15
finished or until the measured resistance limit is higher than the
programmed limit.
3.4. Voltmeter
By pressing the key, the equipment will measure the voltage effectively
applied to the element being tested.
3.5. Memory (HOLD)
The key allows to hold the last performed reading on the display, at the
moment this key was pressed, without interrupting the test. When this key
is pressed again, the equipment updates the resistance and time values.
The key led and the letter
H
on the display indicates that the function
was activated.
3.6. Filter
When insulation measures are carried out in transformers or in large
dimension machines, in presence of strong electromagnetic fields, it is
possible that the equipment reading is unstable, especially for resistance
values higher than 300 M
Ω. In these cases it is convenient to press the
key before starting the measurement. This function allows to reach the
insulation resistance value in an upward curve without significant
oscillations.
3.7. Dielectric Absorption Index (DAI)
The key makes it possible to visualize the Dielectric Absorption Index
value on the display. For this kind of test, the equipment should be
connected, applying voltage to the sample for 60 seconds. After this
period, the operator must press the key to read the absorption index
value on the display. If this key is pressed before the 1-minute period has
elapsed, the display will show DAI = - - -. The Dielectric Absorption Index
is the ratio between the insulation resistance value measured after 60
seconds and the value measured after 30 seconds. This value is useful to
determine whether it is necessary to perform preventive and predictive
Summary of Contents for MD-5060 Series
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