Doble M4100 Insulation Analyzer

Buy or Rent the Doble M4100 Power Factor tester. Fully automated “intelligent” testing means you get reliable answers, not just data.

  • Measures power factor/tangent delta and capacitance
  • Performs various diagnostic tests (power factor, capacitance, turns ratio, etc.)
  • Outputs 300 mA at 10 kV with high charging current
  • Internal waveform generator for precise sine wave
  • Fully digital internal measurement circuitry
  • Patented Line Frequency Modulation technology
  • Includes M4000 software for easy test management
  • Rugged construction and self-calibrating in the field
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Product Overview: Doble M4100 Insulation Analyzer

Doble M4100


The world’s most advanced test system for power apparatus diagnostics

The M4100 is the leading instrument for evaluating the condition of high-voltage power apparatus. It sets the standard for accuracy, reliable test results, and intelligent diagnostics for customers worldwide. The M4100 was engineered from the ground up to overcome the common problems that plague other test instruments.

The instrument evaluates the integrity of high-voltage substation apparatus by measuring the power factor/tangent delta and a number of other values. It also measures capacitance, to evaluate physical changes to the apparatus.

The M4100 allows you to perform a variety of diagnostic tests:

  • Power Factor testing to confirm insulation integrity and quality
  • Capacitance testing to measure physical changes that may have occurred to the apparatus
  • Turns Ratio testing to detect shorted turns or winding damage
  • Leakage Reactance/Short Circuit Impedance testing to evaluate winding deformation
  • Single Phase Excitation Current testing to evaluate the transformer’s magnetizing circuit

With a maximum output of 300 mA at 10 kV, the M4100 offers high charging current, allowing you to run single-phase exciting current tests at higher voltages, increasing the turn-to-turn stress. The M4100 has the power to test a wide range of apparatus, making it highly versatile. If you need more current than 300 mA for large apparatus, the Type C Resonator option extends the range. If you need higher voltage than 12 kV, the M4120 External Reference Module option allows you to use a power supply other than Doble’s and adapt to any international standard.

The accuracy of test results is directly related to the quality of the test signal. While most test instruments use available power lines or portable generators to generate the output test signal, the Doble M4100 uses an internal waveform generator to create its own precise sine wave. This produces reliable results and stable readings. The quality of the power source is not an issue.

The internal measurement circuitry is fully digital. Unlike other test instruments, the M4100 eliminates the need to balance the bridge, automatically making measurements for you.

The M4100 also uses a patented technique called Line Frequency Modulation, in which measurements are made at a frequency above and below the system frequency, to eliminate the effect of electrostatic interference. The result is highly accurate and repeatable measurements. Even a small change in a measurement becomes a reliable diagnostic indicator.

The Doble M4100 instrument comes with M4000 software to simplify the management of test results. It also offers a range of built-in self-diagnostic tools.

Doble M4151 Field Calibration Reference Module

The M4151 Field Calibration Reference Module, which comes standard with the M4100, allows you to verify the instrument’s calibration in the field.

Liquid-Insulation Cell

The Liquid-Insulation Cell (Oil Cell), also supplied with the M4100, can be used in the field for a quick accuracy check.

Features and Benefits

  • Doble’s patented Line Frequency Modulation technology eliminates substation signal interference.
  • Generates its own clean test signal for the most reliable and repeatable results.
  • Provides the highest power to better replicate in-service conditions.
  • Self-calibrating in the field, so it’s always accurate.
  • Advanced digital technology takes accuracy to new levels.
  • Automated setup eliminates errors.
  • M4000 software makes testing easy, fast, and smart.
  • Records are presented in a format that is easy to read, save, and print.
  • Built-in test set diagnostics provide information on instrument status.
  • Rugged construction provides the accuracy of a laboratory instrument with the ability to withstand harsh field conditions.


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JM Test Rental options can help you save capital, get the latest technology, and expand your capabilities. Daily, Weekly and Monthly rates are available on select items.