Vanguard Instruments Auto-Ohm 10 User Manual

Auto-Ohm 10

Low Resistance Micro-Ohmmeter

USER’S MANUAL

Vanguard Instruments Company, Inc.

1520 S. Hellman Ave.
Ontario, California 91761, USA

TEL: [phone]
FAX: [phone]

May 16, 2017

Revision 1.0

Auto-Ohm 10 USER’S MANUAL REV 1.0

SAFETY SUMMARY

FOLLOW EXACT OPERATING PROCEDURES

Any deviation from the procedures described in this user’s manual may create one or more safety hazards,
damage the Auto-Ohm 10, or cause errors in the test results. Vanguard Instruments Co., Inc. assumes no liability
for unsafe or improper use of the Auto-Ohm 10. The following safety precautions must be observed during all
phases of test setup, test hookups, testing, and test lead disconnection.

SAFETY WARNINGS AND CAUTIONS

The Auto-Ohm 10 shall be used only by trained operators. All circuit breakers under test shall be off-line and fully
isolated.

SERVICE AND REPAIR

• Do not install substitute parts or perform any unauthorized modification to any Auto-Ohm 10 test unit.

• Repairs must be performed only by Vanguard Instruments Company factory personnel or by an authorized

repair service provider. Unauthorized modifications can cause safety hazards and will void the manufacturer’s
warranty.

EQUIPMENT RATINGS

IP Rating: The enclosure for the Auto-Ohm 10 has an IP rating of 67.

Pollution Degree: The Auto-Ohm 10 has a pollution rating of 2.

Operating Voltage: The Auto-Ohm 10 is rated for use with an operating voltage of 120V or 240V, auto-ranging

±10% of selected voltage.

Power Cord: The Auto-Ohm 10 is supplied with a 16 AWG, 16A power cord with a NEMA 5-15P plug. Replacement
cable shall have the same or better rating and is available through the manufacturer.

VENTILATION REQUIREMENTS

The Auto-Ohm 10 must be operated with the enclosure lid open.

SAFETY SYMBOLS

Indicates that caution should be exercised

CLEANING

To clean the Auto-Ohm 10:

• Disconnect all cables and turn the unit off.

• Use a soft, lint-free cloth to wipe all surfaces clean.

• Avoid getting moisture in openings and connectors.

• Don't use any cleaning products or compressed air.

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REV 1.0 Auto-Ohm 10 USER’S MANUAL

TABLE OF CONTENTS

CONVENTIONS USED IN THIS DOCUMENT ....................................................................... 1

1.0 INTRODUCTION .................................................................................................................... 2

1.1 Product Overview ............................................................................................................ 2

1.2 Technical Specifications ................................................................................................... 5

1.3 Auto-Ohm 10 Controls and Indicators ............................................................................. 6

1.4 PRE-TEST SETUP ................................................................................................................... 7

1.4.1. Operating Voltages ................................................................................................... 7

1.4.2. Installing the Battery Fuse ........................................................................................ 7

1.4.3. Replacement Rechargeable Batteries ...................................................................... 8

1.4.4. Charging and Turning the Unit On and Off .............................................................. 8

1.4.5. Adjusting LCD Screen Contrast ................................................................................. 9

1.4.6. Configuring Power Saving Options ......................................................................... 10

1.4.7. Viewing Previous Test Results ................................................................................ 13

2.0 OPERATING PROCEDURES ................................................................................................. 14

2.1 Connection Diagram ...................................................................................................... 14

2.2 Contact Resistance Tests ............................................................................................... 15

2.2.1. Configuring Contact Resistance Tests .................................................................... 15

2.2.2. Performing a Contact Resistance Test ................................................................... 18

2.3 Performing a Transformer Winding Resistance Test ..................................................... 20

3.0 Upgrading Firmware .......................................................................................................... 22

4.0 Troubleshooting Guide ...................................................................................................... 26

LIST OF TABLES

Table 1. Auto-Ohm 10 Technical Specifications ............................................................................. 5

LIST OF FIGURES

Figure 1. Included Cable Set with Alligator Clamps (P/N 8000-0231) ............................................ 3

Figure 2. Optional 10A Rated Pistol Grip Probe (P/N 8000-0201) .................................................. 3

Figure 3. Optional 10A Rated Hand Probe (P/N 8000-0225) .......................................................... 4

Figure 4. Optional 5A Rated Hand Probe (P/N 8000-0226) ............................................................ 4

Figure 5. Auto-Ohm 10 Controls and Indicators ............................................................................. 6

Figure 6. Battery Fuse in Protective Plastic Box ............................................................................. 7

Figure 7. Panasonic Orbtronic 18650 Protected Li-ion Battery ...................................................... 8

Figure 8. Typical Auto-Ohm 10 Connection Diagram ................................................................... 14

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Auto-Ohm 10 USER’S MANUAL REV 1.0

1.0 INTRODUCTION

1.1 Product Overview

The Vanguard Auto-Ohm 10 is a 10-ampere battery powered micro-ohmmeter designed for
low-resistance-measuring applications such as the measurement of resistance in circuit breaker
contacts, bushing contact joints, and welding joints. The unit is powered by four 3400mAh,

3.7Vdc Li-Ion rechargeable batteries. With these high capacity batteries, up to 2,900 tests per
charge (10A/2 second duration) can be performed in the field. The Auto-Ohm 10 features a
built-in charger that can charge the batteries when the unit is not in use.

The Auto-Ohm 10 features a rotary knob that is used to select either the “Contact Resistance”
or “Transformer Resistance” test mode. The unit's back-lit LCD screen (128 x 64 pixels) is
viewable in both direct sunlight and low light level. Resistance readings are displayed on the
LCD screen in micro-ohms, milliohms, or ohms.

Contact Resistance Mode

The “Contact Resistance” mode can measure resistance values from 1 micro-ohm to 5,000
Ohms. The user can select from 6 different test currents: 1mA, 10mA, 100mA, 1A, 5A, 10A. The
user can also choose from 6 test times: 1 sec, 2 sec, 3 sec, 5 sec, 10 sec, 60 sec. Up to three
tests can be pre-configured with any combination of these parameters and executed with a
single push of the control switch.

The Auto-Ohm 10 also offers a “Bi-directional” test mode. In this mode, the test current is
applied in both directions to the device under test and the readings are recorded. The final test
result is the average reading of the bi-directional resistance values. An "Auto" test mode is also
available that will start a test once a user applies the test leads to the device under test. The
last three readings are displayed on the LCD screen.

Transformer Resistance Mode

In “Transformer Resistance” test mode, the Auto-Ohm 10 can measure the winding resistance
of transformers, electric motors, and generators. It provides 4 test currents (100mA, 1A, 5A,
10A) and can measure the winding resistance of a 3-phase 500KVA/12,000V transformer within
1 minute. At the end of a winding resistance test, the Auto-Ohm 10 automatically dissipates the
stored energy in the transformer.

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REV 1.0 Auto-Ohm 10 USER’S MANUAL

Cables and Accessories

The Auto-Ohm 10 is furnished with a 15 ft (4.57m) cable set with alligator clamps (P/N 8000-

0231). The test current and voltage sense cables are isolated on the alligator clamps. With this
feature, only a single connection is needed to the device under test. Optional 10A rated pistol
grip probe (P/N 8000-0201), 10A rated hand probe (P/N 8000-0226), and 5A rated hand probe
(P/N 8000-0225) are also available.

Figure 1. Included Cable Set with Alligator Clamps (P/N 8000-0231)

Figure 2. Optional 10A Rated Pistol Grip Probe (P/N 8000-0233)

3

Auto-Ohm 10 USER’S MANUAL REV 1.0

Figure 3. Optional 10A Rated Hand Probe (P/N 8000-0225)

Figure 4. Optional 5A Rated Hand Probe (P/N 8000-0226)

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Auto-Ohm 10 USER’S MANUAL REV 1.0

1.3 Auto-Ohm 10 Controls and Indicators

The Auto-Ohm 10’s controls and indicators are shown in Figure 5. The purpose of the controls
and indicators may seem obvious, but users should familiarize themselves with them before
using the Auto-Ohm 10. Accidental misuse of the controls will usually cause no serious harm.
Users should also familiarize themselves with the safety summary information found on the
front page of this User’s Manual.

Figure 5. Auto-Ohm 10 Controls and Indicators

6