LRM 200

True DC Micro Ohmmeter

  • Continuous 0 – 200 A DC output
  • Full-size keyboard, Touch enabled color display and built-in thermal printer
  • Dual grounding option for enhanced safety
  • Internal Storage of 150 test records with up to 75 readings
  • Ability to export test results to PDF and Excel format
  • Settable rise and fall time of test current to avoid maloperation of associated relays
  • Field portable rugged housing


The LRM 200 is a microprocessor-based, true DC microohmmeter designed to test the contact resistance of circuit breaker contacts, switchgear, and bus bar joints. It is the instrument every test technician needs to have to maintain circuit breakers, switch gear and busbars. The LRM 200 is designed to meet the IEEE C57.09-1999 standard’s requirements for testing circuit breaker contact resistance.

The LRM 200’s wide measuring range is 1 micro Ohm to 5 Ohms with 0.1 micro-ohm resolution with a current range of 10 A to 200 A. The LRM 200 injects a true DC current through the contacts under test and measures the contact resistance.

Dual Ground Mode Test:

Typically during this test, only one end of the Circuit breaker is grounded for accurate measurement. The LRM 200 can perform CB testing in Dual Ground mode. In Dual Ground mode, both sides of the circuit breaker are grounded. Some current is diverted to the ground via a ground cable. An external current sensor connected to the ground cable provides input to the LRM 200 which eliminates the effect of the diverted current and produces accurate results. The LRM 200 then calculates the actual resistance value of the circuit breaker main contact.

As the rise and fall time is configurable for each test, no transients are induced in the associated apparatus such as current transformers. This avoids maloperation of the connected relays to the current transformers.

User Interface

The unit’s back-lit color LCD touchscreen (800 x 480 pixels) is
viewable in bright sunlight and low-light and provides an intuitive menu structure where running a test is just few taps away.
The full-sized industrial keyboard makes data entry quite easy
for information such as nameplate and setting information

Test Records and Built-in Thermal Printer

The internal memory of the LRM 200 can store up to 150 records of 75 readings each. These results can be transferred to a USB flash drive or to a computer directly via the USB PC interface. The LRM200 features a built-in 2.0” thermal printer for quick printout of results in the field. 

Technical Specifications : LRM 200

Input Power
Operating Voltage
90 ¬ 240 Vac, 50/60 Hz
Measuring Method
IEEE C57.09-1999
Typical Accuracy
±(0.15% of reading + 0.15% FS) at test current of 10¬200 A
0.1 μΩ ¬ 999.9 μΩ: 0.1 μΩ
1.000 mΩ ¬ 9.999 mΩ: 1 μΩ
10.00 mΩ ¬ 99.99 mΩ: 10 μΩ
100.0 mΩ ¬ 999.9 mΩ: 0.1 mΩ
Built-in 2″ wide thermal printer
Display & keyboard
Color touch-screen LCD (800 x 480 pixels) & “QWERTY”-style keyboard
Computer Interface & software
One USB PC interface for downloading test records and generate report via USB 2.0
Internal Test Record Storage
Up to 150 records with max 75 results per record (8,000 test records)
External Test Record Storage
USB Flash drive interface to copy test records and firmware updates
Operating/Storage Temparature
Operating: -10°C to +50°C (+15°F to +122°F) Storage: -30°C to +70°C (-22°F to +158°F)
90% RH @ +40°C (+104°F)
Physical Specifications
18”W x 7”H x 15” D (45.7 cm x 17.8 cm x 38.1 cm)
25 Lbs. (11.3 Kgs)
Test Cables
2 x 30’(10 m) high current cable , 2 x 30’ (10 m) voltage sense cable, power cord, USB cable, 10’ ground cable and one cable bag
2 years on parts and labor
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