Transformer ohmmeter

  • Direct two-channel digital reading (1 µΩ to 2000 Ω)
  • DC test current up to 10 A maximum
  • 0.25 % measurement accuracy
  • Integrated demagnetization feature
  • Tests operation of on-load tap changers
  • Very fast auto safety discharge circuit

The MTO210 transformer ohmmeter is a line-operated, field-portable instrument designed specifically to measure the DC resistance of all types of magnetic windings safely and accurately. It can test transformers and rotating machine windings and perform low-current resistance measurements on connections, contacts and control circuits.

The dual set of potential inputs measures the resistance of the primary and secondary windings of a single- or three-phase transformer simultaneously. This dual reading, dual injection characteristic, also helps to speed up the measurements when used to test low voltage windings on large three-phase power transformers.

The MTO210 is extremely useful when testing the windings and contact resistance of tap changers with 'make-before-break' contacts and voltage regulators. This action will check for pitted or misaligned contacts as the instrument will give an indication if either condition occurs. You are also protected by the auto-shutdown safety feature and any inadvertent disconnection of a test lead or loss of power to the instrument will safely discharge the energy stored in the unit under test (UUT).

Technical Documents
Technical guide
Guide to transformer winding resistance measurements
Technical guide
Transformer Tap Changer Testing