MJÖLNER 600

Microhmmeter

MJÖLNER 600
Microhmmeter

▪▪Fullyautomatic testing – Micro processor

controlled

▪▪Safe test – DualGround™ and Remote

control

▪▪True DC – ripple free current

▪▪Lightweight suitcase – withstands the

impact of water, dust or sand

▪▪Built in thermal printer

▪▪PC interface connection

Description Applications
The MJÖLNER™600 is designed to measure the resistance of MJÖLNER 600 test system is designed to serve a number
circuit breaker contacts, bus-bar joints, contact elements in bus- of applications. The most common are contact resistance
bars and other high-current links. The product has been designed measurements of low-, medium- and high-voltage breakers and
with safety, ease of use and versatility in mind. also at bus-bar joints, and other high current links.
The microhmmeter conducts true DC ripple free current and The contact resistance measurements concerning breaker testing
can be used anywhere to measure a low resistance value with are particularly called for in the following standards:
high accuracy. With MJÖLNER 600 it is possible to make ANSI C37.09-1979 (5.14), IEC 1208 and IEC 694 (6.4).
measurements according to the DualGround™ method. This If the contact resistance is too high this will lead to power loss and
means that the test object will be grounded on both sides temperature rise, which often leads to serious trouble. To avoid
throughout the test giving a safer, faster and easier workflow. such problems, it is necessary to check the resistance at regular
Choose the MJÖLNER 600 with excessive power resources for intervals.
demanding applications, superior measurement accuracy and when The following table demonstrates how important low resistance is
300 Amp continuous is required. at high currents:
The lightweight and rugged suitcase design makes MJÖLNER 600
an excellent choice when you need a portable solution in the field. Current Contact resistance Power loss
When the case is closed, the product can withstand the impact of 10 kA 1 mΩ 100 kW
water, dust or sand – it even floats. 10 kA 0.1 mΩ 10 kW
Two optional accessories are; a remote control and the PC 1 kA 1 mΩ 1 kW
software MJÖLNER Win that is compatible with IPS–CBEX and 1 kA 0.1 mΩ 100 W
have export functions for tables to Microsoft® Excel®.
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.
 MJÖLNER 600
Microhmmeter
Features and benefits
1. Grounding terminal 15. Internal memory.
2. Connection and switch for mains voltage ▪▪Store up to 100 measurements during field tests and later recall
3. Temperature sensor input these results via the built in display.
4. USB port 16. Error LED
▪▪Lit when the adjusted current could not be reached
5. Remote control connector
17. Start/Stop key with status LED
6. DC+ current output
▪▪Quick-lock cable connection 18. Status LED’s
▪▪True DC current — no risk of unintentional tripping of relays ▪▪Indicating the actual measuring status
▪▪Output protection by thermal sensors + software – enables the 19. Suitcase shape
user to make maximum use of the high current capability of ▪▪The unit comes close to the body thus making the unit easier
the instrument without risk of damage to carry.
7. Sensing terminals ▪▪Rugged plastic housing, in most cases no need for an additional
▪▪Wide measuring range, from 0.1 mΩ to 1 Ω heavy transport case.
8. DC – current output 20. Current cables in separate bag
▪▪Quick-lock cable connection ▪▪Perfect balance when carrying the equipment.
9. Displays, LCD and LED
▪▪Direct ohm reading at any current.
▪▪Accuracy is not affected by adjustment of the current to a
specified value.
▪▪Visible results in all light conditions — one LCD and one LED
10. Shunt output
▪▪Calibration shunt that enables the user to quickly verify the ac-
curacy of the instrument, in the field.
11. Adjustment keys
▪▪To set the measuring current and all menu values
12. DC current clamp sense input
13. Printer
▪▪Fast printing of all test results.
14. Keys to control the menu functions
▪▪Currents can be set from 5 to 600 A.

20

1
6

2
7

9
3
10
4
11
5 12

13 14 15 16 17 18 19
 MJÖLNER 600
Microhmmeter
Application examples Both Sides Grounded
Circuit Breaker testing Many utilities require safety grounds remain in place during station
outages, therefore, the MJÖLNER 600 was designed with this field
Test
▪▪ of circuit breaker contacts
safety constraint in mind.
Test
▪▪ of the connections to the breaker
Minimum time shall be spent in the substation and focus shall be
Testing of Bus-bar on the test rather than the equipment.
Test
▪▪ of Bus-bar joints
The DualGround™ testing method is available for all tests on
Test
▪▪ of connections all circuit breakers. The following table indicates the Megger
Transformer testing instruments that the MJÖLNER 600 works in conjunction with:
Winding
▪▪ resistance – not on all type of transformers. Timing TM1800 with DCM module
(In many transformers there is a need for higher voltage Motion TM 1800
than 5 V)
Dynamic Resistance TM 1800 with SDRM202
Internal/external
▪▪ connections Measurement (DRM)
Everywhere you need to test a low resistance/ Vibration CABA Win Vibration
high current connection
Switches
▪▪

Disconnecting
▪▪ devices
Safety
▪▪ ground connections
Welding
▪▪ points
Equipment and methods that supports DualGround™ test-
Fuses
▪▪
ing are associated with the DualGround symbol. This symbol
Cables
▪▪ certifies the use of groundbreaking technology and methods that
enables a safe, fast and easy workflow with both sides grounded
throughout the test.

Using an external voltmeter, measure the voltage drop (voltage) You can make tests with both sides of the test object grounded,
across each contact element within every section of the bus-bar an additional safety feature.
being tested.
 MJÖLNER 600
Microhmmeter
Specifications
Specifications are valid at nominal input voltage 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 -20 to +50°C (-4°F to +122°F)
Storage -40ºC to +70ºC (-40°F to +158°F)
Relative humidity %RH 5%-95%, non condensing
CE-marking
EMC 2004/108/EC
LVD 2006/95/EC
General
Mains voltage 100 - 120, 200 - 240 V AC, 50 / 60 Hz
Power consumption (max) 39 A at 100 V, 18 A at 230 V
Protection Thermal fuses, Software
Dimensions 486 x 392 x 192 mm
(19” x 15.4” x 7.6”)
Weight 13.8 kg (30.4 lbs)
Measurement section
Measuring range 0 – 999.9 mΩ
Resolution 0.1 μΩ below 1.0 mΩ
1 μΩ below 10 mΩ
10 μΩ below 100 mΩ
100 μΩ below 1000 mΩ
Inaccuracy, 50 – 600 A, Typ ±0.3 μΩ, Max. ±2 μΩ
ta 10 - 40ºC, R < 1 mΩ
Outputs
DC+ / COM
Range 5 – 600 A DC (steps of 1 A)
Output voltage (max) 5.25 V DC at 600 A
OUTPUT 100 μV/A
Shunt output From internal shunt 60 mV at 600 A
Inaccuracy ±1%
Inputs
SENSE Max. 20 V between terminals and
to protective earth (ground).
INPUT DC current Max. 20 V between terminals and
clamp to protective earth (ground).
Input sensitivity Adjustable 0.1 – 20 mV/A
Input impedance >1 MΩ
 MJÖLNER 600
Microhmmeter
Optional accessories

MJÖLNER Win

The Windows program makes it easy to manage/save all test

results in a simple way. All information, meta-data of the test
object e.g. a circuit breaker and the test results are stored together
and they can easily be transferred to Microsoft® Excel for further
analysis.
Ordering information
Remote control Item Art. No.
MJÖLNER 600
Incl. Std. cable set 3 m, (current cables 2 x 3 m,
35 mm2 and sensing cables 2 x 3 m), Ground cable BB-59090
Incl. Std. cable set 5 m, (current cables 2 x 5 m,
35 mm2 and sensing cables 2 x 5 m), Ground cable BB-59091
Incl. Std. cable set 3 m, (current cables 2 x 3 m,
35 mm2 and sensing cables 2 x 3 m), Ground cable
and DC Current clamp (200 A / 20 mV) BB-59092
Optional accessories
MJÖLNER Win
Windows® software BD-8010X
Remote control BD-90010
Temperature probe BD-90012
Thermal paper roll (for printer) GC-00050
Extension cable set 5 m
(current cables 2 x 5 m, 35 mm2
and sensing cables 2 x 8 m) GA-03206
Extension cable set 10 m
Many times, you place the test equipment on the ground while (current cables 2 x 10 m, 35 mm2
the cables are connected high up on a circuit breaker. In these and sensing cables 2 x 13 m) GA-03208
situations, it can save a lot of time using a remote control during Calibration kit
the test. The remote control has most of the functionality in the 200 A / 20 mV shunt and instruction BD-90022
MJÖLNER 600 such as starting and stopping, setting the test DualGround kit
current and read out the test values DC Current clamp 200 A (incl. cables) XA-12792

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