Megger MOM2 Specifications

MOM2

Micro-ohmmeter

Handheld High Current Micro-ohmmeter

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Up to 240 A

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Bluetooth® headset for audible pass/fail

testing against adjustable limits

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Battery powered

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Handheld, lightweight – 2.2 lb (1 kg)

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Safe test – DualGround

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Auto range: 1 µΩ to 1000 mΩ

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Ultra capacitor technology (patent

™

pending)

MOM2

DESCRIPTION

The MOM2 Micro-ohmmeter is a lightweight, handheld
unit designed to deliver up to 240 Amps and measure the
resistance of circuit breaker contacts, bus-bar joints, and
other high-current links. This product is designed with
safety, ease of use and versatility in mind.

The MOM2 can be used anywhere to measure a low
resistance value with high accuracy. With the MOM2,
it is possible to make measurements according to the
DualGround™ method. This means that the test object will
be grounded on both sides throughout the test giving a
safer, faster and easier workflow.

Its ruggedness and light weight make the MOM2 very
suitable for field work, such as in substations. The unit
comes with a strong rubber holster accessory which makes it
extra durable. The MOM2 is capable of testing for a full day
without recharge. It can store 190 test values and transfer
test data to a PC via Bluetooth.

The Bluetooth feature can also be used in conjunction with
the wireless headset to provide an audible pass/fail signal
against user-adjustable limits as tests are performed.

High Current Generation Using Ultra Capacitor

The MOM2 uses an ultra capacitor to generate the high­output current. Ultra capacitors are able to store huge
amounts of energy compared to conventional capacitors. In
addition, they can deliver very high currents during discharge
as a result of their very low internal resistance.

While testing, the capacitor is discharged through the
test object. The voltage drop across and the current flow
through the test object are continuously and synchronously
sampled. The resistances calculated from the individual
samples are then averaged to obtain the final value.

APPLICATIONS

The MOM2 test system is designed to serve a number of
applications. The most common are contact resistance
measurements of low-, medium- and high-voltage breakers
and also at bus-bar joints, and other high current links.

If the contact resistance is too high, this will lead to power
loss and temperature rise, which often leads to serious
trouble. To avoid such problems, it is necessary to check the
resistance at regular intervals.

The following table demonstrates how important low
resistance is at high currents:

Current Contact resistance Power loss

10 kA 1 mΩ 100 kW

10 kA 0.1 m Ω 10 kW

1 kA 1 mΩ 1 kW

1 kA 0.1 m Ω 100 W

At 10 kA a contact with the resistance 0.1 mΩ gives a
power loss of 10 kW. This power loss in one single point
will definitely confer a temperature rise, which may result in
overheating and possibly premature failure.

MOM2

Handheld High Current Micro-ohmmeter

INSTRUMENT FRONT VIEW

1. Current output terminal (-)

2. Current output terminal (+)

3. Display

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The display offers a combination of analog arc and a

dual digital readout:

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Analog arc:

Indicates level of the capacitor charge.

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Dual digital display:

Large main digital readout for good visibility of all
main measurement results
Second digital display for additional data.

4. Ground (earth) terminal

5. Keys for navigation and to make settings in the display

6. TEST-button

7. Stand-by/Wake up (Press shortly to toggle)

Clear log (Press and hold for 5 seconds)

8. Function selector

OFF

I > I min

I = I max

0.1 s

0.6 s

3 s

0.1 s

0.6 s

3 s

Measurement time with
minimum current guarantee

Measurement time with max. charge

Bluetooth “pair units”

CLK

Set date and time

Set volume for the internal
loudspeaker

SET

Discharge the MOM2 internal
capacitor

PC COM

USER

I min

LOG

P/F

1

2

3

Minimum current guarantee setting
Data log settings
Pass/Fail settings
PC communication

(dump data to PC)

Stored settings. Set from PC,
MOM2Win

9. Connector for the voltage (–) sense lead

10. Connector for the voltage sense (+) lead and the trig

function

11. Connector for the battery charger

12. Battery charger indicator

9 10

1 2

3

4

5

6

7

8

11

12

4 wire Kelvin test

The Kelvin probes (included in BD-59090) are used for a 4-wire Kelvin
test. This is a way of measuring continuity resistances ensuring all
contact and lead resistances are compensated for, allowing a much
greater accuracy in measurements. Each Kelvin probe assembly has two
probe tips: one tip is for the current generated; the other will measure
the very small voltage present.
The Kelvin clamps (included in BD-59092) use the same principle.

The "double" probe tip showing the springy center tip

MOM2

Handheld High Current Micro-ohmmeter

APPLICATION EXAMPLES

Circuit Breaker testing

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Test of circuit breaker contacts

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Test of the connections to the breaker

Testing of Bus-bar

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Test of Bus-bar joints

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Test of connections

Everywhere you need to test a low resistance/
high current connection

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Switches

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Disconnecting devices

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Safety ground connections

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Welding points

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Fuses

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Cables

BOTH SIDES GROUNDED

Within electrical power utilities, switchgear owners and
service companies, there is an increased emphasis on
efficiency of operations, maintenance and service levels.
There is an increased emphasis on health, safety, and
environmental compliance. Experience has also shown
demands for shorter time periods for testing, while the
switchgear is less and less available to be taken out of
service.

Many utilities require safety grounds to remain in place
during station outages, and the MOM2 was designed with
this field safety constraint in mind. DualGround means that
the test object will be grounded on both sides throughout
the test giving a safer, faster and easier workflow. Minimum
time is spent in the substation and focus is on the test rather
than the equipment.

Conventional vs. DualGround

Site preparation (isolate work
area, apply safety ground, issue
permit to work)

Hook up test equipment. Issue
sanction for test

Authorized person removes the
ground

Perform testing Safe testing with both sides

Authorized person applies
ground

Cancel sanction for test.
Disconnect test equipment

Site closing (cancel permit to
work, disconnect ground)

Site preparation (isolate work
area, apply safety ground, issue
permit to work)

Hook up test equipment. Issue
sanction for test

Risky step left out

grounded
Risky step left out

Cancel sanction for test.
Disconnect test equipment

Site closing (cancel permit to
work, disconnect ground)

Hold probes / attach Kelvin clamps to CB and press trig / TEST button.
A signal indicates whether test was pass or fail and result is logged in
unit for later dump to PC.

Traditional measurement from ground. Injection is done through
existing grounding cable (earthing). Optional cable kit is needed.
Available kits have 5, 10 or 15 m cables.

Equipment and methods that supports
DualGround™ testing are associated with the
DualGround symbol. This symbol certifies the use
of groundbreaking technology and methods that
enables a safe, fast and easy workflow with both
sides grounded throughout the test.

Measurement on CB with both sides grounded, DualGround.

MOM2

Handheld High Current Micro-ohmmeter

SPECIFICATIONS

Specifications are valid at fully charged batteries and an ambient
temperature of +25°C, (77°F). Specifications are subject to change
without notice.

Environment

Application field For use in high-voltage substations

and industrial environments.
Temperature
Operation* -20ºC to +50°C (-4°F to +122°F)
Storage -40ºC to +70ºC (-40°F to +158°F)
Relative humidity %RH 5%-95%, non condensing
Pollution degree 2
Shock IEC 60068-2-27
Vibration IEC 60068-2-6
Transport ISTA 2A
*Battery operation temperature 0ºC to +50° (32°F to +122°F)

*Battery charging temperature +10ºC to +40° (50°F to +104°F)

General

Battery power Five AA (HR6) 2700 mAh NiMH cells
Recharge time < 12 h

Typical recharge time at
25°C

Battery charger
Mains voltage 100 - 250 V AC, 50 / 60Hz
Power consumption 60 W
Protection Against wrong battery type, low/high

Real time clock battery life ≥10 years
Audible feedback Different buzzer sounds
User presets 3
Field calibration Yes
Encapsulation IP54
Dimensions

(excl. binding posts)
Weight 2.2 lbs (1.0 kg) instrument only

CE-marking

EMC 2004/108/EC
LVD 2006/95/EC

3 h

temperature

217 x 104 x 72 mm

8.5 x 4.1 x 2.8 in.

11 lbs (5.0 kg) with accessories and

carrying case

Outputs + / –

Range > 100 A DC (R < 2 mΩ)
Output voltage (max) 2.5 V DC
Generation duration Selectable: 0.1 s, 0.6 s, 3 s

Recovery time at I min set to 100 A
and load 100 μΩ

Generation time Max Typ

0.1 s 10 s 8 s

0.6 s 20 s 16 s
3 s 130

s

Inputs

SENSE + / –

Connector 4 mm banana jack
Voltage ±3 V DC

Trigger input Threshold 8 V DC
DC IN 12 – 24 V DC, 2 A max

Logger

Logger, Data Label. Timestamp, I max, I min, I Limit,

Resistance, Meas.time, P/F limit

Labeling schemes Circuit breaker oriented or diary

number

Capacity 190 measurements

Wireless communication

Headset Bluetooth
PC communication Bluetooth

100 s

INCLUDED ACCESSORIES

Measurement section

Minimum current
guarantee

Pass / Fail Settable from 1 µΩ to 1999 mΩ
Number of measurements

on fully charged batteries
Interference suppression Yes
Range 0 - 1000 mΩ
Range selection Auto
Resolution
0 – 999 µΩ 1 µΩ

1.0 – 9.99 mΩ 0.01 mΩ

10.0 – 99.9 mΩ 0.1 mΩ
100 – 1000 mΩ 1 mΩ
Accuracy
0 – 1999 µΩ ±1 % of reading ±1 digit
2 – 1000 mΩ ±2 % of reading ±1 digit

Selectable 50 A / 100 A

Valid at resistance ≤2mΩ

typ. 2200 at I min = 50 A and 0.1 s

typ. 800 at I min = 100 A and 0.1 s

MOM2 shown with transport case, charger, rubber holster, carrying
strap, belt clip, MOM2 Win software.

Kelvin probes (incl. in BD-59090)

MOM2

MOM2

Handheld High Current Micro-ohmmeter

Handheld High Current Micro-ohmmeter

OPTIONAL ACCESSORIES

Bluetooth headset

Calibration kit

Connection plate, used with the
cable kits

Bluetooth dongle

Soft carrying case

ORDERING INFORMATION

Item Cat. No.

MOM2 Micro-ohmmeter including:
2 x 1.3 m (4 ft) test cables Kelvin probes
(one with trig button) transport case,
charger, rubber holster, carrying strap,
belt clip, MOM2 Win

MOM2 Micro-ohmmeter including:

1.3 m (4 ft) test cable red with Kelvin clamp
3 m (10 ft) test cable black with Kelvin clamp,
transport case, charger, rubber holster,
carrying strap, belt clip, MOM2 Win

MOM2 Micro-ohmmeter including:

1.3 m (4 ft) test cable red with Kelvin clamp
5 m (16 ft) test cable black with Kelvin clamp,
transport case, charger, rubber holster,
carrying strap, belt clip, MOM2 Win

Optional Accessories

Test cables with Kelvin probes 2 x 1.3 m (4 ft)
(one with trig button)

Test cables with Kelvin clamps 1.3 m (4 ft) red,
3 m (10 ft) black

Test cables with Kelvin clamps 3 m (10 ft) black GA-00372

Test cables with Kelvin clamps 1.3 m (4 ft)
black, 16 mm

2

Test cables with Kelvin clamps 5 m (16 ft) black GA-00374

Test cables with Kelvin clamps 10 m (33 ft)
black, 16 mm

2

Cable kit 5 m
Current cable 0.5 m (1.6 ft), connection plate
and sense cables 5 m (16 ft), ground cable

Cable kit 10 m
Current cable 0.5 m (1.6 ft), connection plate
and sense cables 10 m (33 ft), ground cable

Cable kit 15 m
Current cable 0.5 m (1.6 ft), connection plate
and sense cables 15 m (49 ft), ground cable

Bluetooth headset and dongle for PC XC-06000

Calibration kit BD-90002

Soft carrying case for MOM2, charger & cables GD-00620

BD-59090

BD-59092

BD-59093

GA-90000

GA-90001

GA-00373

GA-00376

GA-00380

GA-00382

GA-00384

UNITED STATES

Megger
2621 Van Buren Avenue
Norristown, PA 19403 USA
T [phone]
T [phone]
F [phone]

SWEDEN

Megger Sweden AB
Rinkebyvägen 19
SE-182 36 DANDERYDT
[phone]
F [phone]
E [e-mail]

Other Technical Sales Offices

Dover UK, Dallas USA, College Station
USA, Sydney AUSTRALIA, Ontario CANADA,
Trappes FRANCE, Oberursel GERMANY,
Aargau SWITZERLAND, Dubai UAE, Mumbai
INDIA, Johannesburg SOUTH AFRICA, and
Chonburi THAILAND

Registered to ISO 9001 and 14001
Subject to change without notice.

MOM2_DS_US_V15

www.megger.com
Megger is a registered trademark