MO-5889-200A Portable Digital Micro-ohmmeter


  • Microprocessor controlled
  • Alphanumerical display
  • Resolution: 0.1 μΩ
  • Resistance reading: up to 20 mΩ
  • Up to 200 A test current
  • Kelvin-type (4-Wires) measurement
  • Internal memory for up to 200 readings
  • Direct reading (up to 4½ digits)
  • Overheating protection
  • USB interface
  • Built-in printer

For more information contact Tinsley

Download our data sheet

The MO-5889-200A high-current micro-ohmmeter is a portable, microprocessor-controlled instrument. Has optimized filters and protections for measurements in electrical substations. Can be used to accurately measure very low contact resistances of high voltage circuit-breakers and switches, busbars, etc., with test currents up to 200 A. It employs the 4 terminals-method (U/I measuring principle) to avoid errors caused by test leads and their contact resistances.

Measurement accuracy is guaranteed by a state-of-the-arts signal amplification system, offset-free and of high long-term stability. Resistances readings are shown in the alphanumeric display with up to 4½ digits-resolution. It allows to measure resistances up to 20 mΩ, and the best resolution is 0.1 μΩ.

Test current may be adjusted by the operator and his value is measured using an analog indicator (bargraph). It has an internal memory for up to 200 readings. The USB interface may be connected to a computer to download the stored values.

The high-current generation system is based on modern technology that allows to significantly decrease both its weight (approx. 24.25 lb | 11 kg) and size.

The cabinet is made of plastic material highly resistant to impacts and to environmental challenges. Internal thermal sensors in all sensitive components avoid any damage caused to the instrument due to overheating.

This is strong but lightweight equipment, and may be easily carried by one person. It is water-resistant and can be used under severe weather conditions (IP65 with closed lid) offering an excellent performance working both in the laboratory and out in the field.

Test current
Up to 100 A, 200 A (True DC).
The current may be continuously adjustable from 0 to 100%.

Resistance ranges
0-1999 μΩ (test current: up to 200 A).
0-19.99 mΩ (test current: up to 100 A)

Reading resolution
0.1 μΩ for R < 2000 μΩ.
1 μΩ for R < 20 mΩ.

Output voltage
3.5 VDC @ 200 A.
4.5 VDC @ 100 A.
5.8 VDC (without load).

Maximum load resistance
10 mΩ @ 200 A.
30 mΩ @ 100 A.

Measurement principle
Four-terminal, U/I.

Thermal protection
Protects all sensitive components, avoiding any damage due to overheating.

Continuous operation time
At 200 A this equipment may be used continuously for approx. 1 minute before the thermal protection activates.
At 100 A this equipment may be used continuously for approx. 15 minutes before the thermal protection activates.

Basic accuracy
± 0.5 % of reading ± 2 digits.

Advanced features
Digital direct reading of very low resistances in the alphanumerical display, with up to 4½ digits. Very fast and accurate measurements.

Built-in memory
It allows the storage of 200 tests readings.


Environmental protection
IP65 (with closed lid).

Safety class
Meets the requirements of IEC 61010-1.

Power supply
Mains: 220-240 V~.

Operating temperature range
23 °F to 122 °F (-5 °C to 50 °C).

Storage temperature range
-13 °F to 158 °F (-25 °C to 70 °C).

Humidity range
95 % RH (non condensing).

Equipment weight
Approx. 24.25 lb (11 kg).

19.76" x 15.51" x 7.48" (502 x 394 x 190 mm).

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