Electric appliance current overload protection device
By quickly disconnecting the overload current through the current amplification circuit and control circuit, the problem of current surge when electrical equipment is overloaded is solved, realizing rapid protection and autonomous recovery circuits, and improving the working accuracy and lifespan of the equipment.
Patent Information
- Application Number
- CN202422944603.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2034-11-29
AI Technical Summary
When existing electrical equipment is overloaded, the overload current will cause current surges to the internal components, affecting the working accuracy and lifespan. Moreover, the existing protection devices have a slow response speed and cannot disconnect the circuit in time.
It employs a current amplification circuit and a control circuit to quickly disconnect the circuit between the live wire and the electrical appliance when the current is overloaded through the contacts of a normally closed relay, and automatically restore the circuit connection after the current returns to normal. It also uses a capacitor to delay the contact opening time to avoid overload impact.
It enables rapid disconnection of overload current, protects electrical equipment, avoids current surges, improves the working accuracy and lifespan of equipment, and also has an autonomous recovery function.
Smart Images
Figure CN223527765U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the field of current overload protection, and relates to an electric appliance current overload protection device. BACKGROUND
[0002] In the prior art, the current overload protection between some electric appliances connected with commercial power generally adopts a fuse or an overload protector. One kind of overload protector is an electromagnetic overcurrent relay, that is, when the current exceeds a threshold value, the electromagnetic overcurrent relay is attracted by an electromagnet to disconnect the circuit. Another kind of overload protector detects the current in the circuit, and a microprocessor receives a detection signal to control a relay or a circuit breaker in the circuit to open or close.
[0003] The above-mentioned methods actually disconnect the circuit when the current overload has flowed to the electric appliance. The current overload in a short time generally does not cause damage to the device, but for some precision machining devices, the internal elements are subjected to current impact each time the current overload occurs, which affects the working precision and service life of the device. SUMMARY
[0004] To overcome the defects in the prior art, the utility model provides an electric appliance current overload protection device which can quickly act and independently recover the circuit.
[0005] To achieve the above technical purposes, the utility model provides an electric appliance current overload protection device. The electric appliance current overload protection device comprises a protection resistor, a rectifier circuit, a current amplification circuit, a control circuit, a normally closed relay and a capacitor. The protection resistor is connected with a live wire. The rectifier circuit is connected in series with the protection resistor, and the negative electrode of the rectifier circuit is grounded. The current amplification circuit, the signal end of the current amplification circuit is connected with the positive electrode of the rectifier circuit. The control circuit is connected with the output end of the current amplification circuit, and the control circuit is configured to receive an amplified current from the output end of the current amplification circuit and control the circuit between the control circuit and a control power supply to be conducted or interrupted. The coil of the normally closed relay is arranged on the circuit between the control circuit and the control power supply, and the contact of the normally closed relay is connected in series with the live wire. The capacitor is connected in series with the live wire before the contact of the normally closed relay.
[0006] Preferably, the electric appliance current overload protection device further comprises a shunt resistor, and the shunt resistor is arranged between the rectifier circuit and the current amplification circuit.
[0007] The shunt resistor comprises a first resistor and a second resistor, one end of the first resistor is electrically connected to an output end of the current amplification circuit, the other end of the first resistor is grounded, and the second resistor is connected in series to a circuit between an output end of the rectifier circuit and the current amplification circuit.
[0008] Preferably, the control circuit comprises a thyristor, an anode of the thyristor is electrically connected to a positive pole of the control power supply, a cathode of the thyristor is electrically connected to a coil of the normally closed relay, a control electrode of the thyristor is electrically connected to an output end of the current amplification circuit, and the coil of the normally closed relay is electrically connected to a negative pole of the control power supply.
[0009] Preferably, the current amplification circuit comprises a common emitter amplification circuit, and the common emitter amplification circuit is further electrically connected to the control power supply.
[0010] Preferably, a filter capacitor is arranged between the rectifier circuit and the current amplification circuit, one end of the filter capacitor is electrically connected to a connection point of a positive pole of the rectifier circuit and the current amplification circuit, and the other end of the filter capacitor is grounded.
[0011] Preferably, contacts of the normally closed relay are arranged on the live wire after the protection resistor and the live wire connection position.
[0012] The utility model discloses a current amplification circuit and control circuit are adopted, can open the contact of normally closed relay when the current overload in the live wire, make the circuit of live wire and electrical appliance quick break, avoid the overload current impact electrical equipment.
[0013] The utility model discloses a current amplification circuit and control circuit are adopted, can open the contact of normally closed relay when the current overload in the live wire, make the circuit of live wire and electrical appliance quick break, avoid the overload current impact electrical equipment.
[0014] The capacitor is arranged on the live wire before the contact of the normally closed relay, and the capacitor does not affect the passage of alternating current, but when the current of the alternating current increases, the transmission speed of the alternating current can be reduced, time is provided for opening of the contact of the normally closed relay, and the device is prevented from being impacted by the overload current. BRIEF DESCRIPTION OF DRAWINGS
[0015] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or related technologies, the drawings needed to be used in the embodiment or related technology description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.
[0016] Figure 1 It is a structural diagram of the utility model;
[0017] Figure 2 It is another structural diagram of the utility model;
[0018] Figure 3 Another structure diagram of the utility model. DETAILED DESCRIPTION
[0019] In order to make the above objectives, characteristics and advantages of the utility model more apparent, obvious and easy to understand, the technical solutions in the utility model embodiments will be clearly and completely described below with reference to the drawings in the utility model embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the utility model.
[0020] In the description of the utility model, it is understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.
[0021] The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0022] Embodiment 1
[0023] As Figure 1As shown, the embodiment provides an electrical appliance current overload protection device. The electrical appliance current overload protection device comprises a protection resistor R1, a rectifier circuit D, a current amplification circuit 1, a control circuit, a normally closed relay KM and a capacitor C3. The protection resistor R1 is electrically connected with the live wire L. The rectifier circuit D is connected in series with the protection resistor R1, and the negative electrode of the rectifier circuit D is grounded. The current amplification circuit 1, the signal end of the current amplification circuit 1 is electrically connected with the positive electrode of the rectifier circuit D. The control circuit is electrically connected with the output end of the current amplification circuit 1, and the control circuit is configured to receive the amplified current from the output end of the current amplification circuit 1, and under the control of the amplified current, the circuit between the control circuit and the control power supply is turned on or interrupted. The coil of the normally closed relay KM is arranged on the circuit between the control circuit and the control power supply, and the contact of the normally closed relay KM is connected in series with the live wire L. The capacitor C3 is connected in series to the live wire L before the contact of the normally closed relay KM.
[0024] Exemplarily, for single-phase electricity, the resistance of the protection resistor R1 can be 1KΩ, and the rectifier circuit D can adopt a diode rectifier circuit D, one of the two input ends of the diode rectifier circuit D is electrically connected with the other end of the protection resistor R1, and the other of the two input ends is electrically connected with the zero line.
[0025] The output ends of the diode rectifier circuit D are provided with the current amplification circuit 1, and the output current of the diode rectifier circuit D is less than 0.5A. The current amplification circuit 1 is electrically connected with the control power supply and the output end positive electrode of the rectifier circuit D, the current amplification circuit 1 receives the output end current of the rectifier circuit D and outputs an amplified current, the amplified current is received by the control circuit, and the control circuit opens or closes the contact of the normally closed relay KM on the live wire L under the control of the amplified current, for example, when the amplified current is greater than a threshold current, the contact of the normally closed relay KM is opened to disconnect the live wire L, and when the amplified current is less than the threshold current, the contact of the normally closed relay KM remains closed to keep the live wire L in a conducting state.
[0026] It can be understood that, in the case that the load of the live wire L is constant, when the current overload occurs, the increased current on the protection resistor R1 and the current of the load are fixed in ratio. That is to say, the amplified current and the current of the live wire L are linearly related, and the size of the threshold current is limited, when the amplified current exceeds the threshold current, the live wire L is controlled to be disconnected, therefore, according to the maximum value of the current of the live wire L, the threshold current can be calculated.
[0027] The electrical appliance current overload protection device can be arranged between the corresponding electrical appliance and the live wire L, and can provide current overload protection for the corresponding electrical appliance, and has the advantages of fast action and high control precision.
[0028] Embodiment 2
[0029] As Figure 2 shown in the embodiment 1, the electric appliance current overload protection device further comprises a shunt resistance, the shunt resistance is arranged between the rectifier circuit D and the current amplification circuit 1.
[0030] The shunt resistance comprises a first resistance R8 and a second resistance R7, one end of the first resistance R8 is electrically connected with the output end of the current amplification circuit 1, the other end of the first resistance R8 is grounded, and the second resistance R7 is connected in series to the circuit between the output end of the rectifier circuit D and the current amplification circuit 1.
[0031] In the embodiment, by controlling the values of the first resistance R8 and the second resistance R7, the current value input to the current amplification circuit 1 can be adjusted, so that the input current of the current amplification circuit 1 can be controlled according to the needs, and the linear correlation between the amplified current and the current of the live wire L can be ensured. The shunt resistance further improves the flexibility of the electric appliance current overload protection device.
[0032] Embodiment 3
[0033] On the basis of the embodiment 1 or the embodiment 2, the control circuit comprises a thyristor VT, the anode of the thyristor VT is electrically connected with the positive pole of the control power supply, the cathode of the thyristor VT is electrically connected with the coil of the normally closed relay KM, the control electrode of the thyristor VT is electrically connected with the output end of the current amplification circuit 1, and the coil of the normally closed relay KM is electrically connected with the negative pole of the control power supply.
[0034] The utility model needs to calculate threshold current according to corresponding electric appliance, protection resistance R1, rectifier circuit D, current amplification circuit 1 and shunt resistance, when the amplified current is greater than or equal to threshold current, the thyristor VT is turned on, when the amplified current is less than threshold current, the thyristor VT is cut off. When the thyristor VT is turned on, the control power supply, the control circuit and the coil of the normally closed relay KM form a closed loop, the contact of the normally closed relay KM is opened, when the thyristor VT is cut off, the circuit between the control power supply and the coil of the normally closed relay KM is disconnected, and the contact of the normally closed relay KM is closed. That is, when the current in the live wire L is overloaded, the amplified current is greater than threshold current, the thyristor VT is turned on, and the live wire L is disconnected, when the current in the live wire L is normal (less than the current of overload), the amplified current is less than threshold current, the thyristor VT is cut off, and the live wire L remains conductive.
[0035] Embodiment 4
[0036] On the basis of the embodiment 1, the embodiment 2 or the embodiment 3, the current amplification circuit 1 of the electric appliance current overload protection device comprises a common emitter amplification circuit, and the common emitter amplification circuit is further electrically connected with the control power supply.
[0037] The common-emitter amplifier circuit is a circuit structure well-known to those skilled in the art, and its circuit structure will not be described in detail again. In this embodiment, the amplification factor of the common-emitter amplifier circuit can be selected as needed.
[0038] Example 5
[0039] like Figure 3 As shown, based on Embodiment 1, Embodiment 2, Embodiment 3 or Embodiment 4, a filter capacitor C4 is provided between the rectifier circuit D and the current amplification circuit 1 of the electrical current overload protection device described in this embodiment. One end of the filter capacitor C4 is electrically connected to the positive terminal of the rectifier circuit D and the connection point of the current amplification circuit 1, and the other end of the filter capacitor C4 is grounded.
[0040] To avoid the influence of noise in the live wire L, and to prevent the current at the peak of the current from being detected by this invention and causing the normally closed relay KM to open and close its contacts in a very short time, a filter capacitor C4 can be provided between the rectifier circuit D and the current amplifier circuit 1. Multiple filter capacitors C4 can be provided in parallel.
[0041] Example 6
[0042] Based on Embodiment 1, Embodiment 2, Embodiment 3 or Embodiment 4, the normally closed relay KM of the electrical current overload protection device described in this embodiment has its contacts located on the live wire L after the connection position of the protection resistor R1 and the live wire L.
[0043] Specifically, the live wire L is electrically connected to the protective resistor R1 and the electrical appliance. The contacts of the normally closed relay KM are located on the live wire L between the live wire L, the protective resistor R1, and the electrical appliance. The electrical current overload protection device described in this invention is connected in parallel with the electrical appliance to the live wire L. When the current on the live wire L is overloaded, the electrical current overload protection device can disconnect the circuit between the electrical appliance and the live wire L. Alternatively, the electrical current overload protection device can remain connected to the live wire L and continue operating. When the current on the live wire L returns to normal, the electrical current overload protection device can reconnect the circuit between the electrical appliance and the live wire L, allowing the electrical appliance to operate normally.
[0044] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
[0045] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.
Claims
1. An electrical current overload protection device for an electrical appliance, characterized in that, The application relates to an electric appliance current overload protection device, which comprises the following components: a protection resistor electrically connected to a live wire; a rectifier circuit connected in series with the protection resistor, the negative pole of the rectifier circuit being grounded; a current amplification circuit, the signal end of which is electrically connected to the positive pole of the rectifier circuit; a control circuit electrically connected to the output end of the current amplification circuit, the control circuit being configured to receive an amplified current from the output end of the current amplification circuit and to be turned on or interrupted with the control circuit and a control power supply under the control of the amplified current; a normally closed relay, the coil of which is arranged on the circuit between the control circuit and the control power supply, and the contact of which is connected in series to the live wire; a capacitor connected in series to the live wire before the contact of the normally closed relay.
2. The electrical current overload protection device of claim 1, wherein, The electric appliance current overload protection device further comprises a shunt resistor arranged between the rectifier circuit and the current amplification circuit. The shunt resistor comprises a first resistor and a second resistor, one end of the first resistor being electrically connected to the output end of the current amplification circuit, the other end of the first resistor being grounded, and the second resistor being connected in series to the circuit between the output end of the rectifier circuit and the current amplification circuit.
3. The electrical current overload protection device of claim 1, wherein, The control circuit comprises a thyristor, the anode of the thyristor being electrically connected to the positive pole of the control power supply, the cathode of the thyristor being electrically connected to the coil of the normally closed relay, the control electrode of the thyristor being electrically connected to the output end of the current amplification circuit, and the coil of the normally closed relay being electrically connected to the negative pole of the control power supply.
4. An electrical current overload protection device according to any one of claims 1 to 3, characterised in that, The current amplification circuit comprises a common-emitter amplification circuit, which is further electrically connected to the control power supply.
5. The electrical current overload protection device of claim 4, wherein, A filter capacitor is arranged between the rectifier circuit and the current amplification circuit, one end of the filter capacitor being electrically connected to the connection point of the positive pole of the rectifier circuit and the current amplification circuit, and the other end of the filter capacitor being grounded.
6. The electrical current overload protection device of claim 5, wherein, The contact of the normally closed relay is arranged on the live wire after the connection position of the protection resistor and the live wire.