The MMR-630 Series microohmmeters are professional-grade, portable instruments for measuring very low resistances. Due to their special measurement algorithms they can be used to test both resistive and inductive objects.The MMR-630 is designed for electricians to test many types of electrical junctions, motor and power transformer windings. The results can be stored in the internal memory and sent to a computer via serial to USB interface. A PASS/FAIL test function rapidly displays results and indicates test progress with audio tones to give feedback to the user, and simplify the measurements.
- Technical specification
- Measurement of resistive objects:
- welded and soldered connections, equipotential bonding, earth wire connections,
- terminals and connectors, welded joints, cables and wires,
- measurement by 4-pole method.
- Measurement of inductive objects:
- coils and windings (motors and transformers), low resistance coils.
- Range selection autoranging or manual (for measurement of inductive objects).
- Selectable measurement mode adjusted to object type:
- for resistive objects - fast mode (3 seconds),
- for inductive objects - long mode with automatic discharge after measurements (or with lower accuracy - shorter mode).
- Selectable measurement mode adjusted to application:
- normal mode - after pushing ”START” button,
- automatic mode - when test leads are connected to the object the meter automatically starts measurement with dual direction current flow, and gives average result - dual direction flow eliminates residual DC voltage remaining on tested object.
- continuous mode - every 3 seconds for resistive objects, or continuous for inductive objects.
- Window mode:
- this option enables setting an upper and a lower limit between which the average measurement result appears. Results outside of this range are indicated by two long audio tones and warning symbols.
- MMR-630 is immune to interference up to 20 mV, and will show noise from 20 to 100 mV (so in edge conditions this is 5 times higher than the measured voltage potential drop).
- Memory storage for up to 990 results
- Serial to USB adapter to transfer data from to a PC
- double-insulated, according to EN 61010 - 1 and IEC 61557
- measurement category: CAT III 300 V acc. to EN 61010 - 1
- enclosue protection class acc. to EN 60529: IP54
Other technical data:
- power supply: battery package SONEL/Ni-MH 4.8 V
- battery charging time: approx. 2.5 hours
- number of measurements with a current of 10 A: 300
- auto-off time: 120 seconds
- immunity to interference: additional error ≤1% for voltage 60 Hz ≤100 mV RMS
- maximum test lead resistance for 10 A current: 0.1 Ω
- maximum inductance of the tested object: 40H
- accuracy of the test current: ±10%
- resistance measurement time:
with resistive object type and bidirectional current: 3 seconds
with the selected inductive object type, dependent on the resistance and inductance of the object: max. 10 minutes
- dimensions: 11.61" x 8.74" x 3.74" / 295 x 222 x 95 mm
- weight: approx. 3.75 lbs / 1,7 kg
Rated operational conditions:
- operating temperature: 32F to 104F / 0 to +40°C
- storage temperature: -4F to 140F / -20 to +60°C
MMR-620 microohmmeter conforms the following directives or standards according to CE requirements.
Low Voltage Directive (LVD) 73/23/EEC, 93/68/EEC.
EN 61010 - 1:2001 Safety requirements for electrical equipment for measurement, control and laboratory use. General requirements .
EN 61010 - 031:2002: Safety requirements for electrical equipment for measurement, control and laboratory use. Safety requirements for hand-held probe assemblies for electrical measurement and test.
Electromagnetic compatibility (EMC) 89/336/EEC, 92/31/EEC, 93/68/EEC.
EN 61326:1997+A1:1998+A2:2001 Electrical equipment for measurement, control and laboratory use - EMC requirements.
MMR-630 Current Accuracy Range Resolution 0 to 999.9μΩ 0.1μΩ 10 A ±(0.25% m.v. + 2 digits) 1.0000 to 1.9999 mΩ 0.0001 mΩ 2.000 to 19.999 mΩ 0.001 mΩ 20.00 to 199.99 mΩ 0.01 mΩ 1 A 200.0 to 999.9 mΩ 0.1 mΩ 0.1 A 1.0000 to 1.9999 Ω 0.0001 Ω 2.000 to 19.999 Ω 0.001 Ω 10 mA 20.00 to 199.99 Ω 0.01 Ω 0.1 mA 200.0 to 1,999.9 Ω 0.1 Ω 0.1 mA
- input impedance of the voltmeter: ≥200 kΩ
”m.v.” - measured value.
- Measurement of resistive objects: