Sourcetronic MD-5060 Series, Руководство пользователя

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maintenance on the coils (transformers, engines and motors, generators,
etc.).
3.8. Polarization index (PI)
The key makes it possible to visualize the Polarization Index value on
the display. For this type of test, the equipment must be connected and
applying voltage to the sample for 10 minutes. After this period, the
operator must press the
key to show the PI value on the instrument
display. If the key is pressed before the 10-min period has elapsed, the
display will show PI= - - -. The polarization index is the ratio between the
insulation resistance value measured after 10 min and the value
measured after 1 min. This index is useful to determine whether it is
necessary to perform preventive and predictive Maintenance in order to
detect any insulation resistance wear and tear due to the excess of dust,
dirt, grease, or else the action of chemical or physical agents, etc.
3.9. Step Voltage Test (SVT)
After selecting the SVT function with the key, the operator must select
the test maximum voltage with the key. In this function, the equipment
allows the selection of maximum voltages only from 500 V up to 5000 V in
500 V steps. If the operator selects a halfway voltage between two 500 V
steps by using the key, the equipment will carry out the test from the
500 V up to reaching an equal voltage value or a value that is straight
below the 500 multiple value. During the first minute the generated test
voltage is of 500 V. This voltage is incremented in 500 V steps until it
reaches the maximum programmed voltage. Each voltage step is applied
during one minute, and the resistance is measured before going up to the
following voltage. The test result is calculated with this formula: