IET Labs, Inc. 1864-1644 Скачать руководство пользователя страница 32 | Manualshive

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IET Labs, Inc. 1864-1644 Скачать руководство пользователя страница 32

SERVICE AND MAINTENANCE

1864-1644 Positive Polarity Megohmmeter

22

16.

Set the POWER/OFF

switch to

OFF

and

disconnect the decade resistor.

17. Connect the Digital Multimeter between the

GUARD

and

-UNKNOWN

terminals

with two single banana plug patch
cords.

18. Connect the two ground terminals together

with a third patch cord (Figure 6.1).

The megohmmeter shorting link
should remain attached only to the
ground terminal.

19. Set the multiplier switch in the full ccw posi-

tion (1M, 100k) and the function switch
to MEASURE.

20. Measure the various standard resistors of the

megohmmeter with the DMM according
to the settings and tolerances of Table
6.2. Use the IET LOM-510A megohm-
meter for resistance values beyond the
range of the DMM.

Figure 6-1. Connections for measuring standard
resistors with a digital multimeter

+

-

«
...
30
31
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Содержание 1864-1644

Страница 1: ...ervice Manual Copyright 2018 IET Labs Inc Visit www ietlabs com for manual revision updates 1864 1644 im January 2018 PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT Email info ietlabs com TEL 516 334...

Страница 2: ...PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT Email info ietlabs com TEL 516 334 5959 FAX 516 334 5988 www ietlabs com IET LABS INC...

Страница 3: ...at no charge when returned to IET Changes in this product not approved by IET or application of voltages or currents greater than those allowed by the specifications shall void this warranty IET shall...

Страница 4: ...E USED TAKE ALL MEASURES TO AVOID ACCIDENTAL CONTACT WITH ANY LIVE COMPONENTS USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE CONDUCTORS WHEN USING THIS INSTRUMENT Use extreme caution when working...

Страница 5: ...pection 7 2 2 Dimensions 7 2 3 Repackaging for Shipment 7 2 4 Storage 8 2 5 Bench Setup 8 2 6 Rack Mounting 8 2 7 Power Connections 8 Chapter 3 OPERATION 9 3 1 Measurement Setup 9 3 1 1 Ground Link Co...

Страница 6: ...7 Chapter 5 THEORY 19 5 1 General 19 5 2 Circuit Description 19 5 2 1 General 19 5 2 2 Type 1863 Megohmmeter Figure 7 6 19 5 2 3 Type 1864 Megohmmeter Figure 7 9 20 Chapter 6 SERVICE AND MAINTENANCE 2...

Страница 7: ...1 Electrode arrangement for resisitivity measurements 14 Figure 4 2 Basic megohmmeter circuit 15 Figure 4 3 Guarded measurement of a three terminal resistor 16 Figure 5 1 Megohmmeter block diagram 20...

Страница 8: ...ragraph 3 1 2 3 Set the adjustments paragraph 3 1 3 Condensed Operating Instructions 4 Connect the unknown to the UNKNOWN termi nals 5 Measure the unknown with either the search para graph 3 2 2 or so...

Страница 9: ...left end However resistance values read naturally increas ing from left to right Voltage Accuracy across unknown For 100 V 2 For 100 V 3 0 5 V 10 of scale 5 rdg 2 5 of scale 20 rdg 10 Vdc to 50 Vdc 50...

Страница 10: ...CONTENTS FIGURES AND TABLES 1864 1644 Positive Polarity Megohmmeter vi This page intentionally left blank...

Страница 11: ...etc Section 4 The 1864 has a voltage range from 10 to 1090 V that can be set in 1 Vdc steps from 10 to 109 V and in 10 V steps from 100 to 1090 V by using the TEST VOLTAGE switches on the front panel...

Страница 12: ...INTRODUCTION 1864 1644 Positive Polarity Megohmmeter 2 Figure 1 1 Type 1864 1644 Front panel Controls Connectors and Indicators 1 2 3 4 7 6 11 10 9 8 5 12...

Страница 13: ...guarded measurements It can accept a shorting link to the ground post 6 Ground Uninsulated binding post Grounds the Unknown or guard Contains a shorting link 7 UNKNOWN Insulated binding post Connects...

Страница 14: ...nput receptacle Power input and circuit protection 2 Output Phone jack Provides a dc voltage output for recorder operation 3 Line Voltage 2 position slide switch Connects wiring of power transformer f...

Страница 15: ...6 k 103 M 1 T 1012 109 k 106 M 103 G 1 5 Connections The UNKNOWN GUARD and ground terminals are standard 3 4 in spaced binding posts that accept banana plugs standard telephone tips alligator clips cr...

Страница 16: ...INTRODUCTION 1864 1644 Positive Polarity Megohmmeter 6 This page intentionally left blank...

Страница 17: ...both the rack and bench mounted configurations in Figure 2 1 2 3 Repackaging for Shipment If the instrument is to be returned to IETLabs contact the Service Department at the number or address shown o...

Страница 18: ...egohmmeter can be operated from either a 100 to 125 V or a 200 to 250 V 50 to 60 Hz power line Before connecting the 3 wire IEC power cord to the line set the slide switch on the rear panel to the pro...

Страница 19: ...igh voltages Figure 3 1 Ground link connection to GUARD terminal top and to UNKNOWN terminal bottom 3 1 3 Set Adjustments To adjust the SET controls proceed as follows 1 Turn the instrument on 2 Set t...

Страница 20: ...ide of the meter case with strips of masking tape 6 Make measurements towards the low end of the meter scale whenever possible for best accuracy and resolution 3 2 4 Shock Hazard Every precaution has...

Страница 21: ...GE RX where VTEST is the TESTVOLTAGE setting RRANGE is the lower value for a particular multiplier dial set ting 100k for the 1 M 100 k range and Rx is the value of the resistance being measured The o...

Страница 22: ...OPERATION 1864 1644 Positive Polarity Megohmmeter 12 This page intentionally left blank...

Страница 23: ...sults of such a measurement are apt to be more dependent on the dielectric absorption of the insulator than on its true leakage resistance measured at equilibrium A com plete charge current vs time pl...

Страница 24: ...stance is substantially higher than the true leakage resistance even though the charging current theoretically never reaches zero As an example a 1 F capacitor with a leakage resis tance of 1010 measu...

Страница 25: ...ger Figure 4 2 Basic megohmmeter circuit 4 3 4 Discharge Time With the function switch set at DISCHARGE the UNKNOWN terminals are connected through 470 and the discharge time is approximately 0 0005 x...

Страница 26: ...s are transmitted to the voltmeter unattenuated This difficulty can be reduced if the line voltage is regulated Slow drift of the test volt age can cause erroneous readings if RS CX is large because e...

Страница 27: ...some distance from the instrument if care is used to prevent leakage between the connecting leads and to avoid the shock hazard A convenient way to do this is to use a shielded cable If the unknown c...

Страница 28: ...APPLICATIONS 1864 1644 Positive Polarity Megohmmeter 18 This page intentionally left blank...

Страница 29: ...fic com ponents from the schematic diagrams of the 1863 Figure 7 6 and 1864 Figure 7 9 to the general components shown in Figure 5 1 5 2 2 Type 1863 Megohmmeter Figure 7 6 The voltage supply section R...

Страница 30: ...ning two resistors R221 and R223 are used for the 250 and 100V ranges respectively Potenti ometer R243 is an adjustable control in the meter sensitivity circuit 5 2 3Type1864Megohmmeter Figure7 9 The...

Страница 31: ...minal with the shorting link 2 Set the decade resistor to 0500000 500 k 3 Set the TEST VOLTAGE switch to to 1 0 0V 4 Set the multiplier switch to 1 M 5 Set the POWER OFF switch to POWER 6 Adjust the t...

Страница 32: ...third patch cord Figure 6 1 The megohmmeter shorting link should remain attached only to the ground terminal 19 Set the multiplier switch in the full ccw posi tion 1M 100k and the function switch to...

Страница 33: ...ohmmeters An understanding of the theory involved in these instruments Section 5 makes the instrument easy to analyze because the problem can usually be located quickly in either the voltage regulator...

Страница 34: ...a tremendous number of measurements 6 5 2 Meter Tracking The scale tracking can be easily checked using a de cade resistance decade box with 100 k and 1 M steps Steps a through m of paragraph 6 2 shou...

Страница 35: ...e correct but all meter readings are in error in the same direction the meter sensitiv ity can be reset Adjust R243 Figures 6 2 and 6 4 located on the same etched circuit board as R 140 to correct the...

Страница 36: ...e panel CAUTION Do not pull on the dial to remove a dial knob as sembly Always remove the knob first To avoid damage to the knob and other parts of the control do not pry the knob loose with a screwdr...

Страница 37: ...ffects The problem is evidenced by the inability of the meter movement to return promptly to a zero reading once it is deenergized As supplied by IET the meter should return to zero reading within 30...

Страница 38: ...SERVICE AND MAINTENANCE 1864 1644 Positive Polarity Megohmmeter 28 This page intentionally left blank...

Страница 39: ...1864 1644 Positive Polarity Megohmmeter 29 PARTS LIST AND DIAGRAMS Chapter 7 PARTS LISTS AND DIAGRAMS...

Страница 40: ...1864 1644 Positive Polarity Megohmmeter 30 PARTS LIST AND DIAGRAMS...

Страница 41: ...1 7910 1300 02 Power switch 2 5730 1412 01 Meter assembly 3 5520 5220 AS Knob assembly for 1863 64 potentiometers 4 3770 2 Red binding post 5 01 1008 1 0310 Gold binding post 6 1864 1200 Dial assembly...

Страница 42: ...1644 Positive Polarity Megohmmeter 32 PARTS LIST AND DIAGRAMS Figure 7 2 Regulator and amplifier circuits etched board assembly Figure 7 3 Type 1864 rectifier circuit etched board assembly P N 1864 2...

Страница 43: ...1864 1644 Positive Polarity Megohmmeter 33 PARTS LIST AND DIAGRAMS Figure 7 4 Type 1864 switching diagram...

Страница 44: ...1864 1644 Positive Polarity Megohmmeter 34 PARTS LIST AND DIAGRAMS Figure 7 5 Type 1864 schematic diagram...

Страница 45: ...1864 1644 Positive Polarity Megohmmeter 35 PARTS LIST AND DIAGRAMS Figure 7 6 Complete cabinet assembly...

Страница 46: ...1864 1644 Positive Polarity Megohmmeter 36 PARTS LIST AND DIAGRAMS...

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