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MTO300 Transformer Ohmmeter - No Controller

Megger MT0300 delivers full eight-terminal/six-winding resistance measurement capability, designed to save time by testing all six windings without having to disconnect & reconnect leads.

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13152.00 incl. VAT)
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Megger MTO300 Transformer Ohmmeter

Save time and money since only one lead set is needed to connect to the transformer!

Measuring a transformer‘s DC resistance from one external terminal to another can reveal a great deal of information about the transformer. In addition to the obvious faulted winding (ie an open winding or shorted turn), more subtle problems can be detected.

The Megger 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.

Its predominant use is the measurement of the DC resistance of all types of transformer windings within the defined range of resistance. It can also test rotating machine windings and perform low resistance measurements on connections, contacts and control circuits. It is recommended that the user becomes familiar with the MTO before making any connection to a transformer.


Megger MTO300 Key Features:

  • Faster testing with one-time connection principle, measures all phases and windings without disconnecting or reconnecting leads
  • “One clamp per designated bushing” concept significantly reduces chance of operator error in making lead set connections
  • Automated eight-terminal/six-winding measurement capability saves time and eliminates the need for external jumper cables
  • Simultaneous winding magnetisation (SWM) method giving fast, reliable measurements even on large transformers with delta configuration on the low voltage side
  • Interchangeable lead set with the Megger TTR300 series of 3-phase turns ratio instruments saves time and money
  • DC test current up to 10 A
  • Built-in discharge circuit safely discharges the specimen when test is completed, if lead accidentally disconnects, or if power is lost
  • Built-in demagnetisation circuitry allows the operator to de-magnetise the transformer core upon completion of resistance testing, or as a stand-alone feature before SFRA testing or when the transformer is put back in service
  • Custom PowerDB form for production heat-run (interval) testing
  • PowerDB software allows for data analysis and trending while in the field without the use of an external computer
  • The user can easily recall transformer set ups from a custom-settings menu with PowerDB
  • PC interface via USB for remote control operation and downloading of test results for ease of use


Megger MTO300 Applications:

  • Verify factory test readings
  • Help locate the presence of defects in transformers such as increased contact resistance in terminal connections and tap-changers
  • Check the operation of on-load tap changers


Comparison Chart for: Megger MTO300 Transformer Ohmmeter - No Controller

Maximum windings connected22266
Max DC test current in A610501010
Direct digital read out
PC Control
PC on-board


Accessory Code Description Price (Ex VAT)
2005-340 Transit Case MTO £875.00 ADD
30915-220 Hand-Held TEST siwtch assembly for remote operation £315.00 ADD
36486-8 CABLE ASSY - H EXTENSION 33 FT £840.00 ADD
36486-9 3Ø SHIELDED TEST LEAD SET EXT. - X AND H £1,660.00 ADD