Universal Enterprise DMEG3 Installation Manual

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www.ueitest.com • email: [e-mail]

DMEG3/IRT3

INSTRUCTION MANUAL

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 400 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

Safety Notes

Before using this meter, 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 orgainizational standards:

• IE C 1010 CAT III, BS 16th Edition

• EN 61010

• IEC Publication 34 8

These guidlines apply apecifically to your instrument:

• Do not attempt to measure any voltage that exceeds the ca t e g o ry
based rating of this meter (CAT III, 600 Vo l t s )

• 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
c o n t i n u i ty c heck of the leads prior to making voltage 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 tothe meter or this meter is on

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

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

• S m o k e • Discoloration or melting of components

DMEG3/IRT3-MAN P. 1

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

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.

IRT (Fig 1)

• Red light indicates that the “P r ess to Te s t ” switch is pressed

• Voltage is tested without pressing “P r ess to Te s t ” 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

NOTE: If the measured value exceeds the meters range, a “l_ _” will
be shown in the display.

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.

CAUTION!

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.

International Symbols

C o n t rols and Indicators

3

DMEG3/IRT3-MAN P. 2

(IRT3)

(DMEG3)

4

2

1

4

(

Fig 1)

(Fig 2)

Analog Display (IRT3)

LCD Display (DMEG3)

Live circuit

Power ON

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.

Detecting AC Voltage

Any time AC voltage is present on the test leads, the “Live Circuit”
indicator light will illuminate. This voltage detection feature works
regardless of battery condition or powering on the instrument. With test
leads installed:

1. Ensure power is off (DMEG3) and the Press to Test is
NOT pressed.

2. Connect black test lead to the grounded or neutral side of
the circuit.

3. Connect red test lead to the hot or powered side of the circuit.

4. Observe “Live Circuit” lamp.

• Lamp illuminated: circuit is live, DO NOT test continuity

or megohms

• Lamp off: circuit is not live, testing may proceed

NOTE: Connecting the black and red test leads to the specific sides of
the circuit indicated is not critical to the measurement. Connecting the
black “EARTH” test lead to ground first is a safety discipline that can
reduce the risk of a shock hazard to the operator.

DMEG3/IRT3-MAN P. 3

Measuring AC Voltage

Voltage levels of up to 600 volts AC can be measured with your insulation
resistance tester. With test leads installed:

1. Ensure power is on (DMEG3).

2. Place rotary function select switch to the “AC 600 V” position.

3. Connect black test lead to the grounded or neutral side of
the circuit.

4. Connect red test lead to the hot or powered side of the circuit.

5. Apply power to the circuit under test.

6. Press and hold (or lock) the “Press to Test” button.

7. Observe voltage level.

8. Release the “Press to Test” button, remove power to the circuit
under test and then disconnect test leads.

WARNING!

Connecting alligator clips to live circuits presents a shock hazard.
Insulation on these clips deteriorates over time and often wears thin
from the inside, through use,. If live voltage must be tested, connect the
black clip to a KNOWN ground then use the red test lead without the
alligator clip attached to check the hot side of the circuit. Use protective
clothing and equipment when appropriate.

Measuring Continuity

Continuity testing allows you to quickly determine if two or more
points are connected electrically and it allows you to check for excessive
resistance across contacts. With its high resolution, you can compare
input to output windings on transformers or help identify a motor-type
by checking the resistance of its windings. With test leads installed:

1. Ensure no power is applied to the circuit under test
(see detecting AC voltage).

2. Ensure power is on (DMEG3).

3. Place rotary function select switch to the “Continuity” position.
(the DMEG3 has two continuity ranges)

• 2000 ohm for high-impedance testing

• 20 ohm for low impedance, high accuracy testing

4. Test continuity operation by shorting test leads together and
pressing the “Press to Test” button.

5. Connect black test lead to one side of the circuit (i.e., winding
or contact).

6. Connect red test lead to the other side of the circuit (i.e., other
end of the winding).

7. Press and hold (or lock) the “Press to Test” button.

8. A continuity tone will sound (DMEG3 only) if resistance is
below 10 ohms.

9. Observe ohm value.