阅读说明：本技术 一种继电器 (Relay ) 是由 蒋千枝 吴凯 叶利锋 于 2019-03-28 设计创作，主要内容包括：本发明公开一种继电器。继电器包括：第一过流检测电路、第二过流检测电路、过流检测切换电路、延时电路、过流信号处理电路、过流指示电路和保护动作信号输出电路。当第一过流检测电路检测到回路中存在过流信号时,过流指示电路会发出第一过流指示信号。经过延时电路设定的延时时间后,若第二过流检测电路仍然能够检测到过流信号,则发出第二过流指示信号,同时,保护动作信号输出电路将会输出保护动作触发信号给后端报警动作设备。可见,本发明提供的继电器,不仅能够分别检测瞬间过电流和持续过电流的情况,而且能够有效规避过电流消失而导致的误动作,解决了被测回路中存在毫秒级过电流或浪涌导致继电器误动作的问题。(The invention discloses a relay. The relay includes: the overcurrent protection circuit comprises a first overcurrent detection circuit, a second overcurrent detection circuit, an overcurrent detection switching circuit, a delay circuit, an overcurrent signal processing circuit, an overcurrent indicating circuit and a protection action signal output circuit. When the first overcurrent detection circuit detects that an overcurrent signal exists in the loop, the overcurrent indicating circuit can send out a first overcurrent indicating signal. After the delay time set by the delay circuit, if the second overcurrent detection circuit can still detect the overcurrent signal, a second overcurrent indication signal is sent out, and meanwhile, the protection action signal output circuit outputs a protection action trigger signal to the rear-end alarm action equipment. Therefore, the relay provided by the invention not only can respectively detect the conditions of instantaneous overcurrent and continuous overcurrent, but also can effectively avoid misoperation caused by the disappearance of the overcurrent, and solves the problem of the misoperation of the relay caused by millisecond-level overcurrent or surge in a detected loop.)

1. A relay, characterized in that the relay comprises: the overcurrent protection circuit comprises a first overcurrent detection circuit, a second overcurrent detection circuit, an overcurrent detection switching circuit, a delay circuit, an overcurrent signal processing circuit, an overcurrent indicating circuit and a protection action signal output circuit; wherein the content of the first and second substances,

the input end of the first overcurrent detection circuit is connected with a circuit to be detected, and the output end of the first overcurrent detection circuit is connected with the first input end of the overcurrent indicating circuit; when the first overcurrent detection circuit detects an overcurrent signal, the overcurrent indicating circuit sends a first overcurrent indicating signal;

the input end of the delay circuit is connected with the output end of the first overcurrent detection circuit, the output end of the delay circuit is connected with the control end of the overcurrent detection switching circuit, the input end of the overcurrent detection switching circuit is connected with the circuit to be detected, and the output end of the overcurrent detection switching circuit is connected with the input end of the second overcurrent detection circuit; the over-current detection switching circuit controls the on-off of the circuit to be detected and the second over-current detection circuit according to a control signal of a control end;

the output end of the over-current signal processing circuit is connected with the second input end of the over-current indicating circuit and the control end of the protection action signal output circuit respectively; when the first overcurrent detection circuit and the second overcurrent detection circuit both detect overcurrent signals, the overcurrent indicating circuit sends out second overcurrent indicating signals, and the protection action signal output circuit outputs protection action trigger signals.

2. The relay according to claim 1, wherein said first overcurrent detection circuit comprises: the leakage protection circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first diode, a second diode, a first capacitor, a second capacitor, an M54123 leakage protection control chip, a fifth resistor, a sixth resistor, a third capacitor, a fourth capacitor and a fifth capacitor; wherein the content of the first and second substances,

the first end of the first resistor is respectively connected with the first output end of the circuit to be tested, the first end of the third resistor, the first end of the first diode, the first end of the second diode, the first end of the first capacitor and the pin 1 of the M54123 leakage protection control chip;

the second end of the first resistor is connected with the first end of the second resistor and the first end of the fifth resistor respectively, the second end of the second resistor is connected with the second output end of the circuit to be tested through a normally closed contact in the over-current detection switching circuit, the second end of the fifth resistor is connected with the second end of the third resistor and the first end of the fourth resistor respectively, the second end of the fourth resistor is connected with the second end of the first diode, the second end of the second diode and the first end of the second capacitor respectively, and the second end of the first capacitor and the second end of the second capacitor are both grounded;

the 2 pin of the M54123 electric leakage protection control chip is connected with the first end of the second capacitor, the 3 pin of the M54123 electric leakage protection control chip is grounded, the 4 pin and the 5 pin of the M54123 electric leakage protection control chip are both connected with the first end of the third capacitor, the second end of the third capacitor is grounded, the 6 pin of the M54123 electric leakage protection control chip is connected with the first end of the fourth capacitor, the second end of the fourth capacitor is grounded, the 7 pin of the M54123 electric leakage protection control chip is the output end of the first overcurrent detection circuit, the 8 pin of the M54123 electric leakage protection control chip is respectively connected with the first end of the sixth resistor and the first end of the fifth capacitor, the second end of the sixth resistor is connected with a 12V direct current power supply, and the second end of the fifth capacitor is grounded.

3. The relay according to claim 2, wherein said overcurrent detection switching circuit comprises: a switching relay and a switching triode; wherein the content of the first and second substances,

the control end of the coil of the switching relay is connected with the collector of the switching triode, the common contact of the switching relay is connected with the second output end of the circuit to be detected, the normally closed contact of the switching relay is connected with the second end of the second resistor, the normally open contact of the switching relay is connected with the input end of the second overcurrent detection circuit, the base of the switching triode is connected with the output end of the delay circuit, and the emitter of the switching triode is grounded.

4. A relay according to claim 3, characterized in that the switching relay is an HRS1H-S DC5V relay.

5. The relay according to claim 1, wherein said over-current signal processing circuit comprises an and-gate chip, an output terminal of said first over-current detection circuit is connected to a first input terminal of said and-gate chip, an output terminal of said second over-current detection circuit is connected to a second input terminal of said and-gate chip, and an output terminal of said and-gate chip is an output terminal of said over-current signal processing circuit.

6. The relay according to claim 5, wherein said AND gate chip is a 74LS08 chip.

7. The relay according to claim 1, wherein said overcurrent indicating circuit comprises: the device comprises a red-yellow double-color common anode diode, a yellow indicating resistor, a red indicating resistor, an indicating triode, an indicating resistor and a single-phase silicon controlled rectifier chip; wherein the content of the first and second substances,

the first end of the indicating resistor is connected with the output end of the first overcurrent detection circuit, the second end of the indicating resistor is connected with the base electrode of the indicating triode, the emitting electrode of the indicating triode is grounded, the collecting electrode of the indicating triode is connected with the cathode of the yellow side of the red-yellow double-color common anode diode through a yellow indicating resistor, and the common anode of the red-yellow double-color common anode diode is connected with an indicating direct-current power supply;

the cathode of the red side of the red-yellow double-color common anode diode is connected with one end of a red indicating resistor, the other end of the red indicating resistor is connected with the input end of the single-phase silicon controlled chip, the output end of the single-phase silicon controlled chip is grounded, and the control end of the single-phase silicon controlled chip is connected with the output end of the overcurrent signal processing circuit.

8. The relay according to claim 1, wherein said protection action signal output circuit comprises a relay.

Technical Field

The invention relates to the field of electrical equipment, in particular to a relay.

Background

The existing relay is locked immediately once detecting an overcurrent signal, and outputs an alarm and a contact action signal. When mS level overcurrent or surge exists in a tested loop, the relay sends out a protection action signal, so that the probability of misoperation of the relay is greatly increased.

Disclosure of Invention

The invention aims to provide a relay, which not only can detect the conditions of instantaneous overcurrent and continuous overcurrent respectively, but also can effectively avoid misoperation caused by the disappearance of the overcurrent, and solve the problem of the misoperation of the relay caused by millisecond-level overcurrent or surge existing in a tested loop.

In order to achieve the purpose, the invention provides the following scheme:

a relay, the relay comprising: the overcurrent protection circuit comprises a first overcurrent detection circuit, a second overcurrent detection circuit, an overcurrent detection switching circuit, a delay circuit, an overcurrent signal processing circuit, an overcurrent indicating circuit and a protection action signal output circuit; wherein the content of the first and second substances,

the input end of the first overcurrent detection circuit is connected with a circuit to be detected, and the output end of the first overcurrent detection circuit is connected with the first input end of the overcurrent indicating circuit; when the first overcurrent detection circuit detects an overcurrent signal, the overcurrent indicating circuit sends a first overcurrent indicating signal;

the input end of the delay circuit is connected with the output end of the first overcurrent detection circuit, the output end of the delay circuit is connected with the control end of the overcurrent detection switching circuit, the input end of the overcurrent detection switching circuit is connected with the circuit to be detected, and the output end of the overcurrent detection switching circuit is connected with the input end of the second overcurrent detection circuit; the over-current detection switching circuit controls the on-off of the circuit to be detected and the second over-current detection circuit according to a control signal of a control end;

the output end of the over-current signal processing circuit is connected with the second input end of the over-current indicating circuit and the control end of the protection action signal output circuit respectively; when the first overcurrent detection circuit and the second overcurrent detection circuit both detect overcurrent signals, the overcurrent indicating circuit sends out second overcurrent indicating signals, and the protection action signal output circuit outputs protection action trigger signals.

Optionally, the first over-current detection circuit includes: the leakage protection circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first diode, a second diode, a first capacitor, a second capacitor, an M54123 leakage protection control chip, a fifth resistor, a sixth resistor, a third capacitor, a fourth capacitor and a fifth capacitor; wherein the content of the first and second substances,

the first end of the first resistor is respectively connected with the first output end of the circuit to be tested, the first end of the third resistor, the first end of the first diode, the first end of the second diode, the first end of the first capacitor and the pin 1 of the M54123 leakage protection control chip;

the second end of the first resistor is connected with the first end of the second resistor and the first end of the fifth resistor respectively, the second end of the second resistor is connected with the second output end of the circuit to be tested through a normally closed contact in the over-current detection switching circuit, the second end of the fifth resistor is connected with the second end of the third resistor and the first end of the fourth resistor respectively, the second end of the fourth resistor is connected with the second end of the first diode, the second end of the second diode and the first end of the second capacitor respectively, and the second end of the first capacitor and the second end of the second capacitor are both grounded;

the 2 pin of the M54123 electric leakage protection control chip is connected with the first end of the second capacitor, the 3 pin of the M54123 electric leakage protection control chip is grounded, the 4 pin and the 5 pin of the M54123 electric leakage protection control chip are both connected with the first end of the third capacitor, the second end of the third capacitor is grounded, the 6 pin of the M54123 electric leakage protection control chip is connected with the first end of the fourth capacitor, the second end of the fourth capacitor is grounded, the 7 pin of the M54123 electric leakage protection control chip is the output end of the first overcurrent detection circuit, the 8 pin of the M54123 electric leakage protection control chip is respectively connected with the first end of the sixth resistor and the first end of the fifth capacitor, the second end of the sixth resistor is connected with a 12V direct current power supply, and the second end of the fifth capacitor is grounded.

Optionally, the over-current detection switching circuit includes: a switching relay and a switching triode; wherein the content of the first and second substances,

the control end of the coil of the switching relay is connected with the collector of the switching triode, the common contact of the switching relay is connected with the second output end of the circuit to be detected, the normally closed contact of the switching relay is connected with the second end of the second resistor, the normally open contact of the switching relay is connected with the input end of the second overcurrent detection circuit, the base of the switching triode is connected with the output end of the delay circuit, and the emitter of the switching triode is grounded.

Optionally, the switching relay is an HRS1H-S DC5V relay.

Optionally, the over-current signal processing circuit includes an and gate chip, an output end of the first over-current detection circuit is connected to a first input end of the and gate chip, an output end of the second over-current detection circuit is connected to a second input end of the and gate chip, and an output end of the and gate chip is an output end of the over-current signal processing circuit.

Optionally, the and gate chip is a 74LS08 chip.

Optionally, the over-current indication circuit includes: the device comprises a red-yellow double-color common anode diode, a yellow indicating resistor, a red indicating resistor, an indicating triode, an indicating resistor and a single-phase silicon controlled rectifier chip; wherein the content of the first and second substances,

the first end of the indicating resistor is connected with the output end of the first overcurrent detection circuit, the second end of the indicating resistor is connected with the base electrode of the indicating triode, the emitting electrode of the indicating triode is grounded, the collecting electrode of the indicating triode is connected with the cathode of the yellow side of the red-yellow double-color common anode diode through a yellow indicating resistor, and the common anode of the red-yellow double-color common anode diode is connected with an indicating direct-current power supply;

the cathode of the red side of the red-yellow double-color common anode diode is connected with one end of a red indicating resistor, the other end of the red indicating resistor is connected with the input end of the single-phase silicon controlled chip, the output end of the single-phase silicon controlled chip is grounded, and the control end of the single-phase silicon controlled chip is connected with the output end of the overcurrent signal processing circuit.

Optionally, the protection action signal output circuit includes a relay.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the relay provided by the invention comprises: the overcurrent protection circuit comprises a first overcurrent detection circuit, a second overcurrent detection circuit, an overcurrent detection switching circuit, a delay circuit, an overcurrent signal processing circuit, an overcurrent indicating circuit and a protection action signal output circuit. When the first overcurrent detection circuit detects that an overcurrent signal exists in the loop, the overcurrent indicating circuit can send out a first overcurrent indicating signal. After the delay time set by the delay circuit, if the second overcurrent detection circuit can still detect the overcurrent signal, a second overcurrent indication signal is sent out, and meanwhile, the protection action signal output circuit outputs a protection action trigger signal to the rear-end alarm action equipment. Therefore, the relay provided by the invention not only can respectively detect the conditions of instantaneous overcurrent and continuous overcurrent, but also can effectively avoid misoperation caused by the disappearance of the overcurrent, and solves the problem of the misoperation of the relay caused by millisecond-level overcurrent or surge in a detected loop.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a block diagram of a relay according to an embodiment of the present invention;

fig. 2 is a circuit diagram of a first over-current detection circuit according to an embodiment of the present invention;

fig. 3 is a circuit diagram of a second over-current detection circuit according to an embodiment of the present invention;

fig. 4 is a circuit diagram of an over-current detection switching circuit according to an embodiment of the present invention;

fig. 5 is a circuit diagram of an over-current signal processing circuit according to an embodiment of the present invention;

fig. 6 is a circuit diagram of an overcurrent indicating circuit, a protection operation signal output circuit, and a reset circuit according to an embodiment of the present invention;

fig. 7 is an overcurrent operation current value adjusting circuit of the first overcurrent detecting circuit according to the embodiment of the present invention;

fig. 8 is an overcurrent operation current value adjusting circuit of the second overcurrent detecting circuit according to the embodiment of the present invention;

fig. 9 is a relay test/reset keying circuit provided in accordance with an embodiment of the present invention;

fig. 10 is a mechanical outline view of a relay according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a relay, which not only can detect the conditions of instantaneous overcurrent and continuous overcurrent respectively, but also can effectively avoid misoperation caused by the disappearance of the overcurrent, and solve the problem of the misoperation of the relay caused by millisecond-level overcurrent or surge existing in a tested loop.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Fig. 1 is a block diagram of a relay according to an embodiment of the present invention. As shown in fig. 1, a relay includes: the overcurrent protection circuit comprises a first overcurrent detection circuit 1, a second overcurrent detection circuit 2, an overcurrent detection switching circuit 3, a delay circuit 4, an overcurrent signal processing circuit 5, an overcurrent indicating circuit 6 and a protection action signal output circuit 7.

The input end of the first over-current detection circuit 1 is connected with a circuit to be detected, and the output end of the first over-current detection circuit 1 is connected with the first input end of the over-current indication circuit 6; when the first over-current detection circuit 1 detects an over-current signal, the over-current indication circuit 6 sends a first over-current indication signal.

The input end of the delay circuit 4 is connected with the output end of the first over-current detection circuit 1, the output end of the delay circuit 4 is connected with the control end of the over-current detection switching circuit 3, the input end of the over-current detection switching circuit 3 is connected with the circuit to be detected, and the output end of the over-current detection switching circuit 3 is connected with the input end of the second over-current detection circuit 2; the over-current detection switching circuit 3 controls the on-off of the circuit to be detected and the second over-current detection circuit 2 according to a control signal of a control end.

The output end of the first overcurrent detection circuit 1 is connected with the first input end of the overcurrent signal processing circuit 5, the output end of the second overcurrent detection circuit 2 is connected with the second input end of the overcurrent signal processing circuit 5, and the output end of the overcurrent signal processing circuit 5 is respectively connected with the second input end of the overcurrent indicating circuit 6 and the control end of the protection action signal output circuit 7; when the first overcurrent detection circuit 1 and the second overcurrent detection circuit 2 both detect overcurrent signals, the overcurrent indication circuit 6 sends out a second overcurrent indication signal, and the protection action signal output circuit 7 outputs a protection action trigger signal.

Fig. 2 is a circuit diagram of a first over-current detection circuit according to an embodiment of the present invention. As shown in fig. 2, the first overcurrent detecting circuit 1 includes: the leakage protection circuit comprises a first resistor R18-1, a second resistor R19-1, a third resistor R3-1, a fourth resistor R4-1, a first diode D1-1, a second diode D2-1, a first capacitor C1-1, a second capacitor C6-1, an M54123 leakage protection control chip, a fifth resistor R20-1, a sixth resistor R8-1, a third capacitor C2-1, a fourth capacitor C3-1 and a fifth capacitor C5-1.

The first end of the first resistor R18-1 is respectively connected with the first output end of the circuit to be tested, the first end of the third resistor R3-1, the first end of the first diode D1-1, the first end of the second diode D2-1, the first end of the first capacitor C1-1 and the pin 1 of the M54123 leakage protection control chip;

a second end of the first resistor R18-1 is connected to a first end of the second resistor R19-1 and a first end of the fifth resistor R20-1, a second end of the second resistor R19-1 is connected to a second output terminal of the circuit to be tested through a normally closed contact in the over-current detection switching circuit 3, a second end of the fifth resistor R20-1 is connected to a second end of the third resistor R3-1 and a first end of the fourth resistor R4-1, a second end of the fourth resistor R4-1 is connected to a second end of the first diode D1-1, a second end of the second diode D2-1 and a first end of the second capacitor C6-1, and a second end of the first capacitor C1-1 and a second end of the second capacitor C6-1 are both grounded.

The pin 2 of the M54123 leakage protection control chip is connected with the first end of the second capacitor C6-1, the pin 3 of the M54123 leakage protection control chip is grounded, the pins 4 and 5 of the M54123 leakage protection control chip are both connected with the first end of the third capacitor C2-1, the second end of the third capacitor C2-1 is grounded, the pin 6 of the M54123 leakage protection control chip is connected with the first end of the fourth capacitor C3-1, the second end of the fourth capacitor C3-1 is grounded, pin 7 of the M54123 earth leakage protection control chip is the output end of the first over-current detection circuit 1, the 8 pins of the M54123 leakage protection control chip are respectively connected with the first end of the sixth resistor R8-1 and the first end of the fifth capacitor C5-1, the second end of the sixth resistor R8-1 is connected with a 12V direct-current power supply, and the second end of the fifth capacitor C5-1 is grounded. In practical application, JP8 in fig. 2 is connected with the secondary winding of the zero sequence current transformer.

Fig. 3 is a circuit diagram of a second over-current detection circuit according to an embodiment of the present invention. As shown in fig. 3, the circuit structure and the operation principle of the second over current detection circuit 2 in this embodiment are similar to those of the first over current detection circuit 1, and are not described herein again.

Fig. 4 is a circuit diagram of an over-current detection switching circuit according to an embodiment of the present invention. As shown in fig. 4, the overcurrent detection switching circuit 3 includes: switching relays and switching transistor Q3. The control end of the coil of the switching relay is connected with the collector of the switching triode Q3, the common contact of the switching relay is connected with the second output end of the circuit to be tested, the normally closed contact of the switching relay is connected with the second end of the second resistor R19-1, the normally open contact of the switching relay is connected with the input end of the second overcurrent detection circuit 2, the base of the switching triode Q3 is connected with the output end of the delay circuit 4, and the emitter of the switching triode Q3 is grounded. In the embodiment, the switching relay is an HRS1H-S DC5V relay.

Fig. 5 is a circuit diagram of an over-current signal processing circuit according to an embodiment of the present invention. As shown in fig. 5, the over-current signal processing circuit 5 includes an and-gate chip, an output end of the first over-current detection circuit 1 is connected to a first input end of the and-gate chip, an output end of the second over-current detection circuit 2 is connected to a second input end of the and-gate chip, and an output end of the and-gate chip is an output end of the over-current signal processing circuit 5. In this embodiment, the and gate chip is a 74LS08 chip.

Fig. 6 is a circuit diagram of an overcurrent indicating circuit, a protection operation signal output circuit, and a reset circuit according to an embodiment of the present invention. As shown in fig. 6, the overcurrent indicating circuit 6 includes: the LED comprises a red-yellow double-color common anode diode LED1, a yellow indicating resistor R15, a red indicating resistor R6, an indicating triode Q2, an indicating resistor R2 and a single-phase silicon controlled chip Q1; wherein the content of the first and second substances,

the first end of the indicating resistor R2 is connected with the output end of the first overcurrent detection circuit 1, the second end of the indicating resistor R2 is connected with the base electrode of the indicating triode Q2, the emitting electrode of the indicating triode Q2 is grounded, the collecting electrode of the indicating triode Q2 is connected with the cathode Y of the yellow side of the red-yellow double-color common anode diode through a yellow indicating resistor R15, and the common anode of the red-yellow double-color common anode diode is connected with an indicating direct-current power supply. The cathode R at the red side of the red-yellow double-color common anode diode is connected with one end of R6 of a red indicating resistor, the other end of the red indicating resistor R6 is connected with the input end of the single-phase silicon controlled chip Q1, the output end of the single-phase silicon controlled chip Q1 is grounded, and the control end of the single-phase silicon controlled chip Q1 is connected with the output end of the overcurrent signal processing circuit 5. In this embodiment, the dc power supply is indicated to be a 25V dc power supply.

As shown in fig. 6, the protection operation signal output circuit 7 in the present embodiment includes a relay JD1, model G2R-2.

When the first overcurrent detection circuit 1 has a locking action signal to be transmitted to the pin 9 of the 74LS08, whether the second overcurrent detection circuit 2 after waiting for delay has the locking action signal to be transmitted to the pin 10 of the 74LS08 or not is judged, if yes, the pin 8 of the 74LS08 outputs high level to control the single-phase silicon controlled chip Q1 to drive the G2R-2 relay to act according to the operation logic of the AND gate, the normally open contact is closed, the normally closed contact is opened, and an alarm signal is output. If not, according to the operational logic 8 pin of the AND gate, no high level is output, the G2R-2 relay does not act, the normally open contact and the normally closed contact are not turned over, and no alarm signal is output.

In this embodiment, the relay further includes a 5V single live wire power supply circuit. The 5V single-live-wire power circuit comprises a rectifier bridge module DP2W100 and a power module PI-05V-B4, wherein pins 2 and 4 of the rectifier bridge module are connected with the output end of a power transformer, and pin 1 is connected with the input end IN of a PI-05V-B4. The output end OUT of the PI-05V-B4 is connected with a pin 5 of the switching relay and a pin 14 of the 74LS08 chip, and is used for supplying +5V voltage to the switching relay, the 74LS08 and the gate.

Fig. 7 is an overcurrent operation current value adjusting circuit of the first overcurrent detecting circuit according to the embodiment of the present invention. Fig. 8 is an overcurrent operation current value adjusting circuit of the second overcurrent detecting circuit according to the embodiment of the present invention. The overcurrent reference value of the first overcurrent detection circuit can be adjusted by the overcurrent operation current value adjustment circuit shown in fig. 7, and the overcurrent reference value of the second overcurrent detection circuit can be adjusted by the overcurrent operation current value adjustment circuit shown in fig. 8.

Fig. 9 is a relay test/reset keying circuit provided by an embodiment of the present invention. The present embodiment is also provided with a relay test key CS and a reset key FW. As can be seen from fig. 5 and 6, when the reset key FW is pressed, the coil of the reset relay FWJD is energized, and the electromagnet is attracted, so that the system power supply module is momentarily short-circuited to reset the electrical logic of the relay.

Fig. 10 is a mechanical outline view of a relay according to an embodiment of the present invention. As shown in parts (a) and (b) of fig. 10, the mechanical structure of the relay provided in the present embodiment includes a housing 61, a main board 62, a connection terminal 63, a name plate 64, and an end cap 65; a transparent cover 66 and a control panel 67. The main board 62 is located inside the housing 61 and connected to the control board 67, the control board 67 is located inside the housing 61 and connected to the connection terminal 663, and the end cap 65 is located on the upper portion of the housing 61 and connected to the connection terminal 63 and the control board 667. The nameplate 64 is located on the end cap 65 and the transparent cover 66 is located on the end cap 65. The first overcurrent detection circuit 1, the second overcurrent detection circuit 2, the overcurrent detection switching circuit 3, the delay circuit 4, the overcurrent signal processing circuit 5, the overcurrent indicating circuit 6, the protection action signal output circuit 7 and other relay forming circuits are all located on the control board 67.

In practical application, the circuit to be tested is supposed to have 0.6 second starting current (instantaneous surge current), and the relay is not allowed to output a red alarm signal and a protection signal. One of R9-R12 in the delay circuit is set to delay 1 second corresponding to the required resistance value, and the gear of the action time is shifted to the corresponding 1 second gear. When starting current comes, the yellow lamp is lighted, and the red lamp is not lighted after 1 second delay, which indicates normal starting current; if the red light is lighted after 1 second of time delay, the protection action signal output relay switches on a subsequent alarm and protection equipment control loop to send out alarm and trip conditions, which indicates the abnormal condition of over-current with the time length longer than 1 second.

The relay provided by the invention optimizes the technical scheme that the existing relay is locked immediately once detecting an overcurrent signal and outputs an alarm and contact action signal into an alarm mechanism with two degree grades, and a yellow alarm lamp is turned on and a contact does not act when a transient light overcurrent occurs. When continuous heavy overcurrent occurs, the red alarm lamp is turned on and outputs a contact action signal, so that the problem of relay misoperation caused by ms-level overcurrent or surge in a tested loop is successfully solved.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.