Baker Instrument Company PP24 User Manual page 35

Surge Testing AWA Unit
Fig 5-2: AWA surge screen
By moving the red test lead from on phase then to the next phase as described above, the
motor is completely tested.
The indication of an arcing turn-turn insulation failure is a jump to the left of the surge
waveform as the voltage is increased. The shift may also be accompanied by a slight drop in
the amplitude of the waveform. If the ppEAR (Pulse to Pulse EAR) feature of the AWA is
turned on, the AWA will most likely identify the arcing fault and may shut the test down. If the
ppEAR feature is turned off, the operator will have to closely monitor the waveform looking
for the jump to the left of the waveform that is the indication of the arcing fault.
T
he indication of a welded turn-turn short is a waveform that never jumps to the left but stays
shifted to the left of the other two waveforms. Usually, if one of the three waveforms is
shifted due to a welded fault, all three will be separated when compared to each other. If the
L-L EAR (Line to Line EAR) feature is turned on, the AWA software can fail the motor based
on the separation of the waveforms.
The details of performing a surge test will now be described (this discussion assumes both the
AWA and PP24 are connected and powered up as described at the beginning of this chapter):
Fig 5-3: Function knob PP24
1) Turn the Function knob on the PP24 to the surge position.
12/7/2009 | 71-026 V2
PP24
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