CN201765728U - Power source for three-phase alternating current experiment - Google Patents
Power source for three-phase alternating current experiment Download PDFInfo
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- CN201765728U CN201765728U CN2009202911812U CN200920291181U CN201765728U CN 201765728 U CN201765728 U CN 201765728U CN 2009202911812 U CN2009202911812 U CN 2009202911812U CN 200920291181 U CN200920291181 U CN 200920291181U CN 201765728 U CN201765728 U CN 201765728U
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Abstract
The utility model discloses a power source for a three-phase alternating current experiment, which comprises a sine wave oscillator, a voltage meter and a current meter, wherein the signal output terminals of the sine wave oscillator are connected with a non-phase-shift amplifier and a two-channel phase-shift amplifier respectively. A working power source is used for supplying voltage-stabilized direct-current power to all the circuits. The power source outputs a stable low-voltage three-phase alternating current, the three-phase voltages of the low-voltage three-phase alternating current are equal, and the phase differences among the three-phase voltages are 120 degrees. The common ground line is the mean line of the three-phase alternating current power source. The utility model solves the problems of the conventional three-phase alternating current experiment equipment that the three-phase voltages and the phase differences are out of balance, unstable and unsafe, the power consumption is high and the size is large. The utility model allows the user to conveniently observe the generation of electric currents in the mean line caused by the imbalance of the three-phase voltages or the phase differences. The utility model is either used as an experimental apparatus alone or combined with the common electrical and electronic practice platform. The utility model is applied to the three-phase alternating current experiment in high schools, so as to greatly improve the experimental accuracy and effect, and avoid the risk of electric shock during the experiment.
Description
Technical field
The utility model relates to a kind of experimental provision, refers in particular to a kind of three-phase alternating current experimental power supply.
Background technology
Domestic all types colleges and universities, three-phase alternating current experiment is one of the electrotechnical, electronic experimental project that must do of science students, and the existing experimental provision that is used for this experiment is nothing more than two big classes are arranged: a class is to assemble experimental circuit with discrete instrument fully by the student, another kind of is that relevant instrument and equipment are installed on the electrotechnical, electronic experiment table, and the student is just passable as long as press circuit grafting line.The experimental project (70-72 page or leaf) of paying " measurement of three-phase circuit voltage, electric current " in tame colleges and universities' experimental teaching material " electrotechnical, electronic is put into practice study course " of just writing that for example in June, 2003, Chemical Industry Press published is exactly directly to adopt the three-phase alternating current civil power to experimentize.But the three-phase alternating current that adopts in the above-mentioned two big class laboratory facilities all is directly to take from the three-phase alternating current civil power, and for the three-phase alternating current civil power, because (threephase load all is at random at each to the uncertainty of whole network system threephase load constantly, cause the threephase load imbalance) and the electric power system internal resistance non-vanishing, cause three-phase electricity uneven and unstable, this shows that three-phase voltage is unequal and unstable, and the phase differential of three-phase voltage neither 120 degree or unstable.These errors that all can cause experimental result are very big, even make teachers and students be difficult to tolerance.Moreover, the three-phase alternating current line voltage is very high, experimental apparatus and Personal Safety are low, normal accidents such as instrument burns out take place, the time have the electric shock phenomenon take place (though usually owing to insulate, the serious electric shock accidents of generation not too easily, but each experiment still makes teachers and students worry very much), and power consumption is many, and the total power consumption of every cover experimental apparatus light modulation bubble just reaches one or two hectowatts, the bulky heaviness of experimental provision.In addition, can't demonstrate the variation that causes current in middle wire when three-phase alternating-current supply becomes imbalance by equilibrium state.
Summary of the invention
The purpose of this utility model provides a kind of voltage magnitude of three-phase alternating-current supply and phase differential is all adjustable, that output is stable, volume is little, in light weight, the three-phase alternating current experimental power supply of safety electricity-saving, when it can be observed three-phase voltage amplitude or phase differential easily and becomes imbalance by balance, the variation of caused current in middle wire.
To achieve these goals, the utility model comprises the voltage table of the phase voltage that monitors three-phase alternating current, survey the reometer of current in middle wire, the working power that the step-down of single-phase 220V electric main, rectification, filtering, voltage stabilizing are formed, for providing galvanic current, subsequent conditioning circuit presses, also have a pure oscillator, the output terminal of pure oscillator links to each other with the input end of non-phase shift amplifirer, and the output terminal of pure oscillator also links to each other with the input end of two phase shift amplifirers.Working power links to each other with the power input of pure oscillator, non-phase shift amplifirer, two phase shift amplifirers respectively.The output terminal of voltage table and amplifirer is in parallel.The ground wire of working power is also as the center line of three-phase alternating current power supply.
Be to guarantee the output voltage stabilization of pure oscillator, the not influence of level load variations subsequently is an emitter-follower in the final stage of pure oscillator.
Two-way phase shift amplifirer all is to be formed by connecting by amplitude regulating circuit, phase-shift circuit, power amplifier.Like this, three road different sinusoidal acs of output voltage phase place have just been formed between non-phase shift amplifirer, the two-way phase shift amplifirer three, and, just can access all three-phase alternating currents of satisfactory balance of voltage and phase differential easily by regulating amplitude regulating circuit and phase-shift circuit separately.
One of phase-shift circuit constitutes two-stage RC phase-shifting unit by two electric capacity and two variable resistors, can produce the output voltages of leading 120 degree stable, that waveform is good.Normally closed switch in parallel is connected with amplitude regulating circuit after damping resistance and the Live switch parallel connection on an electric capacity of phase-shift circuit.Normally closed switch and Live switch are mechanical linkage.So just can be by controlling the phase place that this mechanical linkage switch comes a phase power supply of independent easily control three-phase alternating current, the change phase place does not have influence to voltage.Another of phase-shift circuit connected to form by single-stage RC phase-shifting unit and inverting amplifier, can produce the output voltage of the hysteresis stable, that waveform is good 120 degree.
To the requirement of high voltage, also the three-phase supply transformer is linked to each other with the output terminal of three-phase alternating current is removable when surveying electric power in order to satisfy common electric power meter.
Because after the utility model is used single-phase AC 220V civil power step-down rectifier filtering voltage regulation, constitute working power, offer sine-wave oscillator, non-phase shift amplifirer, two-way phase shift amplifirer respectively, make it to produce the three-phase alternating current that three road voltages and phase differential all can be set up, and have center line, this has just constituted desirable, real three-phase alternating-current supply balance, stable, overcome existing three-phase alternating current experimental power supply and directly taken from the uneven and unstable experimental error of bringing of three-phase alternating current that 380V three-phase alternating current civil power brings, improved experiment effect greatly.Moreover, because the utility model adopts 220 single-phase AC mains-supplied to produce the low-voltage three-phase AC electricity of balance and stability, the security of experiment improves greatly, does not have the danger of getting an electric shock.Because the three-phase electricity voltage of output is very low, experimental apparatus and experiment equipment are not fragile yet, and the experiment power consumption also reduces greatly, meets the economize on electricity principle of the world today, and also can do the three-phase alternating current experiment in the place of no three-phase alternating-current supply, expand the scope of application of product.Live switch in parallel on the resistance of amplitude regulating circuit, and on the electric capacity of phase-shift circuit normally closed switch in parallel, and make this two switch mechanical linkages, just can observe the current in middle wire that the phase differential imbalance of the voltage magnitude imbalance of three-phase alternating current or three-phase alternating current caused respectively easily and lead to a phenomenon, can deepen the understanding of student three-phase electricity.Link to each other with the output terminal of three-phase alternating current is removable with the three-phase supply transformer, can select during demand to boost, made things convenient for use according to experiment with it.Phase-shift circuit is connected to form by single-stage phase-shifting unit and inverting amplifier, has solved to carry out with multistage Resistor-Capacitor Unit that signal that super wide phase shift brings is extremely decayed and the defective of waveform difference.Volume of the present utility model, weight, cost all are lower than the product of prior art, the cost performance height.
Description of drawings
Fig. 1 is the circuit theory diagrams of first embodiment of the present utility model.
Fig. 2 is the circuit diagram of the utility model working power.
Fig. 3 is the circuit diagram of the phase in the utility model threephase load.
Fig. 4 is the simplified electrical circuit diagram of first embodiment of the present utility model.
Fig. 5 is the circuit diagram of second embodiment of the present utility model.
Fig. 6 is the circuit diagram that univoltage table of the present utility model is surveyed three phase voltages.
Fig. 7 is the circuit diagram of band step-up transformer of the present utility model.
Embodiment
In Fig. 1, working power 1 can be converted into electric main 220V the low-voltage DC of voltage stabilizing, and its internal circuit adopts step-down of the prior art, rectification, filtering, mu balanced circuit to constitute, and series connection or switching power supply all can.Its positive polarity is+E that it provides voltage stabilizing+12V direct current for pure oscillator 2, non-phase shift amplifirer, two-way phase shift amplifirer.Pure oscillator 2 can adopt Wen's bridge pure oscillator of the prior art, also can adopt the pure oscillator of other types, requires good output waveform, output frequency and voltage stable.The resistance R 13 of Wen's bridge pure oscillator, capacitor C 7 and C9, resistance R 17 are formed the frequency selection network of control oscillation frequency, triode T2 and emitter degeneration resistance R 18, collector resistance R16, base biasing resistor R15 constitute the first order and amplify, resistance R 14, capacitor C 10 constitute the filtering circuit of this grade amplification, and capacitor C 8, C11 are input, output coupling capacitor.Triode T3 and emitter degeneration resistance R 20, collector resistance R22, base biasing resistor R19 and R21 constitute the second level and amplify, and resistance R 23, capacitor C 12 constitute the filtering circuit of this grade amplification.Semifixed resistor R24 is big loop negative feedback resistor.Capacitor C 13 is output coupling capacitors.Resistance R 25 and capacitor C 14, C15 constitute low-pass filter, can reduce noise and prevent high-frequency self-excitation.Triode T4 and emitter degeneration resistance R 28, base biasing resistor R26 constitute emitter-follower, and resistance R 27, capacitor C 17 constitute the filtering circuit of emitter-follower.Input, output coupling capacitor are respectively C16, C18.Capacitor C 19 plays the High frequency filter effect, further prevents self-excitation.In order to guarantee the stable of oscillation frequency, capacitor C 7 and C9 will be with the good electric capacity of temperature stability (such as electric capacity of the dacron etc.).
Non-phase shift amplifirer is made of the resistance R 1 and the potentiometer R2 of power amplifier 3 and amplitude regulating circuit, and for the minute adjustment output voltage, the potentiometer R2 that regulates output voltage amplitude is best with multiturn potentiometer.All potentiometers described later all advise adopting multiturn potentiometer, the normal multiturn potentiometer of regulating that should select large volume for use, the seldom available small-sized multiturn potentiometer of Tiao Jieing.Power or high-power audio power amplifier integrate circuit constituted during its intermediate power amplifier 3 can be used, and can simplify circuit like this and improve performance.
First via phase shift amplifirer is by resistance R 3, the R of its amplitude regulating circuit
K, R4, phase-shift circuit capacitor C 1, C2 and potentiometer R5, R6 (also promptly this phase-shift circuit is made of the RC phase-shift circuit that electric capacity and variable resistor constitute) and power amplifier 4 constitute.In order to demonstrate current in middle wire or the neutral displacement phenomenon that three-phase voltage or phase differential imbalance cause, also in resistance R
KWith a normal open in parallel respectively and normally closed switch on the capacitor C 1, and these two switch mechanical linkages (the present invention claims the mechanical linkage switch), such as just realizing this function with the two position of common double-pole Button toggle switch; Also want a pushbutton switch independently in parallel on the resistance R 3, change this voltage of exporting mutually and loose one's grip back recovery voltage balance automatically with independent.When production debugging, K switch 1, K2, K3 should be at states (K1, K2 are disconnected, and K3 is logical) as shown in Figure 1.Insert X, the Y input end of dual trace oscilloscope respectively at the output terminal B of the output terminals A of non-phase shift amplifirer and this road phase shift amplifirer, at first regulate resistance R 5, R6, make leading 120 degree of output terminal B specific output end A voltage-phase, regulate R2, R4 again, make output terminal B equate (such as 2.2V) with output terminals A voltage, and then stir the mechanical linkage switch to the position (should on instrument panel, put on the phase differential nonequilibrium state to this state) that K2 connects, K3 disconnects, regulate semifixed resistor R
K(should with small-sized multi-turn semifixed resistor) makes output terminal B equate once more with output terminals A voltage.At this moment, non-phase shift amplifirer and first via phase shift amplifirer have just mixed up.
The amplitude regulating circuit of the second tunnel phase shift amplifirer is made of resistance R 7, potentiometer R8.The prime phase-shift circuit is made of the single-stage RC phase-shifting unit of leading 60 degree of voltage capacitor C 3, potentiometer R9.Triode T1, negative feedback resistor R10, bias fine-tuning resistance R 11, collector resistance R12, filter capacitor C5, filter resistance R
0, input and output coupling capacitance C4 and C6, high-frequency filter capacitor C
0Constitute inverting amplifier, it can make output voltage 180 degree that lag behind, and after the single-stage RC phase-shifting unit combination of leading 60 degree of voltage that are made of capacitor C 3, potentiometer R9 of its front, total phase shift is a hysteresis-180+60=-120 degree.Again this voltage signal being sent into power amplifier 5, just is the voltage of 120 degree from output terminal C lag output output terminals A.So, output voltage phase differential mutual deviation 120 degree of output terminals A, B, C, the center line of the ground wire of working power as three-phase alternating-current supply, the three-phase alternating-current supply of three-phase four-wire system has just formed again.The method of regulating the second tunnel phase shift amplifirer is: the X, the Y input end that insert earlier dual trace oscilloscope at the output terminal C of the output terminals A of non-phase shift amplifirer and the second tunnel phase shift amplifirer respectively, at first regulate resistance R 9, make output terminal C specific output end A voltage-phase hysteresis 120 degree, regulate R8 again, make output terminal C equate (such as 2.2V) with output terminals A voltage.At this moment, the second tunnel phase shift amplifirer has just mixed up.
Above-mentioned two-way phase shift amplifirer also can be regulated R4 or R8 earlier when regulating, make two output voltage amplitude and output terminals A about equally, regulates phase differential separately again, so just need not regulate oscillographic vertical size significantly and just can carry out the comparison of phase differential.In addition, amplitude can change during the control phase difference, and suggestion amplitude and phase differential are alternately regulated.
Threephase load Z
A, Z
B, Z
CEach mutually all can make circuit structure shown in Figure 3, and to be installed in each element on a small plastic box or the plastics fixed mount, also to draw two electrode X, Y.Pull-up resistor R
LAvailable resistant to elevated temperatures 0.5W or above metalfilmresistor are after light emitting diode D5, the D6 parallel connected in reverse phase, with current-limiting resistance R
XSeries connection constitutes luminous demonstration, can make the student that the variation of every phase voltage under the various experimental states is had individual understanding intuitively.Light emitting diode D5, D6 will be with the common light emitting diode about forward voltage 1.8V, to guarantee that low voltage also can luminously show.Also can remove a light emitting diode, but current-limiting resistance R in the case
XThan pull-up resistor R
LBig more than 10 times, can avoid the experimental precision due to the total resistance value of serious this phase load of non-linear effects of single light emitting diode to reduce like this.Because in three-phase alternating current experiment, balanced load (i.e. three load Z are arranged
A, Z
B, Z
CResistance or impedance are equal fully) and the experiment content of two kinds of situations of asymmetric load, so can make three identical loads, adding a load that resistance is different again, the student selects during for experiment.The phase voltage of this instrument is preferably transferred at 2.2V, the corresponding 3.8V of this line-transect voltage, with line voltage be in number similar be little 100 times, this helps deepening the student to phase voltage and line voltage
The understanding of relation doubly.Certainly, threephase load Z
A, Z
B, Z
CEach mutually also available common on the market electric torch 2.2V or 3.8V miniature bulb, advantage is the brightness height, but power consumption is more than aforesaid, the life-span is short, and resistance equates that not necessarily differing obtains well-balanced threephase load surely.
The student wants the three-phase four-wire system three-phase supply when doing threephase load and make the experiment content of star connection, need a center line.Because the output of three power amplifiers 3,4,5 is common ground, so ground wire is exactly center line O, the alternating current Table A of can on center line O, connecting
O, can observe and measure output of three-phase alternating-current supply balance and balanced load during experiment and not have the experiment content that current in middle wire, the uneven output of three-phase alternating-current supply or asymmetric load produce current in middle wire, certainly, the alternating current Table A
OAlso can be external by the student.Three alternating voltage Table V
A, V
B, V
CBe three phase voltages that are used for monitoring or measure three-phase alternating-current supply, the voltage that disconnects in the threephase load of back at center line will connect A.C. voltmeter in addition, thus the time both are different.Three alternating voltage Table V
A, V
B, V
CAlso can cooperate a switch K by a shared voltage table V
BSurvey three phase voltages respectively, as shown in Figure 6, switch K wherein
BBe a waver, A, B, C are the output terminal of three power amplifiers.Threephase load Z
A, Z
B, Z
CWhen making delta connection, also want external AC to press table, because will survey the line voltage of three-phase alternating-current supply and the phase voltage on every phase load this moment.Also an A.C. voltmeter about range 5V can be installed on the shell of this product again, on this table, draw two leads and connect the test test pencil respectively, cooperate the alternating current Table A again
O(this moment, this reometer just can not be with in the fixing access way access circuitry, and the structure that will take two wiring of reometer and entire circuit socket connection) just can experimentize by any external ammeter.
Fig. 2 is the working power 1 that a kind of tandem stabilized voltage supply that the utility model is used constitutes.Transformer B
YSmall power transformer about available 10W is about secondary voltage 18V.Diode D1, D2, D3, D4 constitute bridge rectifier.IC1 is a three-terminal voltage-stabilizing integrated package 7812, its input, output, hold and be respectively a, c, b, capacitor C 26, C28 are low frequency filtering electric capacity, capacitor C 27, C29 are high-frequency filter capacitor.Output terminal+E is exportable+and DC voltage and the voltage of 12V is very stable.Working power 1 usefulness dc switching power supply on the market also can.
Fig. 4 is the reduced graph of present embodiment Fig. 1, just 2 of the pure oscillator of Fig. 1 is made into block diagram, and the power amplifier 5 of Fig. 1 is also made into the form of block diagram, and remaining two figure is identical, no longer narration.
Fig. 5 is the circuit diagram of second embodiment of the present utility model, overwhelming majority circuit is identical with first embodiment, difference only is that the phase-shift circuit of the second tunnel phase shift amplifirer is to be combined by four RC phase-shifting units, and after four RC phase-shifting units combinations, too big to signal attenuation, also must increase the in-phase amplifier 6 of a high-amplification-factor thereafter.In-phase amplifier 6 can combine with common two-stage grounded emitter amplifier, and it is anti-phase that the first order is amplified, and the second level is amplified anti-phase again, and combined result is last amplify output and input signal homophase input end.
Fig. 7 is the circuit diagram of band step-up transformer of the present utility model.Its purpose is to allow the utility model can cooperate the existing electric power meter commonly used in laboratory to survey the electric power of threephase load with two meter technique.Because the output voltage of aforementioned circuit is at the order of magnitude of several volts, the common electrical power meter be can't reading (certainly, go ammeter factory customized or newly to purchase the power meter of several volts of voltage best).In Fig. 7, three-phase supply transformer B
HCan be formed by connecting by three identical single-phase step-up transformers, also " day " word iron core of the employing of available prior art is made a three-phase supply transformer, its transformation ratio (or primary and secondary umber of turn ratio) is about 1: 40, just 3.8V voltage can be elevated to volt more than 100, at this moment common common electrical power meter is just available.So, all experimental projects of three-phase alternating current can have been done.Three-phase supply transformer B among Fig. 7
HThe terminal A of elementary winding (or claim three-phase supply transformer low pressure winding)
1, B
1, C
1Be end of the same name, respectively with three output terminals A of amplifirer, B, C are removable is connected, three terminals connect together and meet center line O in addition
1Secondary A
2, B
2, C
2Be end of the same name, three terminals connect together and are connected into center line O in addition
2, like this at A
2, B
2, C
2Exportable more than the 100 line voltages that lie prostrate between three output terminals.Though volt more than 100, since little to isolation of the earth electricity and the high electric current of the internal resistance of source, not entail dangers to personal safety.Correspondingly Ci Shi threephase load will increase resistance value to more than the 10K, and light emitting diode is also wanted corresponding raising resistance.
Three-phase supply transformer B
HShould be with other parts are removable and be connected, so that whether autonomous selection of user experimentizes with this transformer.
The concrete parameter of each components and parts of the present utility model following (front said just do not repeated) at this:
Triode T1 is that low frequency amplifies low-power transistor C945, and triode T2, T3, T4 amplify low-power transistor C9013 for low frequency entirely.Diode D1, D2, D3, D4 are 1N4007 entirely.Resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, R30, R31, R32, R33, R34, R35, R36, R
K, R
0Be respectively 3.9,1,0.1,1,50,50,20,1,10,0.33,1000,6.3,16,1,500,1,16,0.62,1.5,0.039,15,2,1,2,50,200,0.36,1,1,0.004,0.18,0.005,50,50,50,50,5,0.5 kilohms (K Ω).But above-mentioned resistance only is meant its maximum nominal value concerning potentiometer, sees below with reference to regulated value and states.The metalfilmresistor of the complete available resistance 10-80 Ω of pull-up resistor RL, corresponding current-limiting resistance R
XConventional, electric-resistance with 300-1300 Ω.Capacitor C 1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C30, C31, C32, C33, C
0Be respectively 0.01,0.01,0.2,10,100,10,0.05,10,0.05,100,10,100,10,0.01,0.01,10,100,10,0.01,4.7,0.001,220,470,0.1,470,1000,0.1,1000,0.01,0.01,0.01,0.01,0.01,0.01 microfarad (μ f), the withstand voltage of electrochemical capacitor C26 will be equal to or greater than 25V, the complete available withstand voltage 16V's of remaining electrochemical capacitor.Three-terminal voltage-stabilizing integrated package 7812 and three power amplifier integrate circuit TDA2030A want radiation fin.Three alternating voltage Table V
A, V
B, V
CAnd alternating current Table A
OAvailable pointer ammeter to reduce cost, improves reliability of products.
I have made a model machine according to the technical solution of the utility model, and am very successful.It is as follows partly to survey statement parameter below: the oscillation frequency of pure oscillator is 195HZ, and wherein negative feedback semifixed resistor R24 is adjusted in 1.6K.Semifixed resistor R
K, R11 is adjusted in 3.1 respectively, on the resistance of 470K.Multiturn potentiometer R5, the R6 of control phase difference, R9 are adjusted in 27,50 respectively, on the 2.6K, and amplitude of accommodation regulator potentiometer R2, R4, R8 do not influence the phase differential between the three-phase alternating voltage at all.Output three phase voltages and three line balances of voltage fine, and satisfy line voltage and phase voltage between
Relation doubly.Current in middle wire 0.00025A only when balanced load almost approaches zero.When stirring mechanical linkage K switch 2, K3 to any state, phase differential and magnitude of voltage are independent of each other.The three-phase alternating current of output is distortionless sine wave.Overall Power Consumption is less than 9W, is far smaller than the power consumption of prior art.
The first via phase shift amplifirer and the second tunnel phase shift amplifirer are collectively referred to as the phase shift amplifirer.When K switch 1 is connected, the output voltage V of first via phase shift amplifirer
BImprove (being elevated to 2.45V by original 2.2V, just in time the amplitude of analog AC line voltage rising), cause artificial three-phase voltage amplitude imbalance, can observe the phenomenon of the current in middle wire generation that causes thus; When stirring mechanical linkage K switch 2, K3, only change phase differential and magnitude of voltage is constant, cause the phase differential imbalance of artificial three-phase voltage, can observe the phenomenon that the current in middle wire that causes thus produces to the disconnected state of the logical K3 of K2.If K1 adopts pushbutton switch, can finish watching three-phase voltage amplitude imbalance after automatic cutout reset, the output of automatic recovery three-phase electricity, this is of great benefit to the understanding and the memory of three-phase alternating current electric theory to deepening the student.K switch 1, K2, K3, R
KAlso can receive the second tunnel phase shift amplifirer relevant position, similar to the former effect.K switch 1 and mechanical linkage K switch 2, K3 will be by on the guidance panel of casing, to make things convenient for control operation.
Like this, at sinusoidal wave low-voltage AC that voltage is adjustable of output terminals A output, can obtain one respectively at output terminal B and output terminal C is respectively the two-way low frequency acs of 120 degree and 240 degree (or claiming that negative 120 spend) with the output terminals A phase differential, and potentiometer R4, the R8 of the amplitude regulating circuit of the big I of output voltage by separately regulate respectively, and can be transferred to the magnitude of voltage identical with output terminals A.Because of this three road low frequency ac all is common ground, so the ground wire of working power 1 just is equivalent to the center line O of three-phase alternating-current supply.Like this, just can obtain the three-phase and four-line AC power of the real balance that phase differential equates every 120 degree, magnitude of voltage mutually from output terminals A, B, C, O.Also owing to adopt the stabilized voltage supply power supply,, be not subjected to the influence of line voltage variation and phase change in addition so this three road output voltage and phase differential are also very stable.
Three voltage table V that monitor the voltage of three-phase alternating current
A, V
B, V
C, be directly installed on the control panel on the casing, with convenient observation.Threephase load Z
A, Z
B, Z
CTo be produced on separately in the little plastic housing and and make the plug shape its two ends.Supporting with it socket also should be fixed on the casing, but the socket of every phase load correspondence can not directly be linked to be wye connection, the socket that each contact wants the several inner leads of polygamy to link to each other, mix some plug wires outward again, so that the student independently is connected into star-like when doing experiment or delta connection and measure with ammeter.
Casing of the present utility model can be made arbitrary shape, as: can be rectangular, also can make panel type very intuitively, draw circuit structure diagram and line graph from panel again, mix corresponding jack and plug cord again, can inspire student's innovation and creation consciousness,, be different from existing three-phase alternating current production method fully because of this is the circuit of the knowledge composition of different field such as comprehensive electrotechnics, electronic circuit.The utility model can also be combined on the existing common large-scale electrotechnical, electronic experiment table, significantly improve its performance and experiment effect.
The utility model can be done many variations, such as: two-stage RC phase-shifting unit is made into three grades of RC phase-shifting units, but the parameter of RC element to change at this moment.The also available step-up transformer of the inverting amplifier of the second tunnel phase shift amplifirer is connected into anti-phase connection and replaces, but this moment, cost improved, and volume increases.
Claims (6)
1. three-phase alternating current experimental power supply, comprise a working power, it is characterized in that pure oscillator in addition, the output terminal of pure oscillator links to each other with the input end of non-phase shift amplifirer, the output terminal of pure oscillator also links to each other with the input end of two phase shift amplifirers, working power links to each other with the power input of pure oscillator, non-phase shift amplifirer, two phase shift amplifirers respectively, the output terminal of voltage table and amplifirer is in parallel, and the ground wire of working power also is the center line of three-phase alternating current power supply.
2. by the described three-phase alternating current experimental power supply of claim 1, it is characterized in that the phase shift amplifirer is formed by connecting by amplitude regulating circuit, phase-shift circuit, power amplifier.
3. by the described three-phase alternating current experimental power supply of claim 2, a RC phase-shift circuit that is made of electric capacity and variable resistor that it is characterized in that phase-shift circuit is formed, normally closed switch in parallel on an electric capacity of phase-shift circuit, connect with amplitude regulating circuit after damping resistance and the Live switch parallel connection, normally closed switch and Live switch are the mechanical linkage switches of one.
4. by the described three-phase alternating current experimental power supply of claim 2, another that it is characterized in that phase-shift circuit connected to form by single-stage RC phase-shifting unit and inverting amplifier.
5. by the described three-phase alternating current experimental power supply of claim 1, it is characterized in that the output terminal of amplifirer and the low pressure winding of three-phase supply transformer join.
6. by the described three-phase alternating current experimental power supply of claim 1, the final stage that it is characterized in that pure oscillator is an emitter-follower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202911812U CN201765728U (en) | 2009-12-30 | 2009-12-30 | Power source for three-phase alternating current experiment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202911812U CN201765728U (en) | 2009-12-30 | 2009-12-30 | Power source for three-phase alternating current experiment |
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| CN201765728U true CN201765728U (en) | 2011-03-16 |
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| CN2009202911812U Expired - Fee Related CN201765728U (en) | 2009-12-30 | 2009-12-30 | Power source for three-phase alternating current experiment |
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| Country | Link |
|---|---|
| CN (1) | CN201765728U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103368610A (en) * | 2013-08-01 | 2013-10-23 | 国家电网公司 | Intelligent distribution room networking instrument for power system |
| CN104638881A (en) * | 2013-11-12 | 2015-05-20 | 哈尔滨商业大学 | Three-phase power supply |
| CN108492658A (en) * | 2018-03-30 | 2018-09-04 | 国网四川省电力公司德阳供电公司 | Portable electric meter wiring emulating instrument |
| CN110568235A (en) * | 2019-09-09 | 2019-12-13 | 广东安朴电力技术有限公司 | Intelligent high-voltage test power supply system and control method |
-
2009
- 2009-12-30 CN CN2009202911812U patent/CN201765728U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103368610A (en) * | 2013-08-01 | 2013-10-23 | 国家电网公司 | Intelligent distribution room networking instrument for power system |
| CN104638881A (en) * | 2013-11-12 | 2015-05-20 | 哈尔滨商业大学 | Three-phase power supply |
| CN104638881B (en) * | 2013-11-12 | 2017-08-25 | 哈尔滨商业大学 | A kind of three phase mains |
| CN108492658A (en) * | 2018-03-30 | 2018-09-04 | 国网四川省电力公司德阳供电公司 | Portable electric meter wiring emulating instrument |
| CN108492658B (en) * | 2018-03-30 | 2019-09-17 | 国网四川省电力公司德阳供电公司 | Portable electric meter wiring emulating instrument |
| CN110568235A (en) * | 2019-09-09 | 2019-12-13 | 广东安朴电力技术有限公司 | Intelligent high-voltage test power supply system and control method |
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Granted publication date: 20110316 Termination date: 20111230 |