Index: WMGBMMR630
Low resistance meter
Technical Specification
  • Description

    Measure motor winding resistance and other low resistances

    Perform precise tests of objects of resistive and inductive nature using one instrument - small resistance meter Sonel MMR-630.

    We present a versatile small resistance meter that provides very high measurement accuracy. The measurement resolution is 0.1 µΩ. The MMR-630 model enables measurements of objects of resistive as well as inductive nature, such as transformers and motors. This is due to the large measurement current for the individual subranges and the corresponding operating modes. When testing objects of a resistive nature, rapid measurement (3 seconds) is applicable. When testing inductive objects, extended measurement is used (there is also the possibility of a shortened mode with a slightly lower measurement accuracy).

    The MMR-630 has been enhanced with special functions that allow it to be used also in the production cycle for serial measurements, for example, during the inspection of large batches.


    Product features

    MMR-630 microohmmeter enables accurate measurements of both connections resistance (welded, soldered, bolted) and winding resistance of electrical motors and power transformers.

    • Measurements of objects resistive in nature:
      • welded and soldered connections, equipotential bondings, earthing conductors,
      • contacts, welds of rails, conductors and cables,
      • measurement according to the four-lead method.
    • Measurements of objects inductive in nature:
      • motor windings,
      • low-resistance coils.

    Additional functions

    • Automatic or manual selection of measuring range (measurement of objects of an inductive nature).
    • Selection of measurement mode according to the type of measured object:
      • fast measurement (3 seconds) for measurement of objects of a resistive nature,
      • extended measurement for testing of objects of an inductive nature (accelerated mode, with slightly worse accuracy, available); with automatic discharging of the object after measurement.
    • Selection of measurement mode depending on application (including control of product series):
      • measurement in normal mode - triggered when the “START” button is pressed,
      • measurement in automatic mode - the instrument awaits connection of all four test leads to the object, after which it automatically start measurement in one or both directions and calculates the mean resistance value,
      • measurement in continuous mode - the meter repeats successive measurement cycles with breaks every 3 seconds (for objects of a resistive nature) or performs measurement continuously (for objects of an inductive nature)
    • Window mode:
      • makes possible to set an upper and lower limit within the measurement result should remain; sound signal triggered when the result is beyond set range,
      • capability of performing measurements even under disturbances of a value five times greater than the measured signal.
  • Technical Specification

    Resistance measurement

    Range Resolution Test current Accuracy
    0...999 μΩ 1 μΩ 10 A ±(0.25% m.v. + 2 digits)
    1.0000...1.9999 mΩ 0.0001 mΩ 10 A ±(0.25% m.v. + 2 digits)
    2.000...19.999 mΩ 0.001 mΩ 10 A ±(0.25% m.v. + 2 digits)
    20.0...199.9 mΩ 0.01 mΩ 1 A ±(0.25% m.v. + 2 digits)
    200...999.9 mΩ 0.1 mΩ 0.1 A ±(0.25% m.v. + 2 digits)
    1.0000...1.9999 Ω 0.0001 Ω 0.1 A ±(0.25% m.v. + 2 digits)
    2.000...19.999 Ω 0.001 Ω 10 mA ±(0.25% m.v. + 2 digits)
    20.00...199.99 Ω 0.01 Ω 1 mA ±(0.25% m.v. + 2 digits)
    200...1999 Ω 0.1 Ω 0.1 mA ±(0.25% m.v. + 2 digits)

    m.v. - measured value

  • Files