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IET Labs KVD-700 Series Operation Manual

Kelvin-varley voltage divider
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PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT
Effectivity: Serial Numbers prefixed G
KVD-700im/08-07
IET LABS, INC.
534 Main Street, Westbury, NY 11590
KVD-700 SERIES
KELVIN-VARLEY
VOLTAGE DIVIDER
Operation Manual
Copyright © 2007 IET Labs, Inc.
TEL: (516) 334-5959 • (800) 899-8438 • FAX: (516) 334-5988
♦
www.ietlabs.com

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Summary of Contents for IET Labs KVD-700 Series

  • Page 1 ♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT KVD-700 SERIES KELVIN-VARLEY VOLTAGE DIVIDER Operation Manual Copyright © 2007 IET Labs, Inc. Effectivity: Serial Numbers prefixed G KVD-700im/08-07 IET LABS, INC. www.ietlabs.com 534 Main Street, Westbury, NY 11590 TEL: (516) 334-5959 • (800) 899-8438 • FAX: (516) 334-5988...
  • Page 2 ♦ ♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT IET LABS, INC. www.ietlabs.com 534 Main Street, Westbury, NY 11590 TEL: (516) 334-5959 • (800) 899-8438 • 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 specifications. 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. 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.

  • Page 4: Warning

    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 qulified personnel HIGH VOLTAGES MAY BE PRESENT AT THE TERMINALS OF THIS INSTRUMENT WHENEVER HAZARDOUS VOLTAGES (>...

  • Page 5: Table Of Contents

    Contents WARRANTY ...................iii WARNING ....................v CAUTION ....................v Chapter 1 INTRODUCTION ................1 1.1 General Description ............... 1 1.2 Circuit Description ..............2 1.2.1 Model ................2 1.2.2 Theory of Operation ............2 Chapter 2 SPECIFICATIONS ................. 5 Chapter 3 INSTALLATION ................
  • Page 6 6.6.1 Decade B ..............19 6.6.2 Decade C ..............21 6.6.3 Decade D ..............21 6.6.4 Decade E ..............22 6.6.5 Decade F ..............22 6.6.6 Decade G ..............22 6.7 Calibration ................23 6.7.1 Calibration of C Decade..........23 6.8 Bridge Calibration ..............

  • Page 7: Chapter 1 Introduction

    KVD-700 Chapter 1 INTRODUCTION 1.1 General Description The switches used have gold plated solid silver alloy contacts for long life, minimum contact resistance, The KVD-700 (Figure 1.1) is a calibration grade volt- and no tarnishing. Gold also allows the use with low age divider employing the Kelvin-Varley circuit.

  • Page 8: Circuit Description

    KVD-700 1.2 Circuit Description be seen that the output impedance is maximum at about the dial setting of 0.5 and drops to zero at both ends, 1.0 and 0. It is the value of R which will influ- ence the effect of loading. 1.2.1 Model Note, however, that in general bridge applications, nominally zero current flows out of the divider as the...

  • Page 9: Figure 1.4. Approximate Value Of Output Resistance As A Function Of Dial Setting (S)

    KVD-700 RATIO DIAL SETTINGS (S) Note: The value of the output resistance is a “smoothed” approximation. The actual resistance “oscillates” around this value as lower decades are varied. Figure 1.4. Approximate Value of Output Resistance as a Function of Dial Setting (S) Each step of the second decade is also 10 kΩ.

  • Page 10: Figure 1.5. Schematic Diagram Of Kvd-700 Kelvin-Varley Voltage Divider Circuit

    Figure 1.5. Schematic Diagram of KVD-700 Kelvin-Varley Voltage Divider Circuit...

  • Page 11: Specifications

    KVD-700 Chapter 2 SPECIFICATIONS For convenience to the user, the pertinent specifica- Temperature Coefficient of Input Resistance: tions are given in an OPERATING GUIDE, typi- ±1.0 ppm/ºC. cally shown in Figure 2.1, affixed to the case of the Maximum Input Power: instrument.

  • Page 13: Chapter 3 Installation

    Chapter 3 INSTALLATION 3.3 Repackaging for Shipment If the instrument is to be returned to IET Labs, con- tact the Service Department at the number or ad- 3.1 Initial Inspection dress, shown on the front cover of this manual, to obtain a “Returned Material Authorization”...

  • Page 14: Chapter 4 Operation

    KVD-700 Chapter 4 OPERATION 4.1 Initial Inspection and Setup the unit should be allowed to cool for a few hours before the application of low power. This instrument was carefully inspected before ship- 4.3 Loading Errors ment. It should be in proper electrical and mechani- cal order upon receipt.

  • Page 15: Switch Conditioning

    KVD-700 tively draw no current from the KVD-700 and ap- 100% of a nominal value is required. Secure con- proach a true open circuit. nections should be made to the terminals using spade lugs, banana jacks, or bare wire. Caution should be exercised since most often such connectors are usu- 4.4 Switch Conditioning ally made of brass which can add thermal emf.

  • Page 16: Representative Bridge Applications Of The Kvd-700

    There is a broad spectrum of applications for a Kelvin- brating the KVD-700. Varley divider, such as calibrating other voltage divid- ers, measuring unknown voltages, and measuring un- Consult IET Labs for additional references and in- known resistances. There are a number of sources formation. Operation...

  • Page 17: Chapter 5 Self-Calibration

    KVD-700 Chapter 5 SELF-CALIBRATION 5.1 Introduction out consideration for end errors. This is done for ex- ample, when two dividers are compared to each other. In other applications, this is not practical and the end As may be seen from the schematic of a Kelvin-Var- error corrections must be applied.

  • Page 18: Figure 5.2. Setup Diagram For Measurement Of Zero End Correction Relative To Output Common

    KVD-700 Figure 5.1. Setup Diagram for Measurement of Zero End Correction Relative to Input Common Figure 5.2. Setup Diagram for Measurement of Zero End Correction Relative to Output Common Figure 5.3. Setup Diagram for Measurement of Full Scale Correction 8-07 Self-Calibration...

  • Page 19: Self-Calibration Setup

    KVD-700 5.3 Self-Calibration Setup 3. Set the null detector to zero with its offset or zero control. 4. Set the dc voltage supply to 20 V. , Refer to Figure 5.4 to set up the KVD-700 for self 5. Connect the dc voltage supply as shown to the calibration.

  • Page 20: Second Decade

    KVD-700 5.4.2 Second Decade 5.4.3 Shunt Resistors 1. Set the KVD-700 switches to .0000000 1. Set the KVD-700 switches to .0000000 2. Set the MODE switch on the KVD-700 2. Set the null detector to zero with its offset or to CAL A.

  • Page 21: Verification, Calibration And Maintenance

    Figure 6.8. Parts Location: Front Panel KVD7-6500 for Knob KVD-700-100 Calibration board (visible from bottom) KVD7-2200 KVD-700-200 KVD7-6510 for Cap (board visible from bottom) INTERNAL IET LABS COMP SIDE MODE KVD-700-200 BRIDGE BOARD KVD-4500 OIL CAN IET LABS KVD7-1510 COMPONENT SIDE...

  • Page 22: Verification Of Absolute Linearity Of First Decade

    KVD-700 Figure 6.10. Parts Location: Calibration PC Board Verification, Calibration and Maintenance...

  • Page 23: Bibliography

    KVD-700 Appendix A BIBLIOGRAPHY 2. M. L. Morgan and J. C. Riley, “Calibration of The following articles may be useful in understanding Kevin-Varley Voltage Divider,” IRE Trans. the use and calibration of a Kelvin-Varley voltage di- on Instrumentation, vol 1-9, pp 237-243; Sept. vider.

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