CN203352509U - Drive circuit of motor soft starter - Google Patents
Drive circuit of motor soft starter Download PDFInfo
- Publication number
- CN203352509U CN203352509U CN 201320433784 CN201320433784U CN203352509U CN 203352509 U CN203352509 U CN 203352509U CN 201320433784 CN201320433784 CN 201320433784 CN 201320433784 U CN201320433784 U CN 201320433784U CN 203352509 U CN203352509 U CN 203352509U
- Authority
- CN
- China
- Prior art keywords
- thyristor
- drive circuit
- optocoupler
- rear end
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Landscapes
- Motor And Converter Starters (AREA)
Abstract
A drive circuit of a motor soft starter comprises three thyristor drive circuits which are the same. The three thyristor drive circuits are respectively connected with thyristor sets, and each thyristor set has a pair of thyristors which are in parallel connection in reverse directions. each thyristor drive circuit comprises an optical coupler input terminal drive circuit, an optical coupler rear end pressure limiting protection circuit and two gate drive circuits with the same structure. One end of the optical coupler input terminal drive circuit is connected with an input terminal power supply, and the other end is connected with a processor CPU; the optical coupler input terminal drive circuit is isolated from the optical coupler rear end pressure limiting protection circuit by three optical couplers; two ends of the optical coupler rear end pressure limiting protection circuit are respectively connected with the two gate drive circuits; and the two gate drive circuits are respectively connected with two ends of each thyristor set and are respectively connected with the gate poles of the pair of thyristors which are in parallel connection in reverse directions in each thyristor set. The structure is simple, power consumption noise is low, contact fusing of a bypass switch is prevented, and an arc protection function is provided.
Description
Technical field
The utility model relates to Low Voltage Electrical Apparatus, is specifically related to motor starter, particularly a kind of drive circuit of motor soft starter.
Background technology
As everyone knows, during the threephase asynchronous machine across-the-line starting, electric current can reach 5～8 times usually, even larger, produces the great impact electric current, and the electrical network with in a system is produced to very large fluctuation, and whole drive system, equipment are produced to harmful effect.Soft starter is that a kind of current collection motor soft start, soft stop, light-load energy saving and multi-protective function are in the novel control device of electric motor of one.After adopting soft starter, the problems referred to above are resolved, and starting current can be arranged and limit.Soft starter is the renewal product of the starters such as star-delta starter, auto-coupling reduced voltage starter.Be provided with drive circuit in soft starter, existing motor soft starter driving circuit structure complexity, power consumption and noise are larger, and do not have preventing fusing and preventing the defencive function that the arcing phenomenon produces of by-pass switch contact.
The utility model content
The purpose of this utility model is to overcome the defect of prior art; provide a kind of simple in structure; noise low in energy consumption is little; can prevent the drive circuit of by-pass switch at the soft starter of release and the fusing of adhesive moment contact and generation arcing phenomenon; the drive circuit of soft starter of the present utility model has effectively been protected the contact of by-pass switch, has improved the useful life of by-pass switch.
For achieving the above object, the utility model has adopted following technical scheme:
A kind of drive circuit of motor soft starter, comprise the thyristor driving circuit that three tunnels are identical, described three road thyristor driving circuits are connected with three groups of thyristor groups with thyristor of a pair of reverse parallel connection respectively, described three groups of thyristor groups one ends are connected with R, S, T tri-respectively, the other end is connected to three phase electric machine through U, V, W tri-respectively, and the described three every roads of road thyristor driving circuit include optocoupler input drive circuit, optocoupler rear end pressure limited protection circuit and two groups of gate drive circuits that structure is identical; Described optocoupler input drive circuit one end is connected with the input power supply, and the other end is connected with processor CPU; Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations, and each is connected pressure limited protection circuit two ends, described optocoupler rear end with one group of gate drive circuit; Described two groups of gate drive circuits are connected with the thyristor groups two ends respectively and are connected with the gate pole of the thyristor of a pair of reverse parallel connection of thyristor groups respectively.
Further; described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations; described optocoupler input drive circuit comprises that the input of 3 optocouplers and 1 the 8th electric capacity form; between the input of 3 optocouplers the series connection after with the 8th Capacitance parallel connection; the end be connected in parallel a little is connected with the input power supply, and other end tie point is connected in network connection point through the 20 resistance and processor CPU.
Further; described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations; described optocoupler rear end pressure limited protection circuit comprises that the output of 3 optocouplers and 3 piezo-resistances form, and each optocoupler output is connected respectively with after a piezo-resistance parallel connection.
Further, described two groups of gate drive circuits drive respectively the thyristor of a pair of reverse parallel connection in described thyristor groups, wherein, the first gate drive circuit comprises the 5th backward diode, the 7th electric capacity and the 16 resistance in parallel, its end be connected in parallel a little is connected with the tie point of the anode of the second thyristor with the negative electrode K1 of the first thyristor, and the other end be connected in parallel a little is connected through resistance and is connected with an end of optocoupler rear end pressure limited protection circuit with the gate pole G1 of the first thyristor; The second gate drive circuit comprises the 6th backward diode, the 9th electric capacity and the 19 resistance in parallel; its some end that is connected in parallel is connected with the tie point of the anode of the first thyristor with the negative electrode K2 of the second thyristor, and the other end be connected in parallel a little is connected with the gate pole G2 of the second thyristor and is connected with the other end of optocoupler rear end pressure limited protection circuit through resistance.
Further; described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations; described optocoupler rear end pressure limited protection circuit comprises that the output of 3 optocouplers and 3 divider resistances form, and each optocoupler output is connected respectively with after a divider resistance parallel connection.
Further, the power supply of described input power supply is+12V～+ 24V, the electric current I of described optocoupler input
fbe greater than 10mA.
Further, the resistance of described divider resistance is 1M Ω～5M Ω.
The accompanying drawing explanation
Fig. 1 be the utility model electric machine soft starting drive circuit principle schematic
Fig. 2 is the basic principle schematic of the utility model electric machine soft starting
Fig. 3 is the signal waveform schematic diagram that the utility model drive circuit U triggers moment mutually
Fig. 4 is the input electric current and the schematic diagram that concerns that triggers lag time of the utility model optocoupler
Fig. 5 is the utility model drive circuit U current direction schematic diagram when positive half cycle triggers mutually
Current direction schematic diagram when Fig. 6 is the triggering of the utility model drive circuit U phase negative half period
Fig. 7 is the utility model optocoupler schematic internal view
Embodiment
The embodiment provided below in conjunction with accompanying drawing 1 to 4, further illustrate the embodiment of the drive circuit of electric machine soft starting of the present utility model.The drive circuit of electric machine soft starting of the present utility model is not limited to the description of following examples.
Referring to Fig. 1 to 2, the drive circuit of electric machine soft starting of the present utility model, it comprises the thyristor driving circuit that three tunnels are identical, described three road thyristor driving circuits are connected with three groups of thyristor groups with thyristor of a pair of reverse parallel connection respectively, described three groups of thyristor groups one ends are connected with R, S, T tri-respectively, and the other end is connected to three phase electric machine through U, V, W tri-respectively.The described three every roads of road thyristor driving circuit include optocoupler input drive circuit, optocoupler rear end pressure limited protection circuit and two groups of gate drive circuits that structure is identical; Described optocoupler input drive circuit one end is connected with the input power supply, and the other end is connected with processor CPU; Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations, and each is connected pressure limited protection circuit two ends, described optocoupler rear end with one group of gate drive circuit; Two groups of gate drive circuits are connected with the thyristor groups two ends respectively and are connected with the gate pole of the thyristor of a pair of reverse parallel connection of thyristor groups respectively.
Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations, strong and weak electricity for buffer circuit, make the optocoupler input can be maintained and be controlled by light current the conducting of thyristor driving circuit, the strong voltage in electrical network can be born again in the optocoupler rear end simultaneously; Described two groups of gate drive circuits are for alternately triggering the also thyristor of a pair of reverse parallel connection of conducting, and conducting increases gradually, makes the soft start that motor is level and smooth, realized the purpose of starting current limliting and smooth start.
As shown in Figure 1, described three road thyristor driving circuit structures are identical, and the U phase thyristor driving circuit that the existing thyristor groups formed with thyristor SCR1, SCR2 with a pair of reverse parallel connection is connected further describes the drive circuit of electric machine soft starting of the present utility model.
Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 optocoupler U7, U8, U9 isolation; described optocoupler input drive circuit comprises that the input of 3 optocoupler U7, U8, U9 and 1 capacitor C 8 form; in parallel with capacitor C 8 after series connection between the input of 3 optocoupler U7, U8, U9; the end be connected in parallel a little is connected with the input power supply, and other end tie point is connected in network connection point Mu through resistance R 20 with processor CPU.The Mu triggering signal is Low level effective.When CPU sends out triggering signal, Mu is low level, and the input LED lighting of 3 optocoupler U7, U8, U9, provide triggering signal just to optocoupler U7, U8, U9 output.As shown in Figure 7, wherein 01 means the optocoupler input to the schematic internal view of optocoupler, is light-emitting diode, and 02 means the optocoupler output, is anti-parallel thyristor.By light signal, replace the gate pole triggering signal to trigger the anti-parallel thyristor of optocoupler inside.Optocoupler voltage V
frepresentative value is 1.3V, as long as guarantee optocoupler input electric current I
fbe greater than 10mA and just can reliably drive inner anti-parallel thyristor, optocoupler input electric current I
fequal [VCC-(3 * V
f)]/R20 (A), the power supply VCC of described input power supply can for+12V～+ 24V, the present embodiment VCC is+15V.
Described optocoupler rear end pressure limited protection circuit comprises that the output of 3 optocoupler U7, U8, U9 and 3 piezo-resistance RV7, RV8, RV9 form, and each optocoupler output is connected respectively with after a piezo-resistance parallel connection.Described piezo-resistance is for absorbing surge voltage on this circuitry phase or the back-emf of motor, and when conventional voltage, piezo-resistance, in high-impedance state, only has several μ A leakage currents simultaneously.Described piezo-resistance can also substitute with grading resistor, but can only play all pressure effects during grading resistor, can not play the surge voltage at absorption thyristor two ends and the effect of back electromotive force, the two ends of the thyristor of a pair of reverse parallel connection increase the RC absorbing circuit for suppressing surge voltage again, and the resistance of above-mentioned grading resistor is preferably 1M Ω～5M Ω.
Described two groups of gate drive circuit structures are identical, are respectively used to drive two thyristor SCR1, SCR2; Wherein, the first gate drive circuit comprises backward diode D5 in parallel, capacitor C 7 and resistance R 16, its end be connected in parallel a little is connected with the tie point of the anode of the second thyristor SCR2 with the negative electrode K1 of the first thyristor SCR1, and the other end be connected in parallel a little is connected with the gate pole G1 of the first thyristor SCR1 and is connected with an end of optocoupler rear end pressure limited protection circuit through resistance R 17, R15; Capacitor C 7 and resistance R 16 form the RC charge-discharge circuit, and backward diode D5 is for one-way conduction; The second gate drive circuit comprises backward diode D6 in parallel, capacitor C 9 and resistance R 19, its some end that is connected in parallel is connected with the tie point of the anode of the first thyristor SCR1 with the negative electrode K2 of the second thyristor SCR2, and the other end be connected in parallel a little is connected with the gate pole G2 of the second thyristor SCR2 and is connected with the other end of optocoupler rear end pressure limited protection circuit through resistance R 18, R21; Capacitor C 9 and resistance R 19 form the RC charge-discharge circuit, and backward diode D6 is for one-way conduction.Wherein charge and discharge capacitance C7, C9's can be respectively carry out parallel connection with two electric capacity and substitute, to prevent the gate circuit transistor gate overtension, the electric capacity that is former capacity 1/2 with two capacity as the position in capacitor C 7 carries out the timeconstantτ that arrives same RC charge-discharge circuit that uses in parallel.
Because three road thyristor driving circuit principles are duplicate, existing take U phase thyristor driving circuit in conjunction with Fig. 3 and further illustrate the principle of drive circuit as example.Fig. 3 is the signal waveform schematic diagram that the utility model drive circuit U phase thyristor driving circuit triggers moment, comprises triggering signal Mu, thyristor groups both end voltage V to U phase thyristor driving circuit
k2K1waveform and U phase phase voltage are triggering the waveform schematic diagram of moment with reference to waveform.
In the T1 time as shown in Figure 3, in first grid cyclic wave, when at the positive half cycle of U phase phase voltage (Vk2 > Vk1), when CPU sends out triggering signal, Mu is low level, optocoupler U7, U8, U9 input LED lighting, triggering signal is provided just to optocoupler U7, U8, U9 output, the electric current of optocoupler rear end drive circuit is connected with the RC charge-discharge circuit of resistance R 16, capacitor C 7 successively after backward diode D6, resistance R 18, R21, optocoupler U9, U8, U7, resistance R 15, R17, backward diode D5, in reverse blocking state, flows to as shown in Figure 5.The now pressure drop of optocoupler U7, U8, U9 only has several volts, ignores.The gate voltage VG1K1=VK2K1 of the first thyristor SCR1 * (1-e-t/ τ), τ=(R18+R21+R15+R17) * C7 wherein, after several μ s, gate voltage VG1K1 voltage is greater than gate trigger voltage, the first thyristor SCR1 starts conducting so, once after the first thyristor SCR1 conducting, the RC circuit that resistance R 16, capacitor C 7 form just is in discharge condition, VG1K1 voltage just can not continue to rise yet, and the negative electrode K2 positive voltage of using the second thyristor SCR2 drives the gate pole G1 of the first thyristor SCR1.
In the T2 time as shown in Figure 3, when at U phase phase voltage negative half period (Vk1 > Vk2), when CPU sends out triggering signal, Mu is low level, the electric current of optocoupler rear end drive circuit is connected with the RC charge-discharge circuit of resistance R 19, capacitor C 9 successively after backward diode D5, resistance R 17, R15, optocoupler U7, U8, U9, resistance R 21, R18, backward diode D6, in reverse blocking state, flows to as shown in Figure 6.The pressure drop of optocoupler U7, U8, U9 only has several volts, ignores.The second thyristor SCR2 gate voltage VG2K2=VK1K2 * (1-e-t/ τ), τ=(R18+R21+R15+R17) * C9 wherein, after several μ s, gate voltage VG2K2 is greater than gate trigger voltage, after once the second thyristor SCR2 starts conducting the second thyristor SCR2 conducting so, the RC circuit that resistance R 19, capacitor C 9 form just is in discharge condition, VG2K2 voltage also just can not continue to rise, and (the K1 positive voltage drives the gate pole G2 of the second thyristor SCR2 to use the negative electrode of the first thyristor SCR1.
Second grid cyclic wave is also so, the like, cycle alternation triggers and the conducting thyristor, and conducting increases gradually, makes the soft start that motor is level and smooth, has realized the purpose of starting current limliting and smooth start.In the continuous triggering of thyristor and alternate conduction process; motor starts rotation; can produce higher back electromotive force (concrete many high intrinsic parameters by motor and rotating speed determine); see Fig. 2 schematic diagram; be subject in addition the surge voltage that thunderbolt produces on electrical network; above-mentioned back-emf and surge voltage are all absorbed by the piezo-resistance in optocoupler rear end pressure limited protection circuit in Fig. 1 and suppress, and have the effect of protection thyristor and interlock circuit.
Due to motor soft starter drive circuit of the present utility model in the situation that the by-pass switch closure in bypass when operation; the input of optocoupler has 10mA left and right electric current always; large electric current substantially all flows through from by-pass switch; so; if by-pass switch is unexpected, disconnect; be less than in disconnection moment of 100 μ s thyristor can automatic conducting; when the thyristor conducting; the voltage at by-pass switch two ends just is less than 2.5VAC; thereby the contact of protection by-pass switch is melted discharging moment, also not there will be the arcing phenomenon.As shown in Figure 4, wherein tgd triggers lag time for the input electric current of the utility model optocoupler and the relation that triggers lag time, and IF is the input electric current, and input electric current I F is larger, and triggering is shorter lag time.IFT25 ℃ is exactly the static input electric current of this optocoupler in the time of 25 ℃, is a fixed value, is generally 2mA～3mA, and IF is dynamic input electric current, requires to be greater than in principle 10mA.
Motor soft starter drive circuit of the present utility model is based on optocoupler and supporting control circuit, and adopt by means of anode circuit and use the electric network source technical measures, the power supply power consumption of Shi Mei road thyristor driving circuit is down to only 0.25W, three tunnels also only need 0.75W, greatly reduce power consumption and the noise of drive circuit, its weight and area that has reduced drive circuit simple in structure.
Should be understood that: above-described embodiment is just to explanation of the present utility model, rather than, to restriction of the present utility model, any utility model do not exceeded in the utility model connotation scope is created, within all falling into protection range of the present utility model.
Claims (7)
1. the drive circuit of a motor soft starter, comprise the thyristor driving circuit that three tunnels are identical, described three road thyristor driving circuits are connected with three groups of thyristor groups with thyristor of a pair of reverse parallel connection respectively, described three groups of thyristor groups one ends are connected with R, S, T tri-respectively, the other end is connected to three phase electric machine through U, V, W tri-respectively, it is characterized in that:
The described three every roads of road thyristor driving circuit include optocoupler input drive circuit, optocoupler rear end pressure limited protection circuit and two groups of gate drive circuits that structure is identical; Described optocoupler input drive circuit one end is connected with the input power supply, and the other end is connected with processor CPU; Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations, and each is connected pressure limited protection circuit two ends, described optocoupler rear end with one group of gate drive circuit; Described two groups of gate drive circuits are connected with the thyristor groups two ends respectively and are connected with the gate pole of the thyristor of a pair of reverse parallel connection of thyristor groups respectively.
2. the drive circuit of motor soft starter according to claim 1 is characterized in that:
Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations; described optocoupler input drive circuit comprises that the input of 3 optocouplers and 1 the 8th electric capacity form; between the input of 3 optocouplers the series connection after with the 8th Capacitance parallel connection; the end be connected in parallel a little is connected with the input power supply, and other end tie point is connected in network connection point through the 20 resistance and processor CPU.
3. the drive circuit of motor soft starter according to claim 1 is characterized in that:
Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations; described optocoupler rear end pressure limited protection circuit comprises that the output of 3 optocouplers and 3 piezo-resistances form, and each optocoupler output is connected respectively with after a piezo-resistance parallel connection.
4. the drive circuit of motor soft starter according to claim 1 is characterized in that:
Described two groups of gate drive circuits drive respectively the thyristor of a pair of reverse parallel connection in described thyristor groups, wherein, the first gate drive circuit comprises the 5th backward diode, the 7th electric capacity and the 16 resistance in parallel, its end be connected in parallel a little is connected with the tie point of the anode of the second thyristor with the negative electrode K1 of the first thyristor, and the other end be connected in parallel a little is connected through resistance and is connected with an end of optocoupler rear end pressure limited protection circuit with the gate pole G1 of the first thyristor; The second gate drive circuit comprises the 6th backward diode, the 9th electric capacity and the 19 resistance in parallel; its some end that is connected in parallel is connected with the tie point of the anode of the first thyristor with the negative electrode K2 of the second thyristor, and the other end be connected in parallel a little is connected with the gate pole G2 of the second thyristor and is connected with the other end of optocoupler rear end pressure limited protection circuit through resistance.
5. the drive circuit of motor soft starter according to claim 1 is characterized in that:
Described optocoupler input drive circuit and optocoupler rear end pressure limited protection circuit are by 3 light-coupled isolations; described optocoupler rear end pressure limited protection circuit comprises that the output of 3 optocouplers and 3 divider resistances form, and each optocoupler output is connected respectively with after a divider resistance parallel connection.
6. the drive circuit of motor soft starter according to claim 1 is characterized in that:
The power supply of described input power supply is+12V～+ 24V, the electric current I of described optocoupler input
fbe greater than 10mA.
7. the drive circuit of motor soft starter according to claim 5 is characterized in that:
The resistance of described divider resistance is 1M Ω～5M Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320433784 CN203352509U (en) | 2013-07-19 | 2013-07-19 | Drive circuit of motor soft starter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320433784 CN203352509U (en) | 2013-07-19 | 2013-07-19 | Drive circuit of motor soft starter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203352509U true CN203352509U (en) | 2013-12-18 |
Family
ID=49752356
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201320433784 Expired - Lifetime CN203352509U (en) | 2013-07-19 | 2013-07-19 | Drive circuit of motor soft starter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203352509U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105356869A (en) * | 2015-11-25 | 2016-02-24 | 天津航空机电有限公司 | Power driving circuit |
| CN108183634A (en) * | 2018-01-19 | 2018-06-19 | 浙江正泰电器股份有限公司 | Soft starter with by-pass switch error protection |
| CN108322098A (en) * | 2018-01-19 | 2018-07-24 | 浙江正泰电器股份有限公司 | Soft starter with control machines abnormal protection |
| CN114124054A (en) * | 2021-11-19 | 2022-03-01 | 广东福德电子有限公司 | Reliable trigger circuit of series thyristor |
-
2013
- 2013-07-19 CN CN 201320433784 patent/CN203352509U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105356869A (en) * | 2015-11-25 | 2016-02-24 | 天津航空机电有限公司 | Power driving circuit |
| CN108183634A (en) * | 2018-01-19 | 2018-06-19 | 浙江正泰电器股份有限公司 | Soft starter with by-pass switch error protection |
| CN108322098A (en) * | 2018-01-19 | 2018-07-24 | 浙江正泰电器股份有限公司 | Soft starter with control machines abnormal protection |
| CN108183634B (en) * | 2018-01-19 | 2024-04-19 | 浙江正泰电器股份有限公司 | Soft starter with bypass switch fault protection |
| CN114124054A (en) * | 2021-11-19 | 2022-03-01 | 广东福德电子有限公司 | Reliable trigger circuit of series thyristor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104979796B (en) | A kind of precharge type high speed d-c circuit breaker and its control method | |
| EP3131166B1 (en) | Passive high-voltage direct-current circuit breaker and implementation method therefor | |
| CN103219698B (en) | Mixing type direct-current breaker | |
| CN103269166B (en) | There is the converter of precharge defencive function | |
| CN105609344A (en) | Hybrid DC current breaker topological structure | |
| CN203352509U (en) | Drive circuit of motor soft starter | |
| CN204119020U (en) | A kind of PFC protective circuit and air conditioner | |
| CN103646805B (en) | A kind of direct-current breaker topology | |
| CN106024497B (en) | Auxiliary circuit for high-short-circuit turn-off direct-current circuit breaker and control method thereof | |
| CN103956892A (en) | Quick soft start circuit for three-phase voltage PWM rectifier and control method thereof | |
| CN102638024B (en) | Interruption line protector | |
| CN205450668U (en) | Controllable shutoff GTO intelligence arc extinction type one -way conducting device | |
| CN103972871B (en) | Direct-current feeder non-arc switch with low power consumption and overcurrent and overvoltage protection function and method for implementing direct-current feeder non-arc switch | |
| CN204349431U (en) | A kind of overpressure absorbing circuit for permanent magnet DC motor | |
| CN104882877A (en) | High voltage direct current breaker | |
| CN203261255U (en) | Traction converter and electric locomotive | |
| CN104555764B (en) | Rotary braking system and tower crane control system | |
| CN201323541Y (en) | Control circuit for positive and negative switching of small-power alternating-current motor | |
| CN203645584U (en) | Positive-negative rotating control circuit of three-phase AC motor | |
| CN205160036U (en) | High -speed direct current breaker of chargeable type in advance | |
| CN104079280B (en) | A kind of solid-state relay of high withstand voltage | |
| CN103248349A (en) | Novel electronic alternating-current contactor | |
| CN203261305U (en) | Novel electronic type alternating-current contactor | |
| CN203984385U (en) | A kind of high withstand voltage solid-state relay | |
| CN204633663U (en) | A kind of three phase alternating current motor positive and reverse rotation control circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20131218 |
|
| CX01 | Expiry of patent term |