UEi Test Instruments DMEG3 - Manual (Page 4)

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.