AVTMMTO210 Rev 7 Sept 2013
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Getting to know the MTO210
Product Overview
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 ranges of current and resistance. It can
also test rotating machine windings and perform low-current resistance
measurements on connections, contacts and control circuits.
Four features are combined to make this instrument unique: dual measurement
and current injection, on-load tap-changer testing, automatic discharge and
demagnetization..
The dual set of potential inputs, simultaneously measure the resistance of the
primary and secondary windings of a single- or three-phase transformer. The
dual reading characteristic will speed up the measurement when current leads are
driving more than one winding.
The Transformer Ohmmeter is extremely useful when testing the windings and
contact resistance on tap-changers with make-before-break contacts and voltage
regulators. A warning light will flash and the internal shutdown circuit will be
triggered if the tap-changer contacts have a break before make event. This action
checks for pitted or misaligned contacts and indicates such events.
Likewise users are protected by the shutdown circuit safety feature: any
inadvertent disconnection of a test lead or loss of power to the instrument will
safely and quickly discharge the energy stored within the test sample.
The MTO210 has an added post test feature. At the end of a transformer test,
the instrument has a demagnetization function. This function will cycle thru the
transformer with alternating DC current. At the end of 8 cycles, the transformer
core is demagnetized.
The Transformer Ohmmeter's wide resistance range (1 micro-ohm to 1999
ohms) gives a high degree of resolution for even the lowest winding resistance
tested.
Summary of Contents for MTO210
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