Preparing Equipment Under Test
Isolation is a key factor in properly testing any insulation
resistance value. Whether you are testing a motor winding,
transformer winding or a cable, you must ensure that the
component you are evaluating has no path to ground or other
circuits. Contactors and switches must be open and terminal
connections must be removed prior to testing.
Your insulation resistance tester is designed to place the DC
charge on the “
LINE
” terminal while the “
EARTH
” terminal
often shares the grounded contact with all other components.
You can only test one cable, winding or component at a time,
but they ALL need to be tested independently (Fig 4).
(Fig 4)
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