Megger DLRO10HDX Data sheet

10 A Digital Low Resistance Ohmmeter

DLRO10HDX

10 Amp Digital Low Resistance

■ NEW Onboard memory storage for test

results up to 200 records (HDX only)

■ Download to PowerDB

■ NEW interchangeable test lead terminations

■ High or low output power selection for

condition diagnosis

■ Operates from battery or AC mains supply

■ Protected to 600 V without blowing a fuse,

test lead live voltage warning light

■ Heavy duty case: IP 65 lid closed,

IP54 operational

DLRO10HDX

DESCRIPTION

Augmenting Megger’s DLRO10 and 10X range the
DLRO10HDX combines ultimate simplicity of operation with
a rugged IP65 case designed for stable ground and bench
operation and provides memory storage.

These units are powered from either rechargeable battery
or AC power making it suitable for continuous testing in
production line/repetitive use environments.

Rotary switch controls are simple and easy to operate in all
weather conditions and with gloved hands. A large, clear,
backlit LCD display is easy to read from a distance. The
DLRO10HDX provides significantly enhanced compliance
and is capable of delivering 10 A into measurements up
to 250 mΩ and 1 A into measurements up to 2.5 Ω. The
duration of each test may be up to 60 seconds.

The DLRO10HDX is rated CAT III 300 V provided the
optional terminal cover is fitted to the instrument. Details can
be found in the ordering information panel of this data sheet.

The DLRO10HDX provides five test modes each of which is
selected through a simple rotary control on the Mode selection
rotary switch. All memory functions, delete, download to
PowerDB and recalling test results are also accessible via the
Range Selection rotary switch.

A simple control panel enables easy navigation for
configuration settings.

■ Simple rotary switch selection of five test

modes, including auto start on connection

History of ‘DUCTER’ Testing

For over 100 years the ‘Ducter’ test has been used to describe
a simple test for measuring ver low contact resistances and
‘Ducter’, which is still used as a trademark, was the name
origianally given to the low resistance ohmmeter manufactured
by Megger. The name ‘Ducter’ was registered by Megger in
June 1908 and ‘Ducter’ has since become the inudstry standard.

FEATURES AND BENEFITS

n Rugged case well suited to transportation with shoulder

strap and lead set pouch

n Removable lid facilitates easy test lead connection

n Operational ingress protection is IP 54 (battery power only)

ensuring protection from the elements

n 7Ah lead acid battery provides extended operation and can

be charged whilst operating from line power

n Rotary mode switch with bidirectional (current reversal with

averaging cancels thermal EMFs), unidirectional, automatic,
continuous and inductive modes

n Large, clear LCD display with backlight and contrast

adjustment

n Auto power off function conserves battery

DLRO10HDX

10 A Digital Low Resistance Ohmmeter

APPLICATIONS

The DLRO10HDX measures low resistance values in applications
ranging from railways and aircraft to resistance of components
in industry.

Any metallic joint can be measured but users must be aware
of measurement limitations depending on application. For
example, if a cable manufacturer plans to make resistive
measurements on a thin wire, a low test current should be
selected to prevent heating the wire thereby changing its
resistance.

Measurements on electric motors and generators will
be inductive and require the user to understand the
inductive mode and charging process before a correct result
is achieved.

The DLRO10HDX is well suited to measuring thick conductors,
bonds and quality of welding because of its 10 A range for
resistance values up to 250 mΩ.

Electromagnetic noise induced into the leads can interfere
with a reading. A noise symbol alerts the user and prevents
a measurement when the instrument detects noise above its
threshold.

When dissimilar metals are joined a thermocouple effect is
created. Users should select a bidirectional mode to ensure
cancellation of this effect. The instrument measures with
current flowing in both directions and averages the result.

Normal mode is initiated by pressing the ‘Test’ button after
connecting the test leads to the unit under test. Continuity
of all four connections is checked. Current is applied in both
forward and reverse direction following which measurement
is displayed.

Automatic mode is started as soon as the probes make
contact. Forward and reverse current measurements are made
and the average value is displayed. This mode is ideal when
working with handspikes. Each time the probes are removed
and reconnected to the load a new test will be performed
without the need to press the test button.

TEST modes

Automatic unidirectional mode applies current in one
direction only to speed up the measurement process.

However thermal EMF resulting from dissimilar metal bonds
can cause lower accuracy. Test starts automatically when
probes are connected.

Continuous mode allows repeated measurements to be made
on the same sample. Simply connect the test leads and press
the test button. The measurement is updated every three
seconds until the circuit is broken.

Inductive mode is selected when measuring resistance on, for
example, motors and generators. When measuring inductive
loads it is necessary to wait for the voltage to stabilize as the
inductive element is charged. Test leads are firmly connected
to the device under test and the ‘Test’ button pressed. The
instrument will pass the selected current through the sample
continuously in one direction only and take repetitive readings
that will gradually decrease to the true value as the voltage
stabilizes. The operator decides when the result is stable and
presses the ‘Test’ button to terminate the test.

ELECTRICAL SPECIFICATIONS

Resistance/Current Ranges

The green resistance ranges on the keypad indicate low
output power (<0.25 W) outputs. Red ranges indicate higher

2.5 W (1 A) and 25 W (10 A) power outputs.

Resolution and Accuracy

Test current accuracy ±10%

Voltmeter input impedance >200 kΩ

Test
current

Resistance
range

0.1 mA0 to

2500.0 Ω

0.1 mA0 to

250.00 Ω
0 to

1 mA

25.000 Ω
0 to

10 mA

2500.0 mΩ

100 mA0 to

250.00 mΩ
0 to

1 A

25.000 mΩ
0 to

10 A

2500.0 µΩ
0 to

1 A

2500.0 mΩ
0 to

10 A

250.00 mΩ

Resolution
(as
displayed)

0.1 Ω ±0.2% 25 mV

0.01 Ω ±0.2% 25 mV

1 mΩ ±0.2% 25 mV 25 μW

0.1 mΩ ±0.2% 25mV 250 μW

0.01 mΩ ±0.2% 25 mV 2.5 mW

1 μΩ ±0.2% 25 mV 25 mW

0.1 μΩ ±0.2% 25 mV 0.25 W

0.1 mΩ ±0.2% 2.5 V 2.5 W

0.01 mΩ ±0.2% 2.5 V 25 W

Basic
accuracy*

Full
scale
voltage

Max.
power
output

25 μ

W

W

2.5 μ

* The accuracy stated assumes forward and reverse
measurements.

Inductive mode or undirectional mode will introduce an
undefined error if an external EMF is present.

Basic accuracy at reference conditions.

GENERAL SPECIFICATIONS

Temperature coefficient < 0.01% per ºC, from 5 ºC to

40 ºC

Maximum altitude 2000 m (6562 ft) to full safety

specifications

Display size/type Main 5 digit + 2 x 5 digit

secondary displays

Battery type 6 V, 7Ah sealed lead acid

Voltage input range 100 - 240 V 50 / 60 Hz 90 VA

Charge time 8 hours

Backlight LED backlight

Battery life >1000 Auto (3 sec) tests