CN2051356U

CN2051356U - Electronic megger

Info

Publication number: CN2051356U
Application number: CN 89205296
Authority: CN
Inventors: 孙平权; 孟浩渊
Original assignee: Staff & Workers Technology Market Nanjing City
Current assignee: Staff & Workers Technology Market Nanjing City
Priority date: 1989-08-09
Filing date: 1989-08-09
Publication date: 1990-01-17

Abstract

The utility model mode discloses an alternating-current/direct-current electronic megger, comprising a casing, a rectifying circuit, a high-frequency oscillating circuit, a voltage-boosting voltage-doubling rectifying circuit and a measuring circuit. The head, of the megger of the utility model, which is in the measuring circuit is arranged at the facade of the casing; a plug jack for a measure pen is arranged on the casing for the convenience of the connection between the measure pen and the binding posts in the megger of the utility model; the voltage tuning knob can regulate the direct current high voltage in the megger of the utility model conveniently, and thus the alternating-current/direct-current electronic megger can test insulating workpieces with different pressure-proof value.

Description

Electronic megger

The utility model relates to the electronics megohmmeter of test Insulation Material resistance value, and the AC/DC electronics megohmmeter of the different withstand voltage insulating material resistance values of particularly a kind of energy test belongs to the electrical measurement field.

Megohmmeter in the market, its principle are by the hand generator generating, and the electric current difference that produces by two coils reflects what measured workpiece insulated, and should select the megohmmeter (megger) of different size for use according to the withstand voltage situation of tested insulation workpiece.For example measured workpiece has only the withstand voltage insulation of 500V, just can only use the 500V megger, and the megger of other specification all can not use.When measuring, will survey pen clip earlier on measured workpiece, use hand generator again, obtain measured value from gauge outfit.Because its volume is bigger, heavy and operation inconvenience has brought many difficulties just for high-altitude, field work, needs two people to operate sometimes.In electronic enterprises,, all there is not desirable testing tool as the resistance more than tens megaohms, capacity fall off situation more than a few hectovolt.

The utility model is at the problems referred to above, has designed a kind of electronic type megohmmeter, and not only volume is little, and is easy to use, and dependable performance, brought into play the characteristics of megohmmeter, has solved the test specification that multimeter can't resolve.

The utility model is finished by following manner: on the printed-wiring board (PWB) of enclosure interior, by several sections such as prior art installing rectification circuit, high-frequency oscillating circuits, the voltage doubling rectifing circuit of boosting and test circuits.Rectification circuit at first becomes 6V by power transformer with the step-down of 220V civil power, through rectifier cell it is become direct current 6V again.Rectifier cell can be the full-wave rectification of two diodes, also can be that four diodes are formed bridge rectifier, adds capacitor filtering again.Said direct supply also can provide by in enclosure interior dry cell being installed.High-frequency oscillating circuits can adopt a triode, a transformer, two electric capacity and a resistance to form 3 condenser type oscillators, and its oscillation amplitude can be controlled by trim-pot.By oscillator, low-voltage DC is become the low pressure high-frequency alternating current, the transformer in the oscillatory circuit becomes the high voltagehigh frequency alternating current with low pressure high-frequency ac electric boost simultaneously.The voltage doubling rectifing circuit of boosting is made up of a boost capacitor, two rectification and voltage multiplier diodes and a filter capacitor.The effect of the voltage doubling rectifing circuit of boosting is that the high voltagehigh frequency alternating current is become high voltage direct current.Metering circuit is made up of two resistance, a gauge outfit and two binding posts, and gauge outfit and binding post can be arranged at the front of housing.Use is surveyed pen by binding post, can easily high voltage direct current be added to place measured workpiece, and the electric current of measured workpiece can directly reflect on gauge outfit, becomes M Ω through conversion, and directly reading is on gauge outfit.

Now with embodiment the utility model is described in further detail in conjunction with the accompanying drawings.

Fig. 1 is an electronics megohmmeter electricity functional-block diagram;

Fig. 2 is an electronics megohmmeter circuit diagram;

Fig. 3 is a kind of print pattern of Fig. 2;

Fig. 4 is a kind of shell structure synoptic diagram of electronics megohmmeter;

Fig. 5 is the embodiment circuit diagram of electronics megohmmeter.

With reference to Fig. 1,1 is rectification circuit, and 2 is oscillatory circuit, and 3 are the voltage doubling rectifing circuit of boosting, and 4 is metering circuit.

With reference to Fig. 2, Fig. 3 and Fig. 5, on printed-wiring board (PWB) (5), device has transformer T ₁And bridge rectifier element D ₁-D ₄Four diodes and filter capacitor C ₁Form rectification circuit.Battery case B is in order to place dry cell.In conjunction with Fig. 2, on housing (6), be provided with electric current socket (7), when inserting the electric main attaching plug, by machine interpolation block K switch.The interior dry cell direct current normally closed contact (8) of the machine that breaks is connected alternating current contact (9).Power switch K ₁Be the complete machine power switch, connect back light emitting diode D ₇Brighten, indicate megohmmeter and entered duty, light emitting diode D ₇By the positive aperture (14) of housing (6) as pilot lamp.K switch ₁Can be arranged on the housing.Pliotron BG and capacitor C in the high frequency ₂, C ₃Resistance R ₁And transformer T ₂Primary coil form 3 condenser type high-frequency oscillating circuitss, its frequency is between 1Kc～100Kc.Low pressure high-frequency alternating current after the vibration is through transformer T ₂Secondary coil become the high voltagehigh frequency alternating current.The adjusting of trim-pot W is gone up voltage tuning knob (10) by housing (6) and is realized.Boost capacitor C ₄, rectification and voltage multiplier diode D ₅, D ₆And filter capacitor C ₅The voltage doubling rectifing circuit of forming of boosting also is by voltage tuning knob (10) the resistance adjustment of trim-pot W to be regulated with the voltage that the high voltagehigh frequency alternating current becomes high voltage direct current, its high voltage direct current, and the adjustable extent of its voltage is between 500V～4000V.Resistance R ₃, R ₄And gauge outfit (11) and wiring point H ₁, H ₂Form metering circuit, on housing (6), leave binding post (13), so that survey pen and wiring point H ₁, H ₂Connect.The high voltage direct current that comes by boosting voltage-multiplying circuit is through wiring point H ₁, H ₂Add and place measured workpiece through surveying pen by binding post (13), the electric current of measured workpiece is directly read by gauge outfit (11), just draws the resistance of measured workpiece through converting.(12) are the zeroing screw among Fig. 4.

The course of work of this megohmmeter is gone into down, when inserting the electric main attaching plug, by the machine interpolation block switch dry cell direct current normally closed contact in the machine that breaks, connects the alternating current contact.Alternating current 220V voltage is elementary through power transformer, at the secondary 6V that reduces to.Through bridge rectifier or full-wave rectification, after electrochemical capacitor filtering, become direct current 6V again.As with dry cell in the table, then only need pull out ac plug, at this moment, just circuit can be connected in dry cell and the table.Turn on the power switch, light emitting diode brightens, the expression megohmmeter has entered duty, direct current 6V power supply becomes the low pressure high-frequency alternating current under the high-frequency oscillating circuits effect, again through step-up transformer, become the high voltagehigh frequency alternating current.The high voltagehigh frequency alternating current becomes high voltage direct current through the voltage doubling rectifing circuit of boosting, and the voltage of its high voltage direct current is regulated the adjustment of trimpot resistor value by the voltage tuning knob.This high voltage direct current added place measured workpiece, just can directly reflect the size of current of measured workpiece, just can draw the resistance of measured workpiece by converting by the gauge outfit in the metering circuit.

The utility model internal structure is simple, and labor aptitude is strong, for high-altitude field work send the power transformation circuit, the insulation of high-tension electricity porcelain vase checks the communication electric wire cable inspection. It is very convenient to test, and stable performance, and fault rate is extremely low. In use, such as long-time short circuit, electric current is excessive to be beaten when showing, and circuit can enter guard mode automatically, and vibration stops. Because operating voltage is adjustable, therefore can test the insulation workpiece of different withstand voltages, and cheap, preferably market prospects are arranged. Producing this table need not equipment investment, is suitable for medium-sized and small enterprises and practices midwifery.

Claims

1, the electronics megohmmeter, by housing parts, gauge outfit, binding post, measure portion and power unit that resistance and survey pen are formed are formed, it is characterized in that said power unit is made up of transformer and rectifier, or directly be dry cell, circuit board in the table is provided with high-frequency oscillating circuits and the voltage doubling rectifing circuit of boosting simultaneously, housing is provided with switch, said high-frequency oscillating circuits is by a triode, a transformer, two electric capacity and a resistance are formed 3 condenser type oscillators, the said voltage doubling rectifing circuit of boosting is by a boost capacitor, two rectification and voltage multiplier diodes and a filter capacitor are formed, power supply unit tap high-frequency oscillating circuits, connect the voltage doubling rectifing circuit of boosting again, connect measure portion at last.

2, according to the electronics megohmmeter of claim 1 regulation, it is characterized in that also being provided with in the high-frequency oscillating circuits trim-pot, the outer tuning knob of trim-pot and housing connects.