element disconnects; if described current detector detects described operating current and be greater than preset value, described controller controls to cut off to described safety protection switch unit the electric main that is input to described heater.
2. the safety protective circuit of microwave oven as claimed in claim 1; it is characterized in that; when described current detector is current transformer; the primary side of described current transformer is connected on the zero line or live wire of described electric main, and described safety protective circuit also comprises the signaling conversion circuit being connected with the secondary side of described current transformer.
3. the safety protective circuit of microwave oven as claimed in claim 2, is characterized in that, described signaling conversion circuit comprises:
The first resistance, one end of described the first resistance is connected with one end of the secondary side winding of described current transformer;
The first diode, the anode of described the first diode is connected with the other end of described secondary side winding, and the negative electrode of described the first diode is connected with the other end of described the first resistance;
The first electric capacity, described the first electric capacity is in parallel with described the first resistance;
The second electric capacity, ground connection after one end of described the second electric capacity is connected with one end of described the first electric capacity;
The second resistance, one end of described the second resistance is connected with the other end of described the first electric capacity, after the other end of described the second resistance is connected with the other end of described the second electric capacity, is connected with described controller.
4. the safety protective circuit of the microwave oven as described in any one in claim 1-3, is characterized in that, described the first switch element comprises:
The first relay, the switch series in described the first relay is associated on the zero line or live wire of described electric main, one end ground connection of the coil in described the first relay;
The first triode, the collector electrode of described the first triode is connected with the other end of the coil in described the first relay, and the base stage of described the first triode is connected with described controller, and the emitter of described the first triode is connected with the power supply of predeterminated voltage.
5. the safety protective circuit of microwave oven as claimed in claim 4, is characterized in that, described safety protection switch unit comprises:
Normally closed relay, the switch series in described normally closed relay is associated on the zero line or live wire of described electric main, one end ground connection of the coil in described normally closed relay;
The second triode, the collector electrode of described the second triode is connected with the other end of the coil in described normally closed relay, and the base stage of described the second triode is connected with described controller, and the emitter of described the second triode is connected with the power supply of described predeterminated voltage;
Wherein, in the time that described operating current is greater than described preset value, the second triode conducting disconnects to control described normally closed relay described in described controller control, to cut off the electric main that is input to described heater.
6. the safety protective circuit of microwave oven as claimed in claim 4, is characterized in that, described safety protection switch unit comprises:
The second relay, the switch in described the second relay is connected between the zero line and live wire of described electric main, one end ground connection of the coil in described the second relay;
The 3rd triode, the collector electrode of described the 3rd triode is connected with the other end of the coil in described the second relay, and the base stage of described the 3rd triode is connected with described controller, and described the 3rd emitter of triode and the power supply of described predeterminated voltage are connected;
Wherein, in the time that described operating current is greater than described preset value, described in described controller control, the 3rd triode conducting, to control described the second relay closes, so that described electric main short circuit is connected on the fuse on described live wire with fusing, is cut off the electric main that is input to described heater.
7. a microwave oven, is characterized in that, comprises the safety protective circuit of the microwave oven as described in any one in claim 1-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420423598.0U CN204012659U (en) | 2014-07-29 | 2014-07-29 | Microwave oven and safety protective circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420423598.0U CN204012659U (en) | 2014-07-29 | 2014-07-29 | Microwave oven and safety protective circuit thereof |
Publications (1)
| Publication Number | Publication Date |
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| CN204012659U true CN204012659U (en) | 2014-12-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420423598.0U Withdrawn - After Issue CN204012659U (en) | 2014-07-29 | 2014-07-29 | Microwave oven and safety protective circuit thereof |
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| Country | Link |
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| CN (1) | CN204012659U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104104059A (en) * | 2014-07-29 | 2014-10-15 | 广东美的厨房电器制造有限公司 | Microwave oven, safety protection circuit and safety protection control method thereof |
| CN108460923A (en) * | 2018-04-25 | 2018-08-28 | 北京七十五度科技有限公司 | A kind of the food heating vending machine and heating means of distributed heating |
-
2014
- 2014-07-29 CN CN201420423598.0U patent/CN204012659U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104104059A (en) * | 2014-07-29 | 2014-10-15 | 广东美的厨房电器制造有限公司 | Microwave oven, safety protection circuit and safety protection control method thereof |
| CN104104059B (en) * | 2014-07-29 | 2017-04-05 | 广东美的厨房电器制造有限公司 | Micro-wave oven and its safety protective circuit and safety protection control method |
| CN108460923A (en) * | 2018-04-25 | 2018-08-28 | 北京七十五度科技有限公司 | A kind of the food heating vending machine and heating means of distributed heating |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141210 Effective date of abandoning: 20170405 |
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| AV01 | Patent right actively abandoned |