CN87203993U - Withstanding ac voltage testing instrument for capacitor - Google Patents

Abstract

The utility model relates to a withstanding AC voltage testing instrument for a capacitor, which can overcome shortages that the existing withstanding voltage testing instruments for a capacitor are mostly direct current withstanding voltage test, and the existing withstanding voltage testing instruments for a capacitor can not test the AC withstanding voltage value of the capacitor influenced by heat breakdown factor in AC operating condition. The withstanding AC voltage testing instrument for a capacitor can apply the principle of RLC series resonance. The utility model has the advantages of simple structure, convenient operation, and accurate test. As a consequence, the utility model can enhance withstanding voltage testing means to the capacitor and is favorable for improving the quality of the capacitor.

Description

Withstanding AC voltage testing instrument for capacitor

The utility model relates to electronic instrument, especially about the instrument of capacitor ac voltage withstanding test aspect.

At present, most of capacitor voltage-withstand tests all adopt the DC break down voltage tester, these DC break down voltage testers are mainly used in the capacitor that exchanges occasion work for some, for example: the capacitor of AC motor, because the actual condition of test condition and capacitor has certain difference, the factor of some thermal breakdowns can't be measured by the DC break down voltage tester; Also there is the method for using pressure regulator to add step-up transformer to come the ac voltage withstanding of test capacitors, the power of the employed equipment of this method and the capacity of measured capacitance device have much relations, when generally the capacity of measured capacitance device is greater than 40 μ F, the required pressure regulator and the power of step-up transformer will reach several kilovolt-amperes, bulky, cost an arm and a leg, and use inconvenience, therefore, in fact this method is seldom used by people.

The purpose of this utility model is just in order to solve the above-mentioned deficiency of prior art, provide a kind of can with capacitor at the condition basically identical of AC Condition, can adapt to the capacitor testing of larger capacity scope and the ac voltage withstanding tester that volume is little, price is low, easy to use.Thereby strengthened voltage-withstand test means, helped improving the quality of capacitor, for the use and the production of capacitor brings convenience to capacitor.

Key of the present utility model is: the measured capacitance device formations-RLC series resonance tank circuit of connect with test inductance, test resistance with the voltage indicating gauge, is parallel to the output terminal of pressure regulator after controlling the contact connection.Utilize resonance principle, make measured capacitance device two ends obtain Q pressure regulator output voltage doubly; In order to be fit to the capacitor testing of different capabilities, aforesaid RLC resonant groove path can design a plurality of RL groups of being made up of a plurality of test resistance, test inductance two two-phase strings, and in the serial connection position of measured capacitance device, it is in parallel with it to design a plurality of test capacitors, by the waver that a multitool is thrown more,, press the different capabilities of measured capacitance device with these RL group and test capacitors, carry out various combination, produce the different RLC serial resonant tank circuits; The control contact that is provided with for the application time of controlling test voltage can be the switch by manual control, also can be one to have the relay of electronics time delay circuit control, and can also be both combinations.

Explanation below in conjunction with to accompanying drawing 1, accompanying drawing 2 is further elaborated principle of the present utility model and embodiment.

Accompanying drawing 1 is a ultimate principle diagrammatic sketch of the present utility model.Among the figure, TY is a pressure regulator, and its input end is communicated with working power, an output terminal alternating voltage Table V in parallel ₁, in order to the output voltage of indication pressure regulator TY, output terminal is through one pair of control contact CJ-1, CJ-2 and connect one by test resistance R _S, the test inductance L _SAnd measured capacitance device C _XThe RLC series resonance tank circuit of series connection is at measured capacitance device C _XThe serial connection position, an alternating voltage Table V also in parallel with it ₂, in order to monitor measured capacitance device C _XThe test voltage at two ends.

When control contact CJ-1, CJ-2 were closed, pressure regulator TY output voltage was voltage table V ₁Value, put on RLC tank circuit two ends.If the natural frequency of the RLC tank circuit is f ₀Just in time equal the cycle f of working power, RLC tank circuit resonance then, and get by the serial resonant principle:

Z _RLC＝ $\sqrt{R{}^2{}_S\mathrm{+(X}{}_{\mathrm{LS}}\mathrm{-X}{}_{\mathrm{CX}}){}^2}$

＝R _S－－－－－（1）

V _LS＝IX _LS－－－－－（2）

V _CX＝IX _CX－－－－－（3）

V ₁＝IZ _RLC＝IR _S－－－－－－（4）

(V _LS)/(V ₁) ＝ (X _LS)/(Rs) ＝ (2πfoLs)/(Rs) －－－－－（5）

$\frac{V_{\mathrm{<figure-callout\; id="1"\; label="CX\; V"\; filenames="87203993\_DRIMG1.png,87203993\_DRIMG2.png"\; state="\{\{state\}\}">C\; X</figure-callout>}}}{V_{}}=\frac{X_{\mathrm{C\; X}}}{R_S}=\frac{\frac{1}{{\mathrm{2\; \pi \; f}}_o\mathrm{C\; x}}}{R_S}\mathrm{－－－－－（6）}$

In the formula:

Z _RLCThe resulting impedance of the RLC tank circuit;

XL _SThe test inductance L _SInduction reactance;

X _CXMeasured capacitance device C _XCapacitive reactance;

V _LSThe test inductance L _SThe voltage at two ends;

VC _XMeasured capacitance device C _XThe voltage at two ends;

I RLC mesh current.

By (5), (6) two formulas as seen, as long as 2 π foLs＞＞R _SPerhaps 1/ (2 π foCx)＞＞R _SIn the time of Q times, the test inductance L _SOr measured capacitance C _XThe voltage at two ends will be voltage table V than the output voltage of pressure regulator TY ₁Value exceeds Q doubly, so in circuit design, suitably select test resistance R _S, just can obtain satisfied test voltage V _CXBe voltage table V ₂Indicated value.

Accompanying drawing 2 is the electrical schematic diagrams of " P8812 II---1 type ac voltage withstanding tester ", can be used as a preferred embodiment of the present utility model.The full test magnitude of voltage of this instrument is 1200V, and the capacity scope of application of measured capacitance is 0～40 μ F, and has multiple functions such as the indication of puncture, automatic/manual fixed time test and duty indication.

Fig. 2 divides upper and lower two parts, and top is the voltage-withstand test part, and the bottom is the test duration control section.

The voltage-withstand test part:

F ₁, F ₂Be fusible link, circuit is shielded.

K ₁It is complete machine working power switch.

K ₂Be that one or three cuttves six are thrown waver, it is with test resistance R _S1, R _S2, the test inductance L _S1, L _S2, testing capacitor C _S1, C _S2By measured capacitance device C _XDifferent capabilities, form a plurality of RLC serial resonant tank circuits.

R ₁, R ₂It is current-limiting resistance.

N is a neon lamp, in order to indication measured capacitance device C _XBreakdown conditions, as measured capacitance device C _XDuring puncture, this lamp extinguishes.

R ₃Be discharge resistance, one of it and pilot relay CJ often closes contact CJ-3 polyphone, is attempted by measured capacitance device C _XTwo ends after test finishes, provide measured capacitance device C _XA discharge loop that discharges electric energy.

A ₁Be an alternating current ammeter, in order to monitoring measured capacitance device C _XMeasuring current.

The principle of work of voltage-withstand test part is as follows: according to measured capacitance device C _XCapacity, by waver K ₂Select a suitable RLC series combination, closed power switch K ₁, drive controlling relay CJ makes its normally opened contact CJ-1, CJ-2 closure, often closes contact CJ-3 and disconnects, and regulate the output of pressure regulator TY then and press, and the monitor voltage Table V ₂Indicated value, until the regulation withstand voltage desired value, if measured capacitance device C _XNot breakdown yet, then can judge this measured capacitance device C _XWithstand voltage quality meet index request; Cut off the power supply of pilot relay CJ, test voltage is eliminated immediately, and measured capacitance device C _XThe electric energy that stores through discharge resistance, when often closing the very fast release of contact CJ-3 test can take off measured capacitance device C safely _X

The test duration control section:

B is a small power transformer, and its two-way is exported one tunnel working power that control circuit is provided; Another road provides " high and low pressure " status indicator lamp XD ₁, XD ₂Working power.

D ₁～ ₄Be the whole circuit of bridge that diode is formed,

J ₁, J ₂Be the control procedure relay,

AN ₁Be mould assembly high voltage startup button.

AN ₂Be that release high pressure removes button.

K ₄It is manual time switch.

R ₉～ ₁₈Be the test duration to select resistance.

D ₆～ ₁₅Be the test duration to show light emitting diode.

K ₃Be that double-pole ten is spent waver extravagantly.

BG is a unijunction transistor, and it and other resistance, electric capacity constitute time delay circuit.

ST is an one-way SCR, as the process relay J ₂Driving circuit.

Test duration control circuit principle of work is as follows: press " high pressure " start button AN ₁, the process relay J ₁Action, its normally opened contact J ₁-2 closures are moved pilot relay CJ thereupon, and the output voltage of pressure regulator TY applies RLC serial resonant tank circuit two ends through its contact CJ-1, CJ-2; Contact CJ-4 closure has been pinned " high pressure " starting state; CJ-3 disconnects, and makes discharge loop be open circuit; The CJ-5 closure, CJ-6 disconnects, and makes pilot lamp XD ₁To transfer lamp to bright by extinguishing, and pilot lamp XD ₂Then extinguish by lamp bright transferring to, in order to whether applying of expression test voltage, i.e. " high and low pressure " state indication.This moment, time delay circuit is through contact J ₁-1 and the process relay J ₂Coil winding obtain working current, pick up counting, until the control time of selecting, unijunction transistor BG conducting, controllable silicon ST obtains evoked potential conducting thereupon, makes relay J ₂Obtain action current and start, it is moving from contact J ₂-1 is the disconnection shape, makes relay J ₁The electric current of losing the job, the contact of former adhesive all discharges recovery, and pilot relay CJ also therefore restores, and test voltage is cancelled thereupon, has finished the control of a fixed time test.In the process of fixed time test, can press " high pressure " at any time and remove button AN ₂, remove applying of time delay control procedure and test voltage.During the manual control fixed time test, earlier with selection of time waver K ₃Put the neutral position, make time delay circuit inoperative, then can be by manual time switch K ₄Come the action of pilot relay CJ, realize application time control test voltage.

Claims (3)

1, a kind of capacitor ac voltage withstanding tester contains a pressure regulator, and its input end links to each other with power supply through a power switch, and output terminal alternating voltage indicating gauge in parallel is characterized in that: measured capacitance device C _XWith the test inductance L _S, test resistance R _SSeries connection constitutes a RLC series resonance tank circuit, and contact CJ-1, CJ-2 connect through control, is parallel to the output terminal of pressure regulator TY.

2, according to the described capacitor ac voltage withstanding of claim 1 tester, it is characterized in that: the described RLC series resonance tank circuit, it tests inductance L _SAnd test resistance R _SCan be by a plurality of test inductance L _SWith a plurality of test resistance R _STwo two-phase strings are formed a plurality of RL groups, measured capacitance device C _XAt the series position place of the RLC tank circuit, can fix and connect one or more test capacitors C _S, and throw waver K by a multitool more ₂With aforesaid a plurality of RL groups and a plurality of test capacitors C _S, by measured capacitance device C _XDifferent capabilities, realize the combination of the different RLC tank circuits.

3, according to the described capacitor ac voltage withstanding of claim 1 tester, it is characterized in that: described control contact CJ-1, CJ-2, its closure and disconnection can be the switches by manual control, also can be to be realized by the relay with the control of electronics time delay circuit, can also be both combinations.

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