A temperature-controlled molded case circuit breaker overload alarm non-tripping device

Abstract

The present invention relates to a temperature-controlled molded case circuit breaker overload alarm non-tripping device, comprising a current output terminal, a static iron core and a thermal element are installed on the current output terminal, a thermal conductive insulating member is installed on the thermal element, a thermistor is installed in the thermal conductive insulating member, the thermistor is connected to a signal line, the signal line is connected to a controller, and the thermal element is connected to a soft connection. The present invention has a short-circuit protection function, a compact structure, and space saving. The temperature of the heating element is monitored in real time by temperature monitoring, and feedback is given on whether the main circuit current is overloaded, so as to ensure that the circuit breaker does not trip and accurately output an alarm signal.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal magnetic molded case circuit breakers, and relates to an overload alarm non-tripping device for a temperature-controlled molded case circuit breaker. Background Art

[0002] Generally speaking, the overload non-tripping function of thermal magnetic molded case circuit breakers is achieved by driving the signal conversion switch through the thermal bimetallic element to realize the alarm non-tripping function. There are many parts, the structure is relatively complex and it occupies a large space. Summary of the invention

[0003] The object of the present invention is to provide a temperature-controlled molded case circuit breaker overload alarm non-tripping device, which can solve the problems that the original device has more parts, a relatively complex structure and occupies a large space.

[0004] According to the technical solution provided by the present invention: a temperature-controlled molded case circuit breaker overload alarm non-tripping device includes a current output terminal, a static iron core and a thermal element are installed on the current output terminal, a thermal conductive insulating member is installed on the thermal element, a thermistor is installed in the thermal conductive insulating member, the thermistor is connected to a signal line, the signal line is connected to a controller, and the thermal element is connected to a soft connection.

[0005] As a further improvement of the present invention, the controller is installed on the circuit breaker housing.

[0006] As a further improvement of the present invention, the current output terminal and the static iron core are fixed by riveting with a first rivet.

[0007] As a further improvement of the present invention, the current output terminal and the thermal element are fixed by riveting with a second rivet.

[0008] As a further improvement of the present invention, the thermal element is connected to the flexible connection by welding.

[0009] As a further improvement of the present invention, the flexible connection is made of copper.

[0010] As a further improvement of the present invention, the thermally conductive insulating component is a ceramic component.

[0011] As a further improvement of the present invention, the thermally conductive insulating member is a thermally conductive silicone member.

[0012] As a further improvement of the present invention, the ceramic component includes a first ceramic sheet and a second ceramic sheet, both of which are semi-cavity structures, the thermal element is connected to the first ceramic sheet and the second ceramic sheet by screws, the thermistor is arranged in the cavity of the first ceramic sheet and the second ceramic sheet, and an outlet is opened on the side of the first ceramic sheet and the second ceramic sheet, one end of the signal line is connected to the thermistor, and the other end passes through the outlet to be connected to the controller.

[0013] The positive effects of this application are:

[0014] 1. The present invention has a short-circuit protection function, a compact structure and saves space.

[0015] 2. The present invention uses temperature monitoring to monitor the temperature of the heating element in real time, and feedback whether the main circuit current is overloaded, to ensure that the circuit breaker does not trip and accurately output an alarm signal.

[0016] 3. The present invention has reliable functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Figure 2 It is a schematic diagram of the structural assembly of the present invention.

[0019] Figure 3 4 is a circuit diagram of the controller of the present invention. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1-3 The invention comprises a current output terminal 1, a static iron core 2, a first rivet 3, a second rivet 4, a thermal element 5, a screw 6, a first ceramic sheet 7, a second ceramic sheet 8, a thermistor 9, a flexible connection 10, a signal line 11, a controller 12 and the like.

[0022] like Figure 1-2 As shown, the present invention is a temperature-controlled molded case circuit breaker overload alarm non-tripping device, including a current output terminal 1, the current output terminal 1 and the static iron core 2 are riveted and fixed by a first rivet 3, the current output terminal 1 and the thermal element 5 are riveted and fixed by a second rivet 4, a screw hole is provided on the thermal element 5, and the thermal element 5 is fastened to the first ceramic sheet 7 and the second ceramic sheet 8 by screws 6. A thermistor 9 is provided in the cavity formed at the lower end after the first ceramic sheet 7 and the second ceramic sheet 8 are fastened by screws 6. The thermistor 9 is connected to a signal line 11, and the signal line 11 is connected to a controller 12. The lower end of the thermal element 5 is connected to a soft connection (copper strip) 10 by welding. The controller 12 is mounted on the circuit breaker housing.

[0023] A temperature-controlled molded case circuit breaker overload alarm non-tripping device is welded to the main circuit of the molded case circuit breaker by a flexible connection 10. When the current in the circuit is not overloaded, the current enters the device through 10, and the current flows out from the current output terminal 1 through the thermal element 5. The current passes through the thermal element 5, and the thermal element 5 generates a small amount of heat, and the heat is conducted to the first ceramic sheet 7 and the second ceramic sheet 8 that are attached to the thermal element 5. The first ceramic sheet 7 and the second ceramic sheet 8 have good thermal conductivity and insulation properties. The thermistor 9 arranged in the lower end cavity of the first ceramic sheet 7 and the second ceramic sheet 8 outputs a temperature signal. It is conducted to the controller 12 through the signal line 11, and the temperature value at this time does not reach the set alarm temperature value. The controller 12 determines that the current in the circuit is not overloaded based on the signal and does not issue an alarm.

[0024] When the current in the current is overloaded, the current passes through the thermal element 5, causing the thermal element 5 to heat up, and the heat is conducted to the first ceramic sheet 7 and the second ceramic sheet 8 attached to the thermal element 5. The thermistor 9 arranged in the lower cavity of the first ceramic sheet 7 and the second ceramic sheet 8 outputs a temperature signal. The signal is conducted to the controller 12 through the signal line 11. At this time, the temperature value reaches the set alarm value. The controller 12 determines that the current in the circuit has been overloaded according to the temperature signal and immediately alarms.

[0025] When a short circuit occurs in the circuit, the static iron core 2 provides the magnetic field required for the moving iron core of the circuit breaker to operate.

[0026] like Figure 3 As shown, the circuit of the controller 12 of the present invention includes a first reference voltage circuit, a second reference voltage circuit, a resistor R3, a thermistor RP1, resistors R5, R8, an operational amplifier U1B, an operational amplifier U2A, a diode D3, an operational amplifier U2B, a resistor R12, an NPN transistor Q1, a diode D4, and a relay K1;

[0027] In this embodiment, the thermistor RP1 is a negative temperature coefficient thermistor;

[0028] One end of the resistor R3 is connected to the positive voltage VCC, and the other end is connected to one end of the resistor R5 and one end of the thermistor RP1, and the other end of the thermistor RP1 is grounded; the other end of the resistor R5 is connected to the inverting input end of the operational amplifier U1B and one end of the resistor R8, the output end of the operational amplifier U1B is connected to the other end of the resistor R8, and is connected to the non-inverting input end of the operational amplifier U2A through a forward-set diode D2 or directly; the non-inverting input end of the operational amplifier U1B is connected to the first reference voltage Vref1;

[0029] In this embodiment, the first reference voltage Vref1 is generated by a first reference voltage circuit; the first reference voltage circuit includes resistors R1, R2, an operational amplifier U1A, resistors R6, and R7; one end of the resistor R1 is connected to a positive voltage VCC, the other end is connected to one end of the resistor R2 and the non-inverting input end of the operational amplifier U1A, and the other end of the resistor R2 is grounded; the inverting input end of the operational amplifier U1A is connected to the output end of U1A and one end of the resistor R6, the other end of the resistor R6 is connected to one end of the resistor R7, and the first reference voltage Vref1 is obtained and connected to the non-inverting input end of the operational amplifier U1B; the other end of the resistor R7 is grounded;

[0030] The inverting input terminal of the operational amplifier U2A is connected to the second reference voltage Vref2, the output terminal of the operational amplifier U2A is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the non-inverting input terminal of the operational amplifier U2B;

[0031] In this embodiment, the second reference voltage Vref2 is generated by a second reference voltage circuit; the second reference voltage circuit includes resistors R9 and R10; one end of the resistor R10 is connected to the positive voltage VCC, and the other end is connected to one end of the resistor R9 to obtain the second reference voltage Vref2; the other end of the resistor R9 is grounded; the resistor R9 can use an adjustable potentiometer to obtain different comparison reference voltages, namely the second reference voltage Vref2, so that the circuit can be applied to circuit breaker products of different specifications;

[0032] The inverting input terminal of the operational amplifier U2B is connected to the second reference voltage Vref2; the output terminal of the operational amplifier U2B is connected to the base of the transistor Q1 through the resistor R12, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to one end of the coil of the relay K1 and the anode of the diode D4, and the other end of the coil of the relay K1 and the cathode of the diode D4 are connected to the positive voltage VDD;

[0033] The normally open contact of relay K1 is connected to terminal block J1;

[0034] The positive voltages VCC and VDD can be generated by a power supply circuit, which is a conventional circuit in the art and will not be described here.

[0035] Preferably, in this embodiment, a delay circuit is added, which includes a resistor R11 and a capacitor C3. One end of the resistor R11 is connected to the positive voltage VCC, and the other end is connected to one end of the capacitor C3 and the non-inverting input end of the operational amplifier U2B; the other end of the capacitor C3 is grounded.

[0036] In this embodiment, the control of the circuit breaker is implemented by fixing the thermistor RP1 on the heating element of the circuit breaker, and the resistance value of the thermistor RP1 will change in real time with the change of temperature; the resistors R1 and R2 divide the positive voltage VCC, and the divided voltage value is input to the voltage follower formed by the operational amplifier U1A; when the circuit breaker is not overloaded, the resistance value of the thermistor RP1 is large, the voltage on it is large, the operational amplifier U1B outputs a low voltage, the operational amplifier U2A also outputs a low voltage, then the diode D3 is turned on, the voltage at the in-phase input terminal of the operational amplifier U2B is pulled down, the operational amplifier U2B also outputs a low voltage, the transistor Q1 will not be turned on, and the relay K1 will not be attracted; the terminal block J1 does not output an alarm signal;

[0037] When the circuit breaker generates heat due to overload, the resistance of the thermistor RP1 decreases, and the voltage on it becomes smaller. When the circuit breaker temperature is greater than the set reference, the operational amplifier U1B reverses and outputs a high level, then the operational amplifier U2A also outputs a high level, the diode D3 is cut off, and the non-inverting input terminal of the operational amplifier U2B is a high level, which is greater than the second reference voltage Vref2. Therefore, U2B outputs a high level, the transistor Q1 is turned on, the relay K1 is energized and closed, and the terminal block J1 outputs an alarm signal;

[0038] Taking into account the fluctuation interference problem between the error amplification voltage and the critical value of the comparison reference voltage, a delay circuit is added to the circuit to effectively avoid such problems. The delay time can be adjusted by changing the device parameters.

[0039] The circuit provided in this embodiment can be applied to circuit breakers of various specifications. The rated currents of the circuit breakers are different, and the temperatures when overloaded are slightly different. Different comparison reference voltages can be obtained by adjusting the adjustable potentiometer R9, and can be applied to products of various specifications.

[0040] The circuit provided in this embodiment does not need to be provided with a diode D2 when applied to single-channel temperature collection and monitoring; the first reference voltage circuit can adopt a simple two-resistance voltage divider circuit;

[0041] The circuit provided in this embodiment can also be applied to multi-channel temperature collection and monitoring, in which case a diode D2 is required; then Figure 1 The circuit on the left side of the middle diode D2 can be simply repeated multiple times. Once the temperature of a circuit of the circuit breaker reaches the overload temperature first, the product can send out an overload alarm signal.

[0042] The mechanical structure of the circuit breaker is designed to trip in the event of a short circuit and not trip in the event of an overload; the focus of this application is on introducing the circuit, so the introduction to the mechanical structure of the circuit breaker is omitted.

[0043] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A temperature-controlled molded case circuit breaker overload alarm non-tripping device, characterized in that: The device comprises a current output terminal (1), a static iron core (2) and a thermal element (5) are mounted on the current output terminal (1), a thermally conductive insulating member is mounted on the thermal element (5), a thermistor (9) is mounted in the thermally conductive insulating member, the thermistor (9) is connected to a signal line (11), the signal line (11) is connected to a controller (12), the thermal element (5) is connected to a flexible connection (10), and the controller (12) is mounted on a circuit breaker housing; the thermally conductive insulating member is a ceramic member; the ceramic member comprises a first ceramic sheet (7) and The first ceramic sheet (7) and the second ceramic sheet (8) are both of a half-cavity structure, the thermal element (5) is connected to the first ceramic sheet (7) and the second ceramic sheet (8) by screws (6), the thermistor (9) is arranged in the cavity of the first ceramic sheet (7) and the second ceramic sheet (8), the first ceramic sheet (7) and the second ceramic sheet (8) have an outlet on the side, one end of the signal line (11) is connected to the thermistor (9), and the other end passes through the outlet to be connected to the controller (12).

2. The temperature-controlled molded case circuit breaker overload alarm non-tripping device according to claim 1, characterized in that: The current output terminal (1) and the static iron core (2) are riveted and fixed by a first rivet (3).

3. The temperature-controlled molded case circuit breaker overload alarm non-tripping device according to claim 1, characterized in that: The current output terminal (1) and the thermal element (5) are riveted and fixed by a second rivet (4).

4. The temperature-controlled molded case circuit breaker overload alarm non-tripping device according to claim 1, characterized in that: The thermal element (5) is connected to the flexible connection (10) by welding.

5. The temperature-controlled molded case circuit breaker overload alarm non-tripping device according to claim 1, characterized in that: The flexible connection (10) is made of copper.

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