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IET Labs, Inc. 1864-1644 User And Service Manual

Positive polarity megohmmeter
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PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT
1864-1644
Positive Polarity
Megohmmeter
User and Service Manual
Copyright © 2018 IET Labs, Inc.
Visit www.ietlabs.com for manual revision updates
1864-1644 im/January 2018
www.ietlabs.com
IET LABS, INC.
Email: info@ietlabs.com
TEL: (516) 334-5959 • FAX: (516) 334-5988

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Summary of Contents for IET Labs, Inc. 1864-1644

  • Page 1 PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT 1864-1644 Positive Polarity Megohmmeter User and Service Manual Copyright © 2018 IET Labs, Inc. Visit www.ietlabs.com for manual revision updates 1864-1644 im/January 2018 www.ietlabs.com IET LABS, INC. Email: info@ietlabs.com TEL: (516) 334-5959 • FAX: (516) 334-5988...
  • Page 2 ♦ ♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT www.ietlabs.com IET LABS, INC. Email: info@ietlabs.com TEL: (516) 334-5959 • FAX: (516) 334-5988...
  • Page 3 WARRANTY We warrant that this product is free from defects in material and workmanship and, when properly used, will perform in accordance with applicable IET specifi cations. If within one year after original shipment, it is found not to meet this standard, it will be repaired or, at the option of IET, replaced at no charge when returned to IET.
  • Page 4 WARNING OBSERVE ALL SAFETY RULES WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES. Dangerous voltages may be present inside this instrument. Do not open the case Refer servicing to qualifi ed personnel HIGH VOLTAGES MAY BE PRESENT AT THE TERMINALS OF THIS INSTRUMENT WHENEVER HAZARDOUS VOLTAGES (>...

  • Page 5: Table Of Contents

    1864-1644 Positive Polarity Megohmmeter Contents Condensed Operating Instructions ............iv Specifi cations .....................v 1864-1644 Specifi cations ....................v Chapter 1: INTRODUCTION ...............1 1.1 Description ....................... 1 1.2 Opening and Tilting the Cabinet ................1 1.3 Controls, Connectors and Indicators ................ 1 1.4 Symbols........................
  • Page 6 1864-1644 Positive Polarity Megohmmeter 4.3.3 Measurement Time Constant ................. 15 4.3.4 Discharge Time ....................15 4.3.5 Large Capacitors, Very High Resistance ............15 4.4 Resistance Measurements ..................16 4.5 Measurement of Voltage Coeffi cient ................ 16 4.6 Guarded 3-Terminal Measurements ................. 17 4.7 Remote Shielded Measurements ................
  • Page 7 Figures 1864-1644 Front-panel Controls, Connectors and Indicators ......... iv Figure 1-1. Type 1864-1644 Front-panel Controls, Connectors and Indicators ..2 Figure 1-2. Type 1864-1644 rear-panel controls and connectors ......4 Figure 1-3. Methods of connection to the measurement terminals ......5 Figure 2-1.

  • Page 8: Condensed Operating Instructions

    SWITCH POWER-OFF SWITCH TEST-VOLTAGE SWITCHES 1864-1644 Front-panel Controls, Connectors and Indicators 4. Connect the unknown to the UNKNOWN termi- 1. Determine which ground link connection is to be nals. used (paragraph 3.1.1 ). 5. Measure the unknown with either the search (para- 2.

  • Page 9: Specifi Cations

    1864-1644 Positive Polarity Megohmmeter Specifi cations 1864-1644 Specifi cations Rmin Rmax (right end) Voltage Useful (Full Scale left end) (10% of scale) (2.5% of scale) Setting Ranges ("0.5" rdg) ("5" rdg) ("20" rdg) 10 Vdc to 50 Vdc 50 kΩ...
  • Page 10 1864-1644 Positive Polarity Megohmmeter This page intentionally left blank. CONTENTS, FIGURES, AND TABLES...

  • Page 11: Chapter 1: Introduction

    INTRODUCTION WARNING High voltage is applied to the measurement terminals of 1864-1644 Megohmmeters at all times, except when the function switch is set to DISCHARGE. While the current is limited to a value that is not dangerous under most conditions, the energy stored in a capacitor connected to the terminals may be LETHAL.

  • Page 12: Figure 1-1. Type 1864-1644 Front-Panel Controls, Connectors And Indicators

    1864-1644 Positive Polarity Megohmmeter Figure 1-1. Type 1864-1644 Front-panel Controls, Connectors and Indicators INTRODUCTION...
  • Page 13 1864-1644 Positive Polarity Megohmmeter Figure 1.1 Name Type Function Reference POWER 2-position toggle Turn power on and off. switch Indicates the value to be 4-in. meter with Meter multiplies by the multiplier plastic cover switch. Adjusts high end of meter SET ∞...

  • Page 14: Figure 1-2. Type 1864-1644 Rear-Panel Controls And Connectors

    1864-1644 Positive Polarity Megohmmeter Figure 1-2. Type 1864-1644 rear-panel controls and connectors Table 1.2. Figure 1-2 Name Type Function Reference Power Input IEC Standard Power input Power input and circuit protection receptacle. Output Phone jack Provides a dc voltage output for recorder...

  • Page 15: Symbols

    1864-1644 Positive Polarity Megohmmeter 1.4 Symbols 1.5 Connections These instruments indicate the resistance of the The UNKNOWN, GUARD and ground terminals unknown in multiples of ohms. The relationship are standard 3/4-in. spaced binding posts that accept between ohms (Ω), kilohms (kΩ), megohms (MΩ), banana plugs, standard telephone tips, alligator clips, gigaohms (GΩ), and teraohms (TΩ) is as follows:...
  • Page 16 1864-1644 Positive Polarity Megohmmeter This page intentionally left blank. INTRODUCTION...

  • Page 17: Chapter 2: Installation

    1864-1644 Positive Polarity Megohmmeter Chapter 2 INSTALLATION Dimensions in inches Figure 2-1. Dimensions of the GR/IET 1864-1644 Megohmmeters 2.1 Initial Inspection 2.3 Repackaging for Shipment IET instruments receive a careful mechanical and If the instrument is to be returned to IET Labs, contact electrical inspection before shipment.

  • Page 18: Storage

    2.7 Power Connections If this instrument is to be stored for any lengthy The 1864-1644 Megohmmeter can be operated from period of time, it should be sealed in plastic and either a 100- to 125-V or a 200- to 250-V, 50-to 60- stored in a dry location.

  • Page 19: Chapter 3: Operation

    3.1.2 Test Voltage Selection The TEST VOLTAGE switch(es) should be set to the desired measurement voltage. The 1864-1644 Megohmmeter has a selection of 10 to 109 Vdc in 1-V steps or 100 to 1090 Vdc in 10-V steps. On the...

  • Page 20: Measurement Procedure

    1864-1644 Positive Polarity Megohmmeter 3.2 Measurement Procedure 3.2.4 Shock Hazard 3.2.1 General Either of two measurement procedures may be used, Every precaution has been taken in the design of depending on whether or not the correct resistance- 1864 Megohmmeters to reduce the possibility of multiplier range is known.

  • Page 21: Output Jack

    1864-1644 Positive Polarity Megohmmeter 3.3 Output Jack The OUTPUT jack (J105) on the rear panel makes accessible a dc voltage that is directly proportional to the reciprocal of the meter reading, that is, the highest value is at the 0.5 scale reading and the lowest value is at ∞.
  • Page 22 1864-1644 Positive Polarity Megohmmeter This page intentionally left blank. OPERATION...

  • Page 23: Chapter 4: Applications

    A com- plete charge-current-vs-time plot will provide more useful information. The 1864-1644 Megohmmeters can be used for ei- ther true leakage measurements or for measurements at 1-or 10-minute intervals following the operating procedure described in Section 3.

  • Page 24: Test Sample Resistivity Measurements

    1864-1644 Positive Polarity Megohmmeter WARNING Capacitors being measured may be charged and may contain lethal energy. Always set the function switch to DISCHARGE before connecting or disconnecting the capacitor under test. 4.3.2 Charging Time Constant The time constant for charging a capacitor in the CHARGE position is determined by the value of Figure 4-1.

  • Page 25: Measurement Time Constant

    1864-1644 Positive Polarity Megohmmeter 4.3.4 Discharge Time Dielectric absorption (dipole and interfacial polariza- tion) is present in many capacitors and insulators, With the function switch set at DISCHARGE, the especially those with a laminated structure. When UNKNOWN terminals are connected through 470 Ω...

  • Page 26: Resistance Measurements

    1864-1644 Positive Polarity Megohmmeter 1. Dielectric absorbtion. (paragraph 4.3.2). This is 4.5 Measurement of Voltage Coeffi cient the main cause of erroneous readings. Besides the diffi culty in deciding what charging period should be The 1864 Megohmmeter may be used to measure used, the previous history of the capacitor will greatly voltage coeffi...

  • Page 27: Guarded 3-Terminal Measurements

    1864-1644 Positive Polarity Megohmmeter 4.6 Guarded 3-Terminal Measurements 4.8 Measurements Under Humid Conditions In many cases it is necessary to measure the resistance between two points in the presence of resistance from The 1864 Megohmmeter has been designed to operate each of these points to a third point.
  • Page 28 1864-1644 Positive Polarity Megohmmeter This page intentionally left blank. APPLICATIONS...

  • Page 29: Chapter 5: Theory

    1864-1644 Positive Polarity Megohmmeter Chapter 5 THEORY 5.2.2 Type 1863 Megohmmeter (Figure 7.6) 5.1 General The voltage supply section (RECT.) of the 1863 The 1864 Megohmmeter basically consists of a regu- consists of fi ve different circuits, three dc and two ac.

  • Page 30: Type 1864 Megohmmeter (Figure 7.9)

    1864-1644 Positive Polarity Megohmmeter Figure 5-1 Megohmmeter block diagram 5.2.3 Type 1864 Megohmmeter (Figure 7.9) A unity-gain FET-input amplifi er (+1) follows the standard resistors in the circuit confi guration. R210 The circuit of the 1864 Megohmmeter is basically and C203 comprise a low-pass fi lter input to FET the same as that of the 1863 (paragraph 5.2.2).

  • Page 31: Chapter 6: Service And Maintenance

    1864-1644 Positive Polarity Megohmmeter Chapter 6 SERVICE AND MAINTENANCE WARNING Dangerous voltages are present inside this case. When troubleshooting, a ground strap should be connected between GUARD and GROUND on panel to keep the subpanel (Guard) at ground potential. Refer all servic- ing to qualifi...

  • Page 32: Figure 6-1. Connections For Measuring Standard Resistors

    1864-1644 Positive Polarity Megohmmeter 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).

  • Page 33: Cabinet Removal

    1864-1644 Positive Polarity Megohmmeter 6.3 Cabinet Removal To remove the instrument from the cabinet, remove the two screws on the rear of the instrument cabinet and pull the instrument out of the cabinet. Warning Be careful when troubleshooting the instrument when it is out of its cabinet and connected to the power line.

  • Page 34: Test Voltages

    1864-1644 Positive Polarity Megohmmeter If the instrument is completely inoperative, be sure to check the power-line connection and the fuse (located in the IEC power input assembly on the rear panel). 6.4.2 Test Voltages Tables 6.3 and 6.4 list a number of typical test voltages to assist in trouble analysis.

  • Page 35: Range-Resistor Accuracy

    1864-1644 Positive Polarity Megohmmeter 6.5.4 Range-Resistor Accuracy If all the voltages are out of tolerance in the same direction, they can be set within the tolerance by adjusting R140 located on etched-circuit board P/N The range resistors can be checked by performing 1864-2701 (common to both the 1863 and 1864 Meg- procedure steps in of section 6.2.

  • Page 36: Knob Removal

    1864-1644 Positive Polarity Megohmmeter 6.6 Knob Removal If it should be necessary to remove the knob on a front-panel control, either to replace one that has been damaged or to replace the associated control, proceed as follows: 1. 1. Grasp the knob fi rmly with the fi ngers,...

  • Page 37: Knob Installation

    1864-1644 Positive Polarity Megohmmeter It is treated inside and out in manufacturing with a 6.7 Knob Installation special non-abrasive anti-static solution, Statnul*, which normally should preclude any interference in To install a knob assembly on the control shaft: meter operation caused by electrostatic effects. The 1.
  • Page 38 1864-1644 Positive Polarity Megohmmeter This page intentionally left blank. SERVICE AND MAINTENANCE...

  • Page 39: Chapter 7: Parts Lists And Diagrams

    1864-1644 Positive Polarity Megohmmeter Chapter 7 PARTS LISTS AND DIAGRAMS PARTS LIST AND DIAGRAMS...
  • Page 40 1864-1644 Positive Polarity Megohmmeter PARTS LIST AND DIAGRAMS...

  • Page 41: Figure 7-1. Replaceable Mechanical Parts On The 1864-1644

    1864-1644 Positive Polarity Megohmmeter Figure 7-1. Replaceable mechanical parts on the 1864-1644 Replaceable parts list Model Ref IET Pt No Description 7910-1300-02 Power switch 5730-1412-01 Meter assembly 5520-5220-AS Knob assembly for 1863/64 potentiometers 3770-2 Red binding post 01-1008-1-0310 Gold binding post...

  • Page 42: Figure 7-3. Type 1864 Rectifi Er Circuit Etched-Board Assembly

    1864-1644 Positive Polarity Megohmmeter Figure 7-2. Regulator and amplifi er circuits etched-board assembly Figure 7-3. Type 1864 rectifi er circuit etched-board assembly (P/N 1864-2720) PARTS LIST AND DIAGRAMS...

  • Page 43: Figure 7-4 Type 1864 Switching Diagram

    1864-1644 Positive Polarity Megohmmeter PARTS LIST AND DIAGRAMS...

  • Page 44: Figure 7-5. Type 1864 Schematic Diagram

    1864-1644 Positive Polarity Megohmmeter PARTS LIST AND DIAGRAMS...

  • Page 45: Figure 7-6. Complete Cabinet Assembly

    1864-1644 Positive Polarity Megohmmeter Figure 7-6. Complete cabinet assembly PARTS LIST AND DIAGRAMS...
  • Page 46 1864-1644 Positive Polarity Megohmmeter PARTS LIST AND DIAGRAMS...

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