10 A leakage reactance tester

  • Measures the short circuit impedance of transformers
  • Useful in detecting and diagnosing winding deformation
  • Capable of performing measurements in single- or three-phase transformers
  • Optional capacitor bank testing

The MLR10 10 A leakage reactance tester is used to measure leakage reactance and other associated parameters in high voltage power transformers. Leakage reactance, or more generally leakage impedance, is measured at the transformer primary winding while the secondary winding is shorted. Ideally, a transformer’s primary and secondary windings should be 100 % coupled by magnetic flux, but in real transformers there is always a small amount of leakage flux. Leakage inductance is a result of this leakage flux.

With the use of the MLR10’s optional capacitance test probe, electrical measurements can be isolated to individual legs of a complex capacitive bank network. The MLR10 ac voltage source is applied across the appropriate capacitor section (containing the capacitance of interest) and the optional capacitance test probe is used to isolate the measurements specific to the capacitor of interest. The MLR10 is offered as a standalone unit that requires the use of an external PC running Megger’s free MLR10 software.


The MLR10 Software Update will require at least 3 files below.

  • If you know you have Microsoft .Net 4.0 installed on your PC or you are running Windows 10 the will not be required.
  • Depending on the OS version 32bit or 64bit only one of the MLR10v3d6 files will be needed.
  • The will be required.
  •  And the file MLR10_Installation_Guide_1.2.pdf will be required for installation instructions.These instructions are structure to help avoid difficulties after installation. The order of installation and the attachment of equipment to the PC at the right time helps to make a smooth installation.

The Windows 7 MLR10 software will install and run correctly on Windows 7, 8, and 10.

Microsoft .NET 4.0 Full Installation
776.3 KB | 10/12/21
MLR10 v3.6 32bit Software


32 bit version of MLR10 PC Software
203.0 MB | 10/12/21
MLR10 V3.6 64bit software
200.0 MB | 10/12/21
National Instruments Device Drivers for MLR10 DAQ Module
188.2 MB | 10/12/21