All-line same-effect limit overheat out-of-control and anti-electric-shock heat control circuit

Abstract

The utility model relates to a whole-line same-effect overheat-limiting out-of-control-prevention electric shock-prevention heat control circuit, which adopts the technical scheme that two ends of a voltage stabilizing diode WD2, a discharge tube TSS and a current limiting circuit (a constant current diode HL is connected with an inductor LK in series with a resistor R2) are connected between the VS1 end and the VS2 end of a core module IC1, and the input ends Vi1 and Vi2 of the module IC1 are connected with the ends a and b of the secondary n3 of a mutual inductor H through a resistor R6; a voltage stabilizing diode WD1, a capacitor C1 and two ends of a relay coil JX are connected between output ends VOT and VOL of the module IC1, two groups of normally open contacts JK of a relay respectively control two poles of alternating current power supplies of load lines L1, N1, L2 and N2, a thermosensitive diaphragm RGM is clamped between electric heating wires RTX1 and RTX2, ends b and c of the electric heating wires are connected, and ends a and d of the electric heating wires are respectively connected with the load lines L2 and N2. Therefore, the device has high-safety effects and technical advantages of whole-line same-effect limit overheat, out-of-control prevention and electric shock prevention.

Description

Technical Field

[0001] The utility model belongs to the technical field of temperature control of electric heating appliances, and particularly relates to a heat control circuit with the same effect of limiting overheating, preventing runaway and preventing electric shock throughout the entire line. It can not only automatically control the temperature of the electric heating wire in the appliance and effectively prevent overheating hazards, but also achieve the same overheating limiting effect or consistent overheating protection control sensitivity throughout the entire electric heating wire, prevent high heat runaway from causing fires in the event of a fault, and prevent electric shock accidents caused by leakage in the electric heating wire and its load line. Therefore, the utility model allows the temperature control or heat control circuit to have a complete safety protection function and effect, and is particularly suitable for high-quality requirements that require certain safe temperature control. Background Art

[0002] The existing temperature control circuits on the market have only simple local point temperature control functions. The overheating limiting effects of different parts of large electric heating elements or long electric heating wires vary greatly, or the sensitivity of overheat protection control is inconsistent. Fires are caused by high-temperature runaway due to failures. The insulation strength of electric heating elements or electric heating wires is aged rapidly under high temperature for a long time, which will also lead to increased leakage and easily cause electric shock accidents. If a special leakage protector is separately connected to the AC power supply end, it will not only increase the cost, but also the traditional leakage protector will have the chance of failure. Therefore, the existing temperature control circuits on the market have serious defects and safety hazards, which may be safety technical problems that are not valued or difficult to solve in this technical field.

[0003] Perfecting and solving safety technology problems, completely eliminating safety hazards and defects, and ensuring that the entire thermal control circuit effectively limits overheating, prevents runaway and prevents electric shock, thereby achieving the technical requirements for safe thermal control, is necessary to meet users' high safety requirements for electric heating appliances, and is also the responsibility and opportunity for innovative development of the electric heating appliance research and development and manufacturing industry. Summary of the invention

[0004] The purpose of the utility model is to design a heat control circuit that is absolutely safe and can effectively limit overheating, prevent runaway and prevent electric shock throughout the entire line, completely eliminate the serious defects and safety hazards existing in existing temperature control circuits on the market, and perfectly solve safety technical problems, so that the heat control circuit has complete safety protection functions and effects, thereby meeting the technical requirements of absolutely safe heat control.

[0005] In order to achieve the above objectives and solve the above technical problems, the utility model adopts the following technical solutions:

[0006] A full-line thermal control circuit with the same effect of limiting overheating, preventing runaway and preventing electric shock, and its technical solution is as follows Figure 1As shown, it includes a fuse RD1, a start button QD, a protection switch and its control circuit, and a varistor MOV, and is characterized in that it also includes an overheat current limiting circuit, a protection function test circuit, a zero-sequence current transformer H, a signal processing circuit, a core circuit module IC1, an AC power supply overvoltage protection circuit, electric heating wires RTX1 and RTX2, and a thermal diaphragm RGM; the protection switch and its control circuit include a diode D1, a voltage-stabilizing diode WD1, a capacitor C1, an adjustable resistor Rf, and a relay, and the relay is composed of an electromagnetic coil J X And two sets of normally open contacts J K The overheat current limiting circuit includes an inductor LK and a bidirectional constant current diode HL, or only one of the two is selected, and the unused two ends are directly short-circuited and then cancelled. The protection function test circuit includes resistors R1 and R4, test buttons SA1 and SA2, and the zero-sequence current transformer H is composed of primary coils n1 and n2 and secondary coil n3 and a magnetic ring. The signal processing circuit includes a voltage-stabilizing diode WD6, a resistor R6, and a capacitor C6. The core circuit module IC1 adopts a fixed-effect leakage prevention safety control circuit HLBA9168 or a circuit with equivalent functions. The AC power supply overvoltage protection circuit includes an AC voltage-stabilizing diode WD2 and a bidirectional discharge diode TSS Or a varistor, a capacitor C2, and a resistor R2; its circuit connection mode: the primary coils n1 and n2 of the zero-sequence current transformer H are wound in parallel and the secondary coil n3 is wound alone on the same magnetic ring, wherein the primary coil n1 is connected in series between the inductor LK and the bidirectional constant-current diode HL, the other end of the inductor LK is connected to the AC load line L1, the other end of the bidirectional constant-current diode HL is connected to the AC load line L2, the primary coil n2 is connected in series between the AC load lines N1 and N2, the a end of the secondary coil n3 is connected to the positive electrode of the voltage-stabilizing diode WD6 and one end of the resistor R6, the other end of the resistor R6 and the negative electrode of the voltage-stabilizing diode WD6 and one end of the capacitor C6 are connected to the external signal positive input terminal (V i1 ) or external signal AC input terminal (V i3 ), the b end of the secondary coil n3 is directly connected to the negative input end of the external signal of the core circuit module IC1 (V i2 ) and the other end of capacitor C6; the left input terminal V of the AC power supply of the core circuit module IC1 S1 Connect one end of the AC voltage stabilizing diode WD2 to one end of the bidirectional discharge diode TSS and one end of the capacitor C2 and the AC load line L2, and the AC power supply right input terminal V S2 Connect the other end of the AC voltage stabilizing diode WD2 to the other end of the bidirectional discharge diode TSS and the other end of the capacitor C2 and one end of the resistor R2. The other end of the resistor R2 is connected to the AC load line L1. The positive electrode (V OT) Connect the cathode of the voltage stabilizing diode WD1 and the anode of the capacitor C1 to one end of the adjustable resistor Rf, and the other end of the adjustable resistor Rf to the cathode of the diode D1 and the relay coil J X One end, relay coil J X The other end and the anode of diode D1, the anode of voltage stabilizing diode WD1, and the cathode of capacitor C1 are connected in parallel to the cathode of the core circuit module IC1 (V OL ), a group of normally open contacts J in the relay K The two ends of the relay are connected between one end of the fuse RD1 and the AC load line L1. K The two ends of the fuse RD1 are separately connected between the AC power input terminal N and the AC load line N1, and the other end of the fuse RD1 is connected to the AC power input terminal L; the two ends of the varistor MOV are separately connected between the AC load lines L1 and N1; the two ends of the normally open contact in the test button SA1 are respectively connected between the AC load line L2 and one end of the resistor R1, and the other end of the resistor R1 is connected to the AC load line L1; press the start button QD, the AC power input terminal L is connected to the AC load line L1, and at the same time, the AC power input terminal N is connected to the AC load line N1 Therefore, there is AC power output between the AC load line L2 and N2, the AC load line L2 is connected to the a-end of the heating wire RTX1, the b-end of the heating wire RTX1 is connected to the c-end of the heating wire RTX2 and one end of the resistor R4, the d-end of the heating wire RTX2 is connected to the AC load line N2 and one end of the test button SA2, the other end of the test button SA2 is connected to the other end of the resistor R4, and a thermistor diaphragm RGM is sandwiched between the heating wires RTX1 and RTX2. The thermistor diaphragm RGM has the characteristics of a negative temperature coefficient thermistor, so it has an anti-overheating protection function.

[0007] Since the basic working principle of the technical solution used in the utility model is: two parallel electric heating wires with a thermosensitive diaphragm are energized in series, and then a current limiting shunt circuit is connected in series on the power supply side to convert the shunt current into the residual current of the zero-sequence current transformer H, and then the residual current signal is detected by the leakage protection circuit. When the temperature of the two electric heating wires is too high or the heat is too high, the leakage current of the thermosensitive diaphragm is too large, which will make the shunt current too large and convert it into a residual current signal exceeding the set upper limit, triggering the leakage protection circuit to disconnect the power supply. Therefore, the leakage protection circuit also has the function of temperature control at the same time. Kill two birds with one stone.

[0008] Therefore, the beneficial effects and technical advantages of the utility model are:

[0009] It can not only automatically control the temperature of the entire thread of the heating wire to avoid overheating hazards, but also achieve the same overheating limitation effect or consistent overheating protection control sensitivity at all points of the entire thread of the heating wire, small impact current when the heating wire is overheated, and prevent high-temperature runaway and fire in the event of a fault. It can also prevent electric shock accidents caused by leakage of the heating wire and its load line. Therefore, the utility model allows the temperature control or heat control circuit to have a complete safety protection function and effect, without safety hazards and defects, thereby meeting the technical requirements of certain safe heat control, and is particularly suitable for high-quality requirements that require certain safe temperature control. And the cost is low and the cost performance is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The utility model is a heat control circuit schematic diagram of the utility model or a full-line same-effect overheating-limiting, runaway-prevention and electric shock-prevention. DETAILED DESCRIPTION

[0011] The technical solution of the utility model is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0012] 1. Yes Figure 1 Detailed description of the technical solution:

[0013] Figure 1 The utility model or a full-line heat control circuit schematic diagram of the same effect of limiting overheating, preventing runaway and preventing electric shock, includes a fuse RD1, a start button QD, a protection switch and its control circuit, and a varistor MOV, and is characterized in that it also includes an overheat current limiting circuit, a protection function test circuit, a zero-sequence current transformer H, a signal processing circuit, a core circuit module IC1, an AC power supply overvoltage protection circuit, electric heating wires RTX1 and RTX2, and a thermal diaphragm RGM; the protection switch and its control circuit include a diode D1, a voltage regulator diode WD1, a capacitor C1, an adjustable resistor Rf, and a relay, and the relay is composed of an electromagnetic coil J X And two sets of normally open contacts J KThe overheat current limiting circuit includes an inductor LK and a bidirectional constant current diode HL, or only one of the two is selected, and the unused two ends are directly short-circuited and then cancelled. The protection function test circuit includes resistors R1 and R4, test buttons SA1 and SA2, and the zero-sequence current transformer H is composed of primary coils n1 and n2 and secondary coil n3 and a magnetic ring. The signal processing circuit includes a voltage-stabilizing diode WD6, a resistor R6, and a capacitor C6. The core circuit module IC1 adopts a fixed-effect leakage prevention safety control circuit HLBA9168 or a circuit with equivalent functions. The AC power supply overvoltage protection circuit includes an AC voltage-stabilizing diode WD2 and a bidirectional discharge diode TSS Or a varistor, a capacitor C2, and a resistor R2; its circuit connection mode: the primary coils n1 and n2 of the zero-sequence current transformer H are wound in parallel and the secondary coil n3 is wound alone on the same magnetic ring, wherein the primary coil n1 is connected in series between the inductor LK and the bidirectional constant-current diode HL, the other end of the inductor LK is connected to the AC load line L1, the other end of the bidirectional constant-current diode HL is connected to the AC load line L2, the primary coil n2 is connected in series between the AC load lines N1 and N2, the a end of the secondary coil n3 is connected to the positive electrode of the voltage-stabilizing diode WD6 and one end of the resistor R6, the other end of the resistor R6 and the negative electrode of the voltage-stabilizing diode WD6 and one end of the capacitor C6 are connected to the external signal positive input terminal (V i1 ) or external signal AC input terminal (V i3 ), the b end of the secondary coil n3 is directly connected to the negative input end of the external signal of the core circuit module IC1 (V i2 ) and the other end of capacitor C6; the left input terminal V of the AC power supply of the core circuit module IC1 S1 Connect one end of the AC voltage stabilizing diode WD2 to one end of the bidirectional discharge diode TSS and one end of the capacitor C2 and the AC load line L2, and the AC power supply right input terminal V S2 Connect the other end of the AC voltage stabilizing diode WD2 to the other end of the bidirectional discharge diode TSS and the other end of the capacitor C2 and one end of the resistor R2. The other end of the resistor R2 is connected to the AC load line L1. The positive electrode (V OT ) Connect the cathode of the voltage stabilizing diode WD1 and the anode of the capacitor C1 to one end of the adjustable resistor Rf, and the other end of the adjustable resistor Rf to the cathode of the diode D1 and the relay coil J X One end, relay coil J X The other end and the anode of diode D1, the anode of voltage stabilizing diode WD1, and the cathode of capacitor C1 are connected in parallel to the cathode of the core circuit module IC1 (V OL ), a group of normally open contacts J in the relay K The two ends of the relay are connected between one end of the fuse RD1 and the AC load line L1. KThe two ends of the fuse RD1 are separately connected between the AC power input terminal N and the AC load line N1, and the other end of the fuse RD1 is connected to the AC power input terminal L; the two ends of the varistor MOV are separately connected between the AC load lines L1 and N1; the two ends of the normally open contact in the test button SA1 are respectively connected between the AC load line L2 and one end of the resistor R1, and the other end of the resistor R1 is connected to the AC load line L1; press the start button QD, the AC power input terminal L is connected to the AC load line L1, and at the same time, the AC power input terminal N is connected to the AC load line N1 Therefore, there is AC power output between the AC load line L2 and N2, the AC load line L2 is connected to the a-end of the heating wire RTX1, the b-end of the heating wire RTX1 is connected to the c-end of the heating wire RTX2 and one end of the resistor R4, the d-end of the heating wire RTX2 is connected to the AC load line N2 and one end of the test button SA2, the other end of the test button SA2 is connected to the other end of the resistor R4, and a thermistor diaphragm RGM is sandwiched between the heating wires RTX1 and RTX2. The thermistor diaphragm RGM has the characteristics of a negative temperature coefficient thermistor, so it has an anti-overheating protection function.

[0014] two, Figure 1 The circuit works as follows:

[0015] Overheating limit principle: After pressing the start button QD, the two sets of normally open contacts J of the relay K Close, connect the AC power on the AC power input terminals L and N to the AC load lines L1 and N1. On the one hand, it is transmitted to the AC load lines L2 and N2 through the primary coils n1 and n2 of the zero-sequence current transformer H, so that the heating wires RTX1 and RTX2 begin to heat up through the AC current. On the other hand, the AC power input terminal V S1 and V S2 The AC power supply is obtained from the AC load lines L1 and L2, and the output terminal V OT and V OL Output DC voltage to make the relay's electromagnetic coil J X The AC power source obtained on the AC load lines L2 and N2 is locked, so that the heating wires RTX1 and RTX2 continue to flow with current and generate heat. i1 and V i2 When there is no leakage signal input, the output terminal V OT and V OLThe DC voltage is continuously output, and the relay continues to lock the heating wires RTX1 and RTX2 to continue to pass current and generate heat. If the heat dissipation is small, the temperature will rise, and the leakage of the thermistor diaphragm RGM between the heating wires RTX1 and RTX2 will increase with the temperature. Since the voltages borne by the a-end to the c-end, the b-end to the d-end, and the corresponding points in the middle of the two wires of the heating wires RTX1 and RTX2 are the same (approximately half of the power supply voltage), the material thickness and impedance characteristics of the middle thermistor diaphragm RGM are basically the same, then the leakage current of the middle thermistor diaphragm at all points of the entire heating wire RTX1 and RTX2 at the same temperature should also be roughly the same, so the overheating protection control sensitivity or overheating limiting effect at all points of the entire heating wire thread should also be roughly the same, thus achieving the effect of limiting overheating with the same effect on the entire line. If the test button SA2 is pressed manually, it is equivalent to simulating that the temperature of the controlled heating wires RTX1 and RTX2 is too high or exceeds the heat. During this period, the thermistor diaphragm RGM has a large leakage, which is equivalent to increasing the current passing through the heating wire RTX2 and the primary coils n1 and n2 of the zero-sequence current transformer H, increasing the voltage drop on the inductor LK and the bidirectional constant current diode HL, and increasing the current passing through the shunt circuit (resistor R2 in series with the AC voltage regulator diode WD2). An unbalanced AC current (equivalent to generating a residual current) will pass through the primary coils n1 and n2 of the zero-sequence current transformer H. The residual current generates an induced magnetic flux in the iron core of the zero-sequence current transformer H, causing an induced AC current or voltage signal to be generated at both ends of the secondary coil n3. If the intensity of this voltage signal exceeds the set value, the capacitor C6 will be charged and accumulated multiple times through the voltage regulator diode WD6, causing the potential product at both ends of the capacitor C6 to rise, which will trigger the signal input terminal (V i1 and V i2 ) The positive and negative electrodes inside the lock unit circuit lock and cut off the subsequent control current, turn off the push-pull drive current, and make the output terminal V of the core circuit module IC1 OT and V OL The driving voltage between them disappears, allowing the external relay coil J X Loss of power releases two pairs of normally open contacts J K , the AC power supply must be cut off and the power-off state will be maintained all the time, and the power cannot be restored without human intervention. Therefore, the safety protection control of the over-temperature or over-heat of the heating wires RTX1 and RTX2 can be realized.

[0016] Anti-runaway principle: According to the principle of this technical solution, it can be predicted that: (a) if the two input terminals (V i1 、V i2 ) or the AC power input of the core circuit module IC1 (V S1 、V S2 ) between the positive pole of the output (V OT ) and the negative electrode (V OL), or the protection switch and its control circuit, any open circuit or short circuit will cause the relay to cut off the power for safety protection; (ii) if the varistor MOV is short-circuited, it will inevitably cause the core circuit module IC1 to lose power and cause the relay to cut off the power for safety protection; (iii) if any of the current paths in series, such as the heating wires RTX1 and RTX2, the inductor LK and the bidirectional constant current diode HL, are open-circuited or short-circuited, the AC power input ends (V S1 、V S2 ) between the input voltage disappears, making the output terminal V OT and V OL The driving voltage between them disappears, allowing the external relay coil J X Loss of power releases two pairs of normally open contacts J K , the AC power supply must be cut off to achieve the functional effect of preventing fault runaway, avoid fire caused by temperature runaway, and ensure absolute safety.

[0017] Anti-electric shock principle: If the test button SA1 is pressed manually, the current passing through the inductor LK, the bidirectional constant current diode HL and the primary coil n1 of the zero-sequence current transformer H will be shunted by the resistor R1, which is equivalent to simulating the leakage or electric shock of the controlled AC load lines L2 and N2 or the heating wires RTX1 and RTX2 to the ground. An unbalanced AC current (equivalent to residual current) passes through the primary coils n1 and n2 of the zero-sequence current transformer H. The residual current generates an induced magnetic flux in the iron core of the zero-sequence current transformer H, so that an induced AC current or voltage signal is generated at both ends of the secondary coil n3. If the voltage intensity of this signal exceeds the set value, the capacitor C6 is charged and accumulated multiple times through the voltage stabilizing diode WD6, so that the potential product at both ends of the capacitor C6 rises, which will trigger the signal input terminal (V i1 and V i2 ) The positive and negative electrodes inside the lock unit circuit lock and cut off the subsequent control current, turn off the push-pull drive current, and make the output terminal V of the core circuit module IC1 OT and V OL The driving voltage between them disappears, allowing the external relay coil J X Loss of power releases two pairs of normally open contacts J K , the AC power supply must be cut off and maintained in a power-off state at all times. Power cannot be restored without human intervention, so that leakage or electric shock can be protected normally, allowing electricity users to avoid danger and ensure the safety of their lives.

[0018] visible, Figure 1The technical solution can not only automatically control the temperature of the entire thread of the heating wire and avoid overheating hazards, but also achieve the same overheating limitation effect or consistent overheating protection control sensitivity at all points on the entire thread of the heating wire, small impact current when the heating wire is overheated, and prevent high temperature runaway and fire in the event of a fault. It can also prevent electric shock accidents caused by leakage of the heating wire and its load lines, thereby meeting the technical requirements for certain safe heat control.

Claims

1. A full-line thermal control circuit with the same effect of limiting overheating, preventing runaway and preventing electric shock, including a fuse RD1, a start button QD, a protection switch and its control circuit, and a varistor MOV, characterized in that: It also includes an overheat current limiting circuit, a protection function test circuit, a zero-sequence current transformer H, a signal processing circuit, a core circuit module IC1, an AC power supply overvoltage protection circuit, electric heating wires RTX1 and RTX2, and a thermal diaphragm RGM; the protection switch and its control circuit include a diode D1, a voltage-stabilizing diode WD1, a capacitor C1, an adjustable resistor Rf, and a relay, wherein the relay is composed of an electromagnetic coil J X And two sets of normally open contacts J K The overheat current limiting circuit includes an inductor LK and a bidirectional constant current diode HL, or only one of the two is selected, and the unused two ends are directly short-circuited and then cancelled. The protection function test circuit includes resistors R1 and R4, test buttons SA1 and SA2, and the zero-sequence current transformer H is composed of primary coils n1 and n2 and secondary coil n3 and a magnetic ring. The signal processing circuit includes a voltage-stabilizing diode WD6, a resistor R6, and a capacitor C6. The core circuit module IC1 adopts a fixed-effect leakage prevention safety control circuit HLBA9168 or a circuit with equivalent functions. The AC power supply overvoltage protection circuit includes an AC voltage-stabilizing diode WD2 and a bidirectional discharge diode TSS Or a varistor, a capacitor C2, and a resistor R2; its circuit connection mode: the primary coils n1 and n2 of the zero-sequence current transformer H are wound in parallel and the secondary coil n3 is wound alone on the same magnetic ring, wherein the primary coil n1 is connected in series between the inductor LK and the bidirectional constant-current diode HL, the other end of the inductor LK is connected to the AC load line L1, the other end of the bidirectional constant-current diode HL is connected to the AC load line L2, the primary coil n2 is connected in series between the AC load lines N1 and N2, the a end of the secondary coil n3 is connected to the positive electrode of the voltage-stabilizing diode WD6 and one end of the resistor R6, the other end of the resistor R6 and the negative electrode of the voltage-stabilizing diode WD6 and one end of the capacitor C6 are connected to the external signal positive input terminal (V i1 ) or external signal AC input terminal (V i3 ), the b end of the secondary coil n3 is directly connected to the negative input end of the external signal of the core circuit module IC1 (V i2 ) and the other end of capacitor C6; the left input terminal V of the AC power supply of the core circuit module IC1 S1 Connect one end of the AC voltage stabilizing diode WD2 to one end of the bidirectional discharge diode TSS and one end of the capacitor C2 and the AC load line L2, and the AC power supply right input terminal V S2 Connect the other end of the AC voltage stabilizing diode WD2 to the other end of the bidirectional discharge diode TSS and the other end of the capacitor C2 and one end of the resistor R2. The other end of the resistor R2 is connected to the AC load line L1. The positive electrode (V OT ) Connect the cathode of the voltage stabilizing diode WD1 and the anode of the capacitor C1 to one end of the adjustable resistor Rf, and the other end of the adjustable resistor Rf to the cathode of the diode D1 and the relay coil J X One end, relay coil J X The other end and the anode of diode D1, the anode of voltage stabilizing diode WD1, and the cathode of capacitor C1 are connected in parallel to the cathode of the core circuit module IC1 (V OL ), a group of normally open contacts J in the relay K The two ends of the relay are connected between one end of the fuse RD1 and the AC load line L1. K The two ends of the test button SA1 are separately connected between the AC power input terminal N and the AC load line N1, and the other end of the fuse RD1 is connected to the AC power input terminal L; the two ends of the varistor MOV are separately connected between the AC load lines L1 and N1; the two ends of the normally open contact in the test button SA1 are respectively connected between the AC load line L2 and one end of the resistor R1, and the other end of the resistor R1 is connected to the AC load line L1; Press the start button QD, the AC power input terminal L is connected to the AC load line L1, and at the same time, the AC power input terminal N is connected to the AC load line N1, so there is AC power output between the AC load lines L2 and N2, the AC load line L2 is connected to the a end of the heating wire RTX1, the b end of the heating wire RTX1 is connected to the c end of the heating wire RTX2 and one end of the resistor R4, the d end of the heating wire RTX2 is connected to the AC load line N2 and one end of the test button SA2, the other end of the test button SA2 is connected to the other end of the resistor R4, and a thermistor RGM is sandwiched between the heating wires RTX1 and RTX2. The thermistor RGM has the characteristics of a negative temperature coefficient thermistor, so it has an anti-overheating protection function.

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