SKF AWAIV-12, Руководство пользователя

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Synchronous motor/generator
Test the synchronous stator as a three-phase induction motor. You should test the rotating
fields individually.
1) Before surge testing the stator, remove the DC leads to the brush boxes or lift all of
the brushes off of the slip rings.
2) Short the slip rings for the rotating fields together.
3) Perform a surge test on the stator following the procedure for three-phase motors.
4) Individual poles are surge tested as outlined in the procedures for testing single-
phase motors and two-terminal devices. An example test voltage is 600 V per pole,
but for your purposes you should check with the manufacturer for the proper test
voltage or carefully evaluate the insulation system’s dielectric strength and choose an
appropriate test voltage. It is not necessary to disconnect the pole piece leads before
testing.
If the wave patterns are stable and they superimpose on the display, the windings are
identical; they have no faults and the insulation of both coils is good.
NOTE
You can test one field and store its surge wave pattern for reference. You can then
compare the other fields to this reference pattern in a procedure similar to that of
two or more single coils.
Determining faults
Two types of faults may exist in synchronous motors and generators: pole piece faults or
stator winding faults.
Pole piece fault
Do not expect coils to compare exactly. Rotating fields or pole pieces are often not wound to
identical, exacting standards. If a fault does exist in the pole pieces of the test, the wave
pattern on the display will collapse in amplitude and a distinct shift to the left will occur,
signifying an increase in frequency (a decrease in inductance). This type of fault is usually
failure of the turn-to-turn insulation.
NOTE
The turn insulation on pole windings can by very thin. Take care not to overstress
the insulation with too high of a test voltage. Also, the windings might compress as
the rotor spins during operation, which can short adjacent turns. Unfortunately,
simulating centrifugal forces is not possible when surge testing.
Stator winding fault
For a stator winding fault, if the wave pattern changes and becomes erratic during the test,
then intermittent shorting or arcing is occurring in the winding under test. Separation of
waveforms indicates either hard shorts or unequal rotor coupling for the difference stator
phase windings.
SKF Static Motor Analyzer—Baker AWA-IV User Manual 135
Motor testing theory and reference