MO-2Ke digital milli ohmmeter

What is a milliohmmeter used for?

Low resistances — contact resistances of switches and power relays, winding resistances of motors and transformers, busbar joints and cable connectors — fall in the range of milliohms to a few ohms. A standard multimeter is not accurate enough for these measurements: the resistance of the test leads alone introduces significant errors. The MO-2Ke uses the four-wire Kelvin measurement method with separate current and voltage leads, fully eliminating lead and contact resistances from the measurement result.

Four test currents, four ranges

The test current is continuously adjustable per range from 0 to 100% of the nominal value:

• 1 A — range 0–2 Ω, resolution 0.01 mΩ
• 100 mA — range 0–20 Ω
• 10 mA — range 0–200 Ω
• 1 mA — range 0–2,000 Ω

The open-circuit output voltage reaches up to 10 V DC (at 1 A), which reduces stabilisation time when testing highly inductive components such as transformer windings. The set test current is displayed as an analogue bargraph on the screen — useful for precise current adjustment when measuring inductive loads. The measurement circuit is protected against voltage spikes generated by inductances.

Display, HOLD function and accuracy

The alphanumeric display shows measurement values with up to 4½-digit resolution — direct reading without conversion. The HOLD function freezes the measured value on screen, convenient when measuring in hard-to-reach locations. Basic accuracy is ±0.2% of reading ±2 digits, guaranteed by an offset-free signal amplification system with long-term stability.

RS232 output and data logging

The MO-2Ke features a serial RS232 output (4,800 bps) for downloading measured values to an external serial printer, laptop, or data logger. This enables test series to be recorded and archived without manual entry. An optional built-in thermal printer is available for direct on-site hardcopy output.

Battery and field use

The MO-2Ke is equipped with a built-in rechargeable battery of 12 V / 3,000 mAh, rechargeable via the built-in charger from 100–240 V AC. With IP65 protection (lid closed), the instrument is suitable for outdoor use under harsh weather conditions. Weight approximately 3 kg, dimensions 274 × 250 × 124 mm including carrying case.

Applications

• Contact resistance measurement on power circuit breakers, vacuum switches and relays
• Winding resistance measurement on motors, generators and transformers
• Measurement of busbar connections, cable terminals and welded joints
• Quality control of electrical connections in production and maintenance
• Periodic inspections in accordance with IEC and IEEE maintenance standards

Why order through IONIO?

IONIO supplies the MO-2Ke including a factory calibration certificate and offers periodic calibration services. You will automatically receive a reminder six weeks before your calibration interval expires. For questions about the correct test current for your application or about the optional built-in printer, you can schedule a consultation directly.

Technical specifications