Baker D30R, User'S Manual & Operating Instructions

Page: 86 / 142

D30R Users Manual
86
Do Not Touch Test Leads while test is in Progress!
71-023 Rev C 5/8/2007
Fig 8-3: Good Coil & Bad Coil
If any wave pattern becomes erratic and/or flickers during testing, intermittent
shorting or arcing is probably occurring in the windings under the voltage stress.
Arcing is often accompanied by audible sounds. It may be desirable to store the
wave pattern produced by this arcing for reference if the operator can release the
TEST (this freezes the wave pattern.) at the moment when the wave pattern
appears the most affected by the fault (reduced amplitude and increased
frequency or shift to the left).
Form Coils
Form coils should be tested similarly to a two terminal device (see Single Phase
Motors and Two Terminal Devices). The Surge test is recommended for form
coil testing because it alone can generate the turn-to-turn voltage that is required
in these low impedance coils.
Determination of a Fault
Refer to the previous section on Single Phase and Two Terminal Devices to
determine if a fault is present.
Notes and Tips for Form Coils
•
IEEE-522-1992 recommends a test voltage for Vacuum Pressure
Impregnation coils, before they are cured, of 60-80 percent of the test
voltage of fully cured coils.