CN2266213Y - Electronic thermorelay - Google Patents
Electronic thermorelay Download PDFInfo
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- CN2266213Y CN2266213Y CN 96202023 CN96202023U CN2266213Y CN 2266213 Y CN2266213 Y CN 2266213Y CN 96202023 CN96202023 CN 96202023 CN 96202023 U CN96202023 U CN 96202023U CN 2266213 Y CN2266213 Y CN 2266213Y
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Abstract
The utility model relates to an electronic thermorelay, comprising a current sampling circuit, a voltage transformer isolating circuit, an active accurate half-wave rectification amplifying circuit, a three-phase average value circuit, a three-phase peak value detecting circuit, a current regulating circuit, an inverse time-limit circuit, a voltage comparing amplifying circuit and a turn-off executing circuit. The utility model is characterized in that the electronic thermorelay also comprises a three-phase unbalance protection circuit and a non-overload discharge circuit. The utility model is an updating generation changing product of the electronic thermorelay, and the utility model is suitable for protecting three-phase current serious unbalance resulted from three-phase motor overload, phase loss, three-phase asymmetrical short circuit, etc.
Description
The utility model relates to a kind of electronic thermal relay, is applicable to that three-phase alternating-current motor overload and three-phase unsymmetrical short-circuit and other reasons cause the serious unbalance protection of three-phase current to use.
At present factory's thermal relay commonly used utilizes the work of bimetal leaf thermal deformation principle, and often owing to reasons such as human factor and vibration, mechanical fatigues, usually when thermal relay moved, motor had strained or burnt, and caused bigger economic loss.When former in addition thermal relay is worked, there are not quick protection of direct phase shortage and three-phase unsymmetrical short-circuit and other reasons to cause the serious uneven quick defencive function of three-phase current.
Electronic type electric motor protector in the market generally comprises current sampling circuit, buffer circuit, voltage amplifier circuit, current regulating circuit, inverse time lag circuit, voltage contrasting amplified circuit and shutoff executive circuit.The motor protecter of this structure does not successfully solve unbalance protection of three-phase current problem and over-load inverse time-lag protection problem, and therefore, when phase shortage and various three-phase unsymmetrical short-circuit occurring, it is unreliable to protect, and overload protection produces misoperation.
The utility model purpose is to be to provide a kind of sensitivity, reliable, accurate, complete, the little current mode electronic thermal relay of volume of function, to overcome bimetal thermal relay and existing electronic type electric motor protector defective.
The technical solution of the utility model: 1, between three-phase average value filtering circuit, current regulating circuit, voltage contrasting amplified circuit, connect the three-phase imbalance protective circuit, realize the serious uneven protection fast of three-phase currents such as phase shortage, phase ground short circuit; 2, at inverse time lag circuit two ends non-overload discharge circuit is set, for the change simulating motor heating in winding situation that realizes the electric capacity electric weight is given security; 3, with the thermal relay thermal element as the current sampling transducer, linearity, precision height; 4, adopt active accurate halfwave rectifier amplifying circuit, realize micro-signal high accuracy rectification amplification; 5, adopt the three-phase peak-detector circuit, realize that overcurrent inverse time lag circuit input end voltage depends on the maximum phase current value; 6, adopt three-phase mean value rectification circuit, suitable time-delay when providing reference voltage and phase shortage for the three-phase imbalance protective circuit, 7, adopt potentiometer to regulate current value, realize that the potentiometer center tap voltage is relevant with overload magnification, irrelevant with the motor rated current.
Detailed content is illustrated that by following embodiment present embodiment is selected protection motor rated current 22A electronic thermal relay for use.
Fig. 1 is electronic thermal relay, alternating current motor and low-voltage electrical apparatus control circuit operation principle block diagram.
Fig. 2 is that the electronic thermal relay operation principle is always schemed.
By Fig. 1, Fig. 2; present embodiment is one and has the electronic thermal relay that overload, the phase failure, three-phase unsymmetrical short-circuit and other reasons cause the serious unbalance protection function of three-phase current that electronic circuit comprises current sampling circuit, voltage transformer buffer circuit, active accurate halfwave rectifier amplifying circuit, three-phase average value filtering circuit, three-phase peak-detector circuit, current regulating circuit, inverse time lag circuit, voltage contrasting amplified circuit and shutoff executive circuit.Connect the three-phase imbalance protective circuit between three-phase average value filtering circuit, current regulating circuit, the voltage contrasting amplified circuit.This circuit is made up of integrated voltage comparator N1, N2, N3, and its anode connects three-phase average value filtering circuit capacitance C1 anode respectively, and negative terminal is connected on current regulating circuit resistance R 8 hot ends simultaneously, output termination voltage contrasting amplified circuit voltage-stabiliser tube V1 hot end.The purpose that this circuit is set is the serious uneven operating state of three-phase current (as short circuit between phase shortage, two alternate short circuits, phase and ground etc.) time to occur at motor to protect.As three-phase A, B, C is arbitrary when phase shortage occurring mutually, it is zero potential that this phase average value filtering circuit capacitance C1 goes up voltage drop, current regulating circuit R8 hot end voltage depends on that the three-phase peak-detector circuit keeps capacitor C 2 voltages, therefore the positive terminal voltage of this integrated voltage comparator of three-phase imbalance protective circuit is lower than negative terminal voltage, and the original high potential (voltage-stabiliser tube V1 voltage stabilizing value) of output electricity becomes in zero potential; The positive terminal voltage of voltage contrasting amplified circuit integrated operational amplifier T4 is higher than negative terminal voltage, its output is a high potential by original zero potential upset, make shutoff carry out the actuating of relay through triode V2 and base resistance R13 thereof, cut off the three-phase main power source by low-voltage electrical apparatus control circuit A.C. contactor.As three-phase A; B; C is arbitrary when shorted to earth occurring mutually; big electric current will cause this mutually active accurate halfwave rectifier amplifying circuit integrated operational amplifier output current potential sharply to rise and be saturated rapidly; by the three-phase peak-detector circuit; current regulating circuit resistance R 8 hot end current potentials sharply rise; because detector diode buffer action; voltage on the two-phase average value filtering circuit capacitance C1 remains unchanged in addition; design current regulating circuit resistance R 7; R8; potentiometer RP parameter; this two-phase integrated voltage comparator negative terminal voltage of three-phase imbalance protective circuit is higher than positive terminal voltage; output is overturn in zero potential by high potential (voltage-stabiliser tube V1 voltage stabilizing value); make the execution actuating of relay through voltage contrasting amplified circuit and shutoff executive circuit, cut off the three-phase main power source rapidly by A.C. contactor.If during two alternate short circuits; biphase current sharply increases; according to single-phase shorted to earth analysis; make another phase integrated voltage comparator output zero potential in the three-phase imbalance protective circuit equally; make the execution actuating of relay through voltage contrasting amplified circuit and shutoff executive circuit, A.C. contactor cuts off the three-phase main power source.If A, B, C three-phase current occur serious uneven; as long as make three-phase imbalance protective circuit integrated voltage comparator N1 or N2 or N3 negative terminal current potential be higher than positive terminal potential; zero potential will appear in its output; carry out the actuating of relay through voltage contrasting amplified circuit and shutoff, A.C. contactor cuts off the three-phase main power source.Because electronic type motor protector short-circuit protection designs according to short circuit current and motor rated current ratio at present, therefore, must avoid the motor starting electric current.Technical solution adopted in the utility model; be to utilize the three-phase current unbalance principle; as long as wherein one mutually or biphase current during greater than other two-phase or a mutually a certain multiple; the Electronic Protection circuit just plays a role; phase shortage, three-phase unsymmetrical short-circuit and the serious non-equilibrium state of other generation three-phase currents are unified in same circuit, are that the utility model technology is different from and key character of prior art.Inverse time lag circuit two ends also connect a non-overload discharge circuit, and this circuit is made up of integrated voltage comparator N4 and output resistance R 9 thereof.The positive termination current regulating circuit of integrated voltage comparator potentiometer RP centre cap, negative terminal connects voltage contrasting amplified circuit voltage-stabiliser tube V1 hot end, and output connects inverse time lag circuit delay capacitor C 3 anodes through R9.The series circuit that the inverse time lag circuit is made up of voltage-stabiliser tube V3 and resistance R 11 and resistance R be 10 in parallel, be in series with delay capacitor C3 and form.Experiment showed, as long as accurately calculate the said elements parameter, just can make this electronic thermal relay anti-time limit characteristic near former bimetal thermal relay anti-time limit characteristic.The purpose of setting up non-overload discharge circuit is by this circuit delay capacitor C3 anode to be clamped at zero potential when being the non-overload of motor, a discharge paths over the ground is provided for delay capacitor C3, with charge constant and discharge time constant simulating motor temperature rise and fall time constant, with voltage analog motor temperature on the capacitor C 3, when the motor operating current did not have overrate, the voltage on the electric capacity was always zero.Existing electronic type electric motor protector overload protection is the series-parallel circuit that utilizes voltage-stabiliser tube, resistance, electric capacity to form, because the voltage-stabiliser tube electric leakage, and interference signal slowly rises capacitance voltage, causes misoperation.Do not provide an electric charge to discharge branch road to electric capacity, capacitance voltage is difficult to the simulating motor temperature rise.Therefore, at inverse time lag circuit two ends and to connect non-overload discharge circuit be that the utility model technology is different from another key character of prior art.
Current sampling circuit adopts former thermal relay thermal element RA, RB, RC as the current sampling transducer among Fig. 1, Fig. 2, RA, RB, RC are connected in the motor main circuit respectively, its two terminations isolated voltage transformer TV1, TV2, TV3's is elementary, minute-pressure on the thermal element is fallen and can be reflected alternating current motor operating current size truly, electronic thermal relay is operated in the low-grade fever state, and energy-saving effect is dignitary particularly.The accurate halfwave rectifier amplifying circuit in the source that between voltage transformer buffer circuit and three-phase peak-detector circuit, is connected to, this circuit by integrated operational amplifier T1, T2, T3 and output thereof, negative terminal, hold between series resistance R3, R4 form.Integrated operational amplifier T1, T2, T3 anode link to each other with voltage transformer buffer circuit isolating transformer TV1, TV2, TV3 level respectively, and output links to each other with three-phase peak-detector circuit detector diode VD anode respectively.The purpose that this circuit is set is carried out halfwave rectifier with the isolating transformer secondary voltage on the one hand; on the other hand this voltage high-fidelity is amplified; when even motor is operated in zero load; also can obtain bigger d. c. voltage signal at its output; take current transformer to obtain voltage signal with electronic type motor protector in the market and compare, have tangible advantage (distortion is little, amplitude is big, linearity).Connect the three-phase peak-detector circuit between active accurate halfwave rectifier amplifying circuit and the current regulating circuit, current-limiting resistance R6, detection capacitor C 2 by three-phase detector diode (VD) and series connection with it are formed, its input (three-phase detector diode VD anode) is connected to source accurate halfwave rectifier amplifying circuit integrated operational amplifier T1, T2, T3 output, and output (detection capacitor C 2 anodes) connects current regulating circuit potentiometer CP hot end.The purpose first that this circuit is set is that potentiometer RP center tap voltage depends on maximum that phase crest voltage of the accurate halfwave rectifier amplifying circuit of three-phase active voltage magnitude in the current regulating circuit; It two is to provide variable reference dc voltage for three-phase imbalance protective circuit integrated voltage comparator N1, N2, N3 negative terminal.Connect three-phase average value filtering circuit between active accurate halfwave rectifier amplifying circuit and the three-phase imbalance protective circuit, be composed in series by current-limiting resistance R5 and filter capacitor C1.Current-limiting resistance R5 is connected to source accurate halfwave rectifier amplifying circuit integrated operational amplifier T1, T2, T3 output, and filter capacitor C1 anode connects the integrated voltage ratio of three-phase imbalance protective circuit respectively than N1, N2, N3 anode.Design this circuit purpose: first three-phase imbalance protective circuit integrated voltage comparator anode provides variable DC reference voltage; It two is when phase shortage and since capacitor C 1 by resistance R 5 to integrated operational amplifier T1, T2, the discharge of T3 output, realize the suitable time-delay time, avoid moment phase shortage misoperation.Connect current regulating circuit between three-phase peak-detector circuit and the inverse time lag circuit, be composed in series by potentiometer RP and resistance R 7, R8.The integrated electric comparator N1 of resistance R 8 high potential termination three-phase imbalance protective circuits, N2, N3 negative terminal; potentiometer RP centre cap connects non-overload discharge circuit integrated voltage comparator N4 anode, potentiometer RP high potential termination three-phase peak-detector circuit detection capacitor C 2 anodes.This circuit purpose is set is; first inverse time lag circuit input end voltage signal size depends on current regulating circuit potentiometer RP centre cap position; in a certain current range to the motor of different rated current; as long as change potentiometer RP centre cap position; just can obtain same output voltage signal; this voltage and motor power (output) are irrelevant; relevant with the motor load multiple; reduced the electronic thermal relay current specification; give to produce and use brings great convenience, it two is to be three-phase imbalance protective circuit integrated voltage comparator N1; N2; the N3 negative terminal provides a variable dc reference dividing potential drop.
In sum, this electronic thermal relay has the following advantages:
1, has disconnected phase, three-phase unsymmetrical short-circuit and other cause three-phase current serious Uneven fast protection.
2, utilize electronic component to realize the bimetal thermal relay inverse time-lag protection, Stable, reliable, parameter discrete is little, and the life-span is long.
3, volume is little, and is easy for installation etc., and therefore, this product is former thermal relay of replacement and the various electronic type electric motor protector novel electron thermal relay with very high market popularization value.
Claims (6)
1, a kind of electronic thermal relay, electronic circuit comprises current sampling circuit, the voltage transformer buffer circuit, active accurate halfwave rectifier amplifying circuit, three-phase average value filtering circuit, the three-phase peak-detector circuit, current regulating circuit, inverse time lag circuit, voltage contrasting amplified circuit, turn-off executive circuit, it is characterized in that this electronic thermal relay also comprises three-phase imbalance protective circuit and non-overload discharge circuit; The three-phase imbalance protective circuit is made up of integrated voltage comparator (N1, N2, N3); Integrated voltage comparator (N1, N2, N3) anode is connected on three-phase average value filtering circuit capacitance (C1) anode respectively; Negative terminal is connected on current regulating circuit resistance (R8) hot end; Output is connected on voltage contrasting amplified circuit voltage-stabiliser tube (V1) hot end; Non-overload discharge circuit is made up of integrated voltage comparator (N4) and its output resistance (R9); Positive termination current regulating circuit potentiometer (RP) centre cap of integrated voltage comparator (N4), negative terminal connects voltage contrasting amplified circuit voltage-stabiliser tube (V1) hot end, and output connects inverse time lag circuit delay electric capacity (C3) anode by resistance (R9).
2,, it is characterized in that current sampling circuit adopts thermal relay thermal element (RA, RB, RC), is connected in the three-phase main circuit according to claims 1 described electronic thermal relay.
3 according to claims 1 described electronic thermal relay, it is characterized in that active accurate halfwave rectifier amplifying circuit by integrated operational amplifier (T1, T2, T3) and output thereof, negative terminal, between series resistance (R3, R4) form; Integrated operational amplifier (T1, T2, T3) anode connects voltage transformer buffer circuit voltage transformer (TV1, TV2, TV3) output respectively, and output connects three-phase peak-detector circuit detector diode (VD) anode respectively.
4, according to claims 1 described electronic thermal relay, it is characterized in that what the three-phase peak-detector circuit was composed in series by detector diode (VD), current-limiting resistance (R6) and detection electric capacity (C2), detector diode (VD) connects anode at active accurate halfwave rectifier amplification circuit output end, positive termination current regulating circuit potentiometer (RP) hot end of detection electric capacity (C2).
5,, it is characterized in that what the three-phase averaging circuit was composed in series by current-limiting resistance (R5) and filter capacitor (C1) according to claims 1 described electronic thermal relay; Current-limiting resistance (R5) is connected on active accurate halfwave rectifier amplification circuit output end, and filter capacitor (C1) anode is connected to three-phase imbalance protective circuit integrated voltage comparator (N1, N2, N3) anode respectively.
6,, it is characterized in that what current regulating circuit was composed in series by potentiometer (RP) and resistance (R7, R8) according to claims 1 described electronic thermal relay; Resistance R 8 high potential termination three-phase imbalance protective circuit integrated voltage comparator negative terminals, potentiometer (RP) centre cap connects non-overload discharge circuit integrated voltage comparator (N4) anode, potentiometer (RP) high potential termination three-phase peak-detector circuit output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96202023 CN2266213Y (en) | 1996-02-09 | 1996-02-09 | Electronic thermorelay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96202023 CN2266213Y (en) | 1996-02-09 | 1996-02-09 | Electronic thermorelay |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2266213Y true CN2266213Y (en) | 1997-10-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96202023 Expired - Fee Related CN2266213Y (en) | 1996-02-09 | 1996-02-09 | Electronic thermorelay |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2266213Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1331289C (en) * | 2001-03-13 | 2007-08-08 | 李相明 | Universal overcurrent protector for high-stability electrical appliances |
| CN103401217A (en) * | 2013-08-07 | 2013-11-20 | 浙江纪元电力自动化科技有限公司 | Intelligent motor protector |
| CN104897328A (en) * | 2015-05-17 | 2015-09-09 | 成都诚邦动力测试仪器有限公司 | Eddy current power-measuring system based on diode symmetry detection circuit |
| CN117134295A (en) * | 2023-07-10 | 2023-11-28 | 中国矿业大学 | Solid-state switch system of underground motor and emergency stop protection control method thereof |
-
1996
- 1996-02-09 CN CN 96202023 patent/CN2266213Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1331289C (en) * | 2001-03-13 | 2007-08-08 | 李相明 | Universal overcurrent protector for high-stability electrical appliances |
| CN103401217A (en) * | 2013-08-07 | 2013-11-20 | 浙江纪元电力自动化科技有限公司 | Intelligent motor protector |
| CN103401217B (en) * | 2013-08-07 | 2018-01-09 | 浙江纪元电气科技股份有限公司 | Intelligent motor protector |
| CN104897328A (en) * | 2015-05-17 | 2015-09-09 | 成都诚邦动力测试仪器有限公司 | Eddy current power-measuring system based on diode symmetry detection circuit |
| CN117134295A (en) * | 2023-07-10 | 2023-11-28 | 中国矿业大学 | Solid-state switch system of underground motor and emergency stop protection control method thereof |
| CN117134295B (en) * | 2023-07-10 | 2024-04-16 | 中国矿业大学 | Solid-state switch system of underground motor and emergency stop protection control method thereof |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C53 | Correction of patent for invention or patent application | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: PATENTEE ADDRESS; FROM: NO. 5, LANE 111, JIANSHEDONG ROAD, LEQING CITY, ZHEJIANG PROVINCE TO: ROOM 1707, HOUSE 111, JIXIANGLI, ZHAOWAIDA STREET, CHAOYANG DISTRICT, BEIJING CITY, 100020 |
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| CP03 | Change of name, title or address |
Address after: 100020, Beijing, Chaoyang District, Wai Avenue, auspicious lane, 111 floor, room 1707 Patentee after: Wang Zhengcun Address before: No. 111, Lane 5, Jianshe East Road, Yueqing, Zhejiang Patentee before: Wang Zhengcun |
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| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |