UEi DMEG3/IRT3 Instruction Manual

1-800-547-5740 • Fax: [phone]

www.ueitest.com • email: [e-mail]

DMEG3/IRT3

Insulation Resistance Tester

INSTRUCTION MANUAL

TABLE OF CONTENTS

Introduction ..........................................................................................1

Safety ....................................................................................................... 2

International Symbols ....................................................................5

Controls

Power Switch ...................................................................................6

Rotary Function Select Switch ......................................................6

Press to Test .................................................................................... 6

Resistance Null Adjust ...................................................................6

Indicators

LCD Display ..................................................................................... 8

Power On Indicator ........................................................................ 8

Live Circuit Indicator ..................................................................... 8

Operation

Installing Test Leads ....................................................................... 9

Detecting AC Voltage ...................................................................10

Measuring AC Voltage .................................................................11

Measuring Continuity ..................................................................12

Measuring Insulation Resistance ................................................ 13

Temperature Correction .............................................................. 16

Preparing Equipment Under Test ..............................................18

To Make An Extended Term Analysis ........................................23

Maintenance

Service ............................................................................................ 24

Cleaning ......................................................................................... 24

Battery Replacement .................................................................... 24

Fuse Replacement ........................................................................25

Specifications

Measurement Limits ....................................................................26

General Specifications .................................................................26

Specification Table .......................................................................27

Warranty and Service Information ........................................... 30

i

Introduction

Your UEi Megohmeter allows you to predict, prevent and
identify insulation failures that can cause appliance failure, stop
production, create power problems and even put lives at risk. It
quickly tests insulation integrity on motors, power distribution
systems and other installed wiring.

All insulation has a limited life span and environmental factors
such as heat, cold and airborne chemicals can rapidly decrease
an insulating material’s predicted life. Use this instrument to
help you quickly and safely determine your insulation’s integrity.

Features include

• Large digital display that shows the test function along
with the measured value on the DMEG3 or a high-contrast
analog display on the IRT3

• AC Voltage measurement to 600 Volts

• Insulation resistance readings from 0 to 2000 Megohms

with the DMEG3 or 200 Megohms with the IRT3

• Three test-voltage ranges (250, 500, 1000 V DC)

• Live circuit (external voltage applied) warning light

• Fuse protected against accidental misuse

• Precision resistance measurement to 0.01 ohms with

audible continuity (DMEG3 only)

• 200 mA short-circuit continuity test current for high

accuracy (DMEG3 only)

• Precision, low resistance test leads
(1000 Volt CAT III rated)

• Audible continuity (DMEG3 only)

• Green LED power-on indicator (DMEG3 only)

• Low battery indication/detection

• Maintains rated voltage on cables with up to
1 mA leak-rate

• Automatic, post-test cable discharge

• Rugged, compact case with latching cover to keep

the elements out

1

Safety Tips

Before using this instrument, read all safety information
carefully. In this manual the word “WARNING” is
used to indicate conditions or actions that may pose
physical hazards to the user. The word “CAUTION” is
used to indicate conditions or actions that may damage
this instrument.

This Megohmeter is designed and manufactured in
accordance with the following organizational standards:

• IEC1010 CAT III, BS 16th Edition

• EN61010

• IEC Publication 348

These guidelines apply specifically to your instrument:

• DO NOT attempt to measure any voltage that exceeds the
category based rating of this meter (CAT III, 600 Volts)

• DO NOT attempt to use this meter if either the meter or
the test leads have been damaged. Return the damaged
meter to UEi for repair or replace your test leads

• Ensure meter leads are fully seated and operable by

making a quick continuity check of the leads prior to
making voltage or insulation resistance measurements

• Keep your fingers away from the test lead’s metal probe
contacts when making measurements. Always grip the
leads behind the finger guards molded into the probes

• DO NOT open the bottom of the meter to replace
batteries or the fuse while the probes are connected
to the meter or this meter is on

2

This meter was designed for use by service professionals
who know the hazards associated with their trade. Exceeding
the specified limits of this meter is dangerous and can cause
serious injury. To ensure safe and appropriate use, please
observe the following safety guidelines:

• Follow manufacturer’s specified testing and
troubleshooting procedures for the equipment you are
working on

• Protect yourself from direct contact with voltages above
60 volts DC or 25 volts AC, as they may constitute a
serious shock hazard

• Always turn off power to a circuit (or assembly) under
test before cutting, unsoldering, or breaking the current
path. Even small amounts of current can be dangerous

• Always disconnect the live (normally red) test lead before

disconnecting the common (normally black) test lead
from a circuit

• In the event of electrical shock, ALWAYS bring the victim

to the emergency room for evaluation, regardless of the
victim’s apparent recovery

Electrical shock can cause an unstable heart rhythm
that may need medical attention.

3

Higher voltages require greater awareness of physical safety
hazards. When it’s possible to make clip-on connections to the
circuit under test, make the connections without power applied:

1. Turn off the power to the circuit under test.

2. Set the meter to the AC 600 Volt position.

3. Connect the test leads to the meter and then to the

circuit under test.

4. Reapply power.

5. Record measurement or adjust equipment as necessary.

6. Turn off power and disconnect test leads.

If any of the following indications occur during testing, turn off
the power source to the circuit under test:

• Arcing • Extreme heat

• Flame • Smell of burning materials

• Smoke • Discoloration or melting of components

WARNING!

If any of the above conditions occur, DO NOT attempt to
remove the meter leads from the circuit under test. The
leads, meter, or circuit under test may have degraded to the
point that they no longer provide protection from the voltage
and current applied. If any of these erroneous readings are
observed, disconnect power immediately. Recheck the physical
condition of the test instrument, equipment and all settings
and connections.

4

International Symbols

5

6

Controls and Indicators

(IRT3)

(DMEG3)

1

2

3

4

4

1. Power Switch: Turns instrument power off and on.

2. Rotary Function Select Switch: Selects measurement
mode and scale.

3. Press to Test: Press this button down to initiate any
measurement function. Turn to the right while pressing to
lock the button into the test mode.

4. Resistance Null Adjust:
(DMEG3) Used to adjust meter to indicate 0.00 ohms with
the function select switch in the continuity position, the
red and black leads clipped together and the “Press to
Test” button pressed.

(IRT3) Used to pre-adjust needle movement to 0 volts
(infinite ohms) prior to use. Or you can adjust meter
to indicate 0 ohms on the green scale with the function
select switch in the continuity position, the red and
black leads clipped together and the “Press to Test”
button pressed.

7

IRT3 (Fig 1)

• Red light indicates that the “Press to Test” switch is pressed

• Voltage is tested without pressing “Press to Test” switch

DMEG3 (Fig 2)

• Green light indicates that the ON - OFF switch is turned on

• Orange indicates high voltage is being generated by the

Megohmeter for insulation resistance testing

CAUTION!

Live Circuit Indicator - Indicates that live voltage is present
on the test leads. The ONLY measurement you can take is AC
Voltage if this light is lit.

(Fig 1)

(Fig 2)

Analog Display (IRT3)

LCD Display (DMEG3)

Live circuit

Power ON

8

Operating Instructions

Prior to operating your insulation resistance tester, inspect your
instrument for:

1. Cracks or damage to the housing.

2. Water intrusion or condensation on the display.

3. Damaged test leads.

4. Low batteries.

• Check the IRT3 by pressing the Press to Test
button - the red LED light should flash rapidly if
batteries are good

• Check the DMEG3 by turning the instrument
power on and pressing the Press to Test button
if defective, “Lo Bat” will be displayed on the LCD

5. Properly installed and fully seated test leads.

• Black test lead is inserted in the “EARTH” jack

• Red test lead is inserted in the “LINE” jack

Replace the test leads if there is any visible or measurable
damage. Replace batteries if needed (refer to the maintenance
section of this manual). If there is any damage to the
instrument, it must be returned to UEi for repair.

Installing Test Leads

Test leads must be installed prior to any measurement or
detection procedure.

1. Connect the black test lead to “EARTH”, ensuring it is

fully seated.

2. Connect the red test lead to “LINE”, ensuring it is

fully seated.

9