Safe and efficient elevator electrical safety device grounding detection circuit and device
By designing the ground detection circuit of the elevator electrical safety device, using Hall sensors and single-pole multi-throw switches to detect the grounding of the electrical device, the problems of low efficiency and insufficient safety in the prior art are solved, and more efficient and safer ground detection is achieved.
Patent Information
- Application Number
- CN202422055183.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-22
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-08-22
AI Technical Summary
The ground detection method of existing elevator electrical safety devices is inefficient and insufficient in safety, which can easily lead to equipment damage and leakage protector operation.
An elevator electrical safety device ground detection circuit including a ground signal acquisition circuit, a first electronically controlled switch, a signal processing circuit, a second electronically controlled switch and an indication circuit is designed. The grounding condition of the electrical device is detected by using a Hall sensor and a single-pole multi-throw switch, and a clear detection result is provided through the indication circuit.
It realizes safer and more efficient grounding detection, and can determine whether the electrical device housing is successfully grounded in a short time, improving the reliability and efficiency of detection.
Smart Images
Figure CN223244788U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of detection equipment for electrical equipment, in particular to a safe and efficient grounding detection circuit and device for an elevator electrical safety device. Background Art
[0002] In various electrical equipment, some equipment not only needs to have its ground wire successfully grounded, but also its shell needs to be successfully grounded to prevent the occurrence of safety accidents that affect normal life and production. Taking the elevator as an example, the electrical safety devices in different spaces in the elevator (such as the electrical contacts of the door locks) are connected in series to form a safety chain, such as Figure 3 From fuse F to the coil of safety relay J At the end, if any electrical safety device is disconnected, the safety relay will lose power and the elevator will not be able to run. These switches in the elevator equipment, which are usually connected in series, are defined as electrical safety devices. They mainly serve as interlocking protection. For example, the elevator cannot run when the door of a certain floor is not closed, and the overspeed switch is disconnected when the elevator is overspeeding, causing the elevator to stop running. In order to prevent the electrical safety device connected in series between the two short-circuit points from losing its effectiveness when two or more circuits are grounded or contact metal components in the electrical safety circuit, GB / T 7588-2020 "Safety Specifications for Elevator Manufacturing and Installation" has increased the scope of circuits that need to be protected from grounding faults. In this way, it is also necessary to verify that the power supply of the elevator's safety circuit and the brake circuit should not be a suspended isolated power supply and whether the metal parts of the electrical safety device and brake accessories are reliably grounded. Therefore, regardless of the power supply of the electrical safety device No matter how low and safe the voltage is, the non-energized metal casing of each electrical safety device (or the metal component that secures the electrical safety device) must be grounded. This means that each electrical safety device must have a ground wire to reduce the risk of the circuit being bypassed by metal components when multiple points of contact occur. Under normal circumstances, the casing of electrical equipment in the safety chain does not generate ground current. If it is manually touched to the ground, the upper limit of the ground current is very large, which does not comply with safety testing regulations. On April 1, 2016, the Guangdong Provincial Quality Supervision Bureau issued a "Notice on the Investigation of Potential Safety Risks of Electrical Circuit Grounding Protection in Elevators Manufactured by Shanghai Zhongxun Sailerwa Elevator Factory Co., Ltd." The document provided a reference method: a. Disconnect the main power switch; b. Manually ground the aforementioned safety device or door lock; c. Close the main power switch; d. Observe whether the short-circuit protection device in the circuit is activated; e. If the short-circuit protection device does not activate, it can be determined that the elevator's electrical circuit short-circuit protection is not providing protection. This method is not only extremely inefficient, but also has low safety because of the huge ground current generated, which can easily cause equipment damage: it can damage components such as the Darlington power driver IC chip and rectifier bridge with a maximum current allowable value of 4A, and may even cause the leakage protector in the power supply system to operate and cause a power outage.
[0003] In view of this, a simpler and safer detection circuit or device is needed that can quickly verify whether the non-charged metal casing in the electrical safety device is successfully grounded and whether the circuit power supply of the electrical safety device is not a floating isolated power supply. Utility Model Content
[0004] In response to the shortcomings of the existing technology, the utility model provides a safe and efficient elevator electrical safety device grounding detection circuit and device. By designing a new grounding detection circuit, it solves the problems of excessive leakage current, low safety and efficiency, and long test time during grounding safety testing.
[0005] The utility model discloses a safe and efficient grounding detection circuit for an elevator electrical safety device through an embodiment, comprising a grounding signal acquisition circuit, a first electric control switch, a power supply, a signal processing circuit, a second electric control switch and an indication circuit; the output end of the grounding signal acquisition circuit is connected to the input end of the signal processing circuit; the output end of the signal processing circuit is connected to the control end of the second electric control switch; the second electric control switch is used to control the on / off of the control circuit and the indication circuit of the first electric control switch; the first electric control switch is used to control the on / off of the grounding signal acquisition circuit; the power supply is used to supply power to the first electric control switch, the signal processing circuit, the second electric control switch and the indication circuit; and the indication circuit uses a pointer-type visual signal and an auditory sound signal in combination to indicate the detection result of the grounding detection.
[0006] Furthermore, the ground signal acquisition circuit includes a DC acquisition branch, an AC acquisition branch and a single-pole multi-throw switch.
[0007] Furthermore, the DC acquisition branch includes a Hall sensor circuit, a first DC wiring branch, and a second DC wiring branch; the Hall sensor circuit includes a Hall sensor fixed to the transformer core, a 0.7V precision servo power supply for the Hall sensor, a Hall current amplifier, a transformer, a first primary coil, and a secondary coil; the first end of the first primary coil is connected to the first DC wiring branch, and the second end of the first primary coil is connected to the second DC wiring branch via a first electronically controlled switch and a single-pole multi-throw switch, wherein the first electronically controlled switch is connected to the fixed terminal of the single-pole multi-throw switch, and the second DC wiring branch is connected to the first movable terminal of the single-pole multi-throw switch; a plurality of resistors are provided on both the first DC wiring branch and the second DC wiring branch to reduce the current passing through the first primary coil; and the two ends of the secondary coil serve as the output ends of the ground signal acquisition circuit. It is worth noting that in actual applications, an inductor can be connected to the first DC wiring branch or the second DC wiring branch to store DC grounding energy, thereby preventing the current in the circuit from disappearing immediately, thereby improving the reliability of DC grounding current detection.
[0008] Furthermore, the AC acquisition branch includes a Hall sensor circuit, a first AC wiring branch, a second AC wiring branch, and a third AC wiring branch; the Hall sensor circuit includes a Hall sensor fixed to the transformer core, a 0.7V precision servo power supply for the Hall sensor, a Hall current amplifier, a transformer, a second primary coil, and a secondary coil; the first end of the second primary coil is connected to the first AC wiring branch via a first electrically controlled switch and a single-pole multi-throw switch, the first end of the second primary coil is connected to the second AC wiring branch via the first electrically controlled switch and the single-pole multi-throw switch, and the second end of the second primary coil is connected to the third AC wiring branch, wherein the first electrically controlled switch is connected to the fixed terminal of the single-pole multi-throw switch, the first AC wiring branch is connected to the second movable terminal of the single-pole multi-throw switch, and the second AC wiring branch is connected to the third movable terminal of the single-pole multi-throw switch; a plurality of resistors are provided on both the second AC wiring branch and the third AC wiring branch to reduce the current passing through the second primary coil and improve the circuit's voltage withstand capability (the voltage withstand value of a single chip resistor may be difficult to reach several hundred volts); and the two ends of the secondary coil serve as output terminals of the ground signal acquisition circuit. It is worth noting that there are a first AC wiring branch, a second AC wiring branch and a third AC wiring branch here, wherein the first AC wiring branch and the second AC wiring branch are used to connect the positive pole of AC power of different voltages, and the third AC wiring branch is used for the negative pole circuit.
[0009] Furthermore, the signal processing circuit includes a reference circuit, a thirteenth resistor, a differential amplifier and a signal latch circuit; the output end of the reference circuit is connected to the positive input end of the differential amplifier through the thirteenth resistor; one end of the secondary coil is connected to the reverse input end of the differential amplifier, and the other end is connected to the output end of the reference circuit; the output end of the differential amplifier is connected to the input end of the signal latch circuit; and the output end of the signal latch circuit is connected to the control end of the second electronically controlled switch.
[0010] Furthermore, a potentiometer is connected between the two ends of the secondary coil. One end of the secondary coil is connected to the first fixed terminal and the sliding terminal of the potentiometer, respectively, and the other end is connected to the second fixed terminal of the potentiometer. The potentiometer can be used to adjust the sensitivity of the current sensor in the ground signal acquisition circuit.
[0011] Furthermore, the second electronically controlled switch includes a unidirectional thyristor (SCR), and the output of the signal processing circuit is connected to the control electrode of the SCR. The SCR is used to control the current of the first electronically controlled switch and to indicate whether the current of the circuit is successfully grounded. This further controls the operating status of the first electronically controlled switch and the indication circuit.
[0012] Furthermore, the first electronically controlled switch includes a relay, one end of the input circuit of the relay is connected to the power supply, and the other end is controlled by the second electronically controlled switch to be grounded; the output circuit of the relay is connected to the ground signal acquisition circuit using a normally closed connection method, and is used to control the on and off of the ground signal acquisition circuit.
[0013] Furthermore, the indicating circuit includes a galvanometer and a buzzer; one end of the galvanometer and the buzzer is connected to the power supply, and the other end of the galvanometer and the buzzer is controlled by a second electronically controlled switch to be grounded.
[0014] Of course, in actual operation, a power indicator can also be added to the power supply to indicate the power supply status and whether it is connected to the detection circuit. For example, a light-emitting diode can be connected to the positive terminal of the power supply and grounded to indicate that the power supply is successfully outputting current. Furthermore, a main switch can be added to the positive output of the power supply to control whether the battery outputs current to the power indicator, signal processing circuit, first electronically controlled switch, second electronically controlled switch, and indication circuit described above.
[0015] In order to achieve the above-mentioned purpose, the utility model also provides a safe and efficient elevator electrical safety device grounding detection device, which includes the above-mentioned grounding detection circuit for detecting whether the electrical device is grounded.
[0016] It is worth noting that, in the above single-pole multi-throw switch, when the fixed terminal of the single-pole multi-throw switch is connected to its first movable terminal, the ground detection circuit is used to detect the grounding condition of the electrical device casing of the DC equipment; when the fixed terminal of the single-pole multi-throw switch is connected to its first movable terminal or second movable terminal, it is used to detect whether the casing of the electrical device of the AC elevator is successfully grounded.
[0017] The technical principle of the present invention is as follows: the following describes an example in which a fixed terminal of a single-pole multi-throw switch is connected to its first movable terminal to detect the grounding condition of an electrical device housing of a DC device. The first DC wiring branch is connected to the metal casing of the electrical device, and the second DC wiring branch is connected to the DC power supply of the electrical equipment. The power switch of the device is turned on. If the metal casing of the electrical device is not grounded, no current will flow through the Hall circuit and the entire ground detection device will not operate. If the metal casing of the electrical device is successfully grounded, current will flow through the Hall circuit. At this time, the Hall circuit current is output to the output end of the reference circuit and the inverting input end of the differential amplifier. After operation by the differential amplifier, it is output to the signal latch circuit. The signal latch circuit locks the signal and outputs it to control the conduction of the one-way thyristor. At this time, the relay, galvanometer and buzzer are energized and successfully grounded. The normally closed relay is further disconnected, the second DC wiring branch is disconnected from the second end of the first primary coil, and the ground signal acquisition circuit is disconnected, and the ground signal acquisition activity ends. At the same time, the galvanometer and buzzer operate, the galvanometer indicates the current flowing through the galvanometer, and the buzzer sounds, indicating that the metal casing of the electrical safety device and the non-powered end of the power supply are successfully grounded.
[0018] Compared with the prior art, the present invention has the following beneficial effects: safer test action, more direct and clear test results, and the ability to determine whether the housing of the electrical device is successfully grounded in a shorter time, i.e., higher test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solution of the present invention and facilitate a further understanding of the technical effects, technical features and purposes of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation to the present invention.
[0020] Figure 1 This is a schematic diagram of the ground detection circuit described in this utility model;
[0021] Figure 2 Schematic diagram of a ground detection circuit in an embodiment of the present utility model;
[0022] Figure 3 This is a grounding diagram of the electrical safety device mentioned in the background technology of this utility model. DETAILED DESCRIPTION
[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described below are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Furthermore, the portions described in the embodiments or drawings are merely illustrative of the relevant portions of the present invention and are not intended to be exhaustive. All other embodiments derived by those of ordinary skill in the art based on the embodiments of the present invention are intended to fall within the scope of protection of the present invention.
[0024] like Figure 1 As shown, a safe and efficient elevator electrical safety device grounding detection circuit includes a grounding signal acquisition circuit, a first electric control switch KA, a power supply, a signal processing circuit, a second electric control switch SCR and an indication circuit; the output end of the grounding signal acquisition circuit is connected to the input end of the signal processing circuit; the output end of the signal processing circuit is connected to the control end of the second electric control switch SCR; the second electric control switch is used to control the on and off of the control circuit and the indication circuit of the first electric control switch KA; the first electric control switch KA is used to control the on and off of the grounding signal acquisition circuit; the power supply is used to supply power to the first electric control switch KA, the signal processing circuit, the second electric control switch SCR and the indication circuit; and the indication circuit is used to indicate the detection result of the grounding detection.
[0025] like Figure 2As shown, in this embodiment, the ground signal acquisition circuit includes a DC acquisition branch, an AC acquisition branch and a single-pole triple-throw switch SK.
[0026] like Figure 2 As shown, in this embodiment, the DC acquisition branch includes a Hall sensor circuit HL, a first DC wiring branch DCA, and a second DC wiring branch DCB; the Hall sensor circuit HL includes an iron core, a first primary coil Y1, and a secondary coil F; a first end of the first primary coil Y1 is connected to the first DC wiring branch DCA, and a second end of the first primary coil Y1 is connected to the second DC wiring branch DCB via a first electrically controlled switch KA and a single-pole multi-throw switch SK in sequence, wherein the first electrically controlled switch KA is connected to the fixed terminal of the single-pole multi-throw switch SK, and the second DC wiring branch DCB is connected to the first movable terminal of the single-pole multi-throw switch SK; Figure 2 As shown, resistors R1 and R2 are installed on the first DC wiring branch DCA, and resistor R3 is installed on the second DC wiring branch DCB. These resistors are used to reduce the current passing through the first primary coil Y1. The two ends of the secondary coil F serve as the output terminals of the ground signal acquisition circuit. Furthermore, an inductor L is connected to the first DC wiring branch DCA to store DC ground current energy, preventing the current in the circuit from dissipating immediately, thereby improving the reliability of DC ground current detection.
[0027] like Figure 2 As shown, in this embodiment, the AC acquisition branch includes a Hall sensor circuit HL, an AC first wiring branch ACA1, an AC second wiring branch ACA2, and an AC third wiring branch ACB; the Hall sensor circuit HL includes an iron core, a second primary coil Y2, and a secondary coil F; the first end of the second primary coil Y2 is connected to the AC first wiring branch ACA1 through the first electronically controlled switch KA and the single-pole multi-throw switch SK in sequence, the first end of the second primary coil Y2 is connected to the AC second wiring branch ACA2 through the first electronically controlled switch KA and the single-pole multi-throw switch SK in sequence, and the second end of the second primary coil Y2 is connected to the AC third wiring branch ACB, wherein the first electronically controlled switch KA is connected to the fixed terminal of the single-pole multi-throw switch SA, the AC first wiring branch ACA1 is connected to the second moving terminal of the single-pole multi-throw switch SK, and the AC second wiring branch ACA2 is connected to the third moving terminal of the single-pole multi-throw switch SK; as shown Figure 2As shown, resistors R4, R5, and R6 are provided on the second AC wiring branch ACA2, and resistors R7, R8, and R9 are provided on the third AC wiring branch ACB. These resistors are used to reduce the current passing through the second primary coil Y2. The two ends of the secondary coil F serve as the output terminals of the ground signal acquisition circuit. It is worth noting that the first AC wiring branch ACA1, the second AC wiring branch ACA2, and the third AC wiring branch ACB are provided here. The first AC wiring branch ACA1 and the second AC wiring branch ACA2 are used to connect the live electrodes of electrical safety devices with different supply voltages, while the third AC wiring branch ACB is used for the metal casing (or metal component) of the electrical safety device.
[0028] like Figure 2 As shown, in this embodiment, the signal processing circuit includes a reference circuit, a thirteenth resistor R13, a differential amplifier and a signal latch circuit; the output end of the reference circuit is connected to the positive input end of the differential amplifier through the thirteenth resistor R13; one end of the secondary coil is connected to the negative input end of the differential amplifier, and the other end is connected to the output end of the reference circuit; the output end of the differential amplifier is connected to the input end of the signal latch circuit; and the output end of the signal latch circuit is connected to the control end of the second electronically controlled switch SCR.
[0029] like Figure 2 As shown, in this embodiment, a potentiometer W1 is connected between the two ends of the secondary coil F. One end of the secondary coil F is connected to the first fixed terminal and the sliding terminal of the potentiometer W1, respectively, and the other end is connected to the second fixed terminal of the potentiometer W2. The potentiometer can be used to adjust the sensitivity of the Hall sensor circuit HL in the ground signal acquisition circuit.
[0030] like Figure 2 As shown, in this embodiment, the second electronically controlled switch SCR comprises a unidirectional thyristor (SCR). The output of the signal processing circuit is connected to the control electrode of the unidirectional thyristor. The unidirectional thyristor is used to control the current of the first electronically controlled switch KA and to indicate whether the current of the circuit is successfully grounded. Furthermore, the operating status of the first electronically controlled switch KA and the indication circuit can be controlled.
[0031] like Figure 2 As shown, in this embodiment, the first electronically controlled switch KA includes a relay, one end of the input circuit of the relay is connected to the power supply, and the other end is controlled by the second electronically controlled switch SCR to determine whether it is grounded; the output circuit of the relay is connected to the ground signal acquisition circuit using a normally closed connection method, and is used to control the on and off of the ground signal acquisition circuit.
[0032] like Figure 2As shown, in this embodiment, the indicator circuit includes a galvanometer and a buzzer. One end of the galvanometer is connected to the power supply through a resistor R10, and one end of the buzzer is connected to the power supply through a resistor R11. The other ends of the galvanometer and the buzzer are grounded or not, controlled by a second electronically controlled switch SCR.
[0033] Of course, in this embodiment, Figure 2 As shown, a power indicator is also added to the power supply to indicate the status of the power supply: whether it is connected to this detection circuit. The power indicator here is a light-emitting diode connected to the positive pole of the power supply after connecting a resistor R12 that reduces the current. The light-emitting diode is grounded separately to indicate that the power supply is successfully outputting current. At the same time, a main switch PS is added to the positive output of the power supply to control whether the battery outputs current to the power indicator, signal processing circuit, first electronically controlled switch KA, second electronically controlled switch SCR and indication circuit mentioned above. Figure 2 As shown, a freewheeling diode D1 for the KA coil and a diode D2 for preventing current backflow are also provided in the circuit. This belongs to the basic knowledge of the circuit and will not be described in detail in this circuit.
[0034] In order to achieve the above-mentioned purpose, the present invention also provides a safe and efficient elevator electrical safety device grounding detection device, which includes the above-mentioned grounding detection circuit, which is used to detect whether the metal casing of the electrical safety device (or the metal component that fixes the electrical safety device) and the non-powered end of its power supply are grounded.
[0035] It should be noted that the above embodiments are only for more clearly illustrating the technical solutions of the present invention. Those skilled in the art will understand that the implementation methods of the present invention are not limited to the above contents, and obvious changes, replacements or substitutions based on the above contents do not exceed the scope covered by the technical solutions of the present invention; without departing from the concept of the present invention.
Claims
1. A safe and efficient elevator electrical safety device grounding detection circuit, characterized in that: It includes a ground signal acquisition circuit, a first electric control switch, a power supply, a signal processing circuit, a second electric control switch and an indication circuit; The output end of the ground signal acquisition circuit is connected to the input end of the signal processing circuit; The output terminal of the signal processing circuit is connected to the control terminal of the second electronically controlled switch; The second electronically controlled switch is used to control the on / off of the control circuit and the indication circuit of the first electronically controlled switch; The first electronically controlled switch is used to control the on / off of the ground signal acquisition circuit; The power supply is used to supply power to the first electronically controlled switch, the signal processing circuit, the second electronically controlled switch and the indication circuit; The indicating circuit is used to indicate the detection result of the ground detection.
2. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 1, characterized in that: The ground signal acquisition circuit includes a DC acquisition branch, an AC acquisition branch and a single-pole multi-throw switch.
3. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 2, characterized in that: The DC acquisition branch includes a Hall sensor circuit, a first DC wiring branch and a second DC wiring branch; The Hall sensor circuit includes an iron core, a first primary coil and a secondary coil; A first end of the first primary coil is connected to the first DC wiring branch, and a second end of the first primary coil is connected to the second DC wiring branch via the first electronically controlled switch and the single-pole multi-throw switch in sequence, wherein the first electronically controlled switch is connected to a fixed terminal of the single-pole multi-throw switch, and the second DC wiring branch is connected to a first movable terminal of the single-pole multi-throw switch; A plurality of resistors are provided on the first DC wiring branch and the second DC wiring branch, for reducing the current passing through the first primary coil; The two ends of the secondary coil serve as output ends of the ground signal acquisition circuit.
4. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 2, characterized in that: The AC acquisition branch includes a Hall sensor circuit, an AC first wiring branch, an AC second wiring branch, and an AC third wiring branch; The Hall sensor circuit includes an iron core, a second primary coil and a secondary coil; The first end of the second primary coil is connected to the first AC wiring branch via the first electronically controlled switch and the single-pole multi-throw switch in sequence, the first end of the second primary coil is connected to the second AC wiring branch via the first electronically controlled switch and the single-pole multi-throw switch in sequence, and the second end of the second primary coil is connected to the third AC wiring branch, wherein the first electronically controlled switch is connected to the fixed terminal of the single-pole multi-throw switch, the first AC wiring branch is connected to the second movable terminal of the single-pole multi-throw switch, and the second AC wiring branch is connected to the third movable terminal of the single-pole multi-throw switch; A plurality of resistors are provided on the second AC wiring branch and the third AC wiring branch, for reducing the current passing through the second primary coil and improving the withstand voltage capability of the circuit; The two ends of the secondary coil serve as output ends of the ground signal acquisition circuit.
5. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 3 or 4, characterized in that: The signal processing circuit includes a reference circuit, a thirteenth resistor, a differential amplifier and a signal latch circuit; The output terminal of the reference circuit is connected to the positive input terminal of the differential amplifier through the thirteenth resistor; One end of the secondary coil is connected to the inverting input terminal of the differential amplifier, and the other end is connected to the output terminal of the reference circuit; The output end of the differential amplifier is connected to the input end of the signal latch circuit; The output end of the signal latch circuit is connected to the control end of the second electronically controlled switch.
6. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 5, characterized in that: A potentiometer is further connected between the two ends of the secondary coil. One end of the secondary coil is respectively connected to the first fixed end and the sliding end of the potentiometer, and the other end is connected to the second fixed end of the potentiometer.
7. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 1, characterized in that: The second electronically controlled switch includes a unidirectional thyristor, the output end of the signal processing circuit is connected to the control electrode of the unidirectional thyristor, and the unidirectional thyristor is used to control the control current of the first electronically controlled switch and whether the current of the indication circuit is successfully grounded.
8. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 1, characterized in that: The first electrically controlled switch includes a relay, one end of the input circuit of the relay is connected to the power supply, and the other end is controlled by the second electrically controlled switch to be grounded; the output circuit of the relay is connected to the ground signal acquisition circuit using a normally closed connection method, and is used to control the on and off of the ground signal acquisition circuit.
9. The safe and efficient elevator electrical safety device grounding detection circuit according to claim 1, characterized in that: The indicating circuit includes a galvanometer and a buzzer; one end of the galvanometer and the buzzer is connected to the power supply, and the other end of the galvanometer and the buzzer is controlled by the second electronically controlled switch to be grounded.
10. A safe and efficient elevator electrical safety device grounding detection device, characterized in that: Includes: The grounding detection circuit according to any one of claims 1 to 9 is used to detect whether an electrical device is grounded.