50 ELECTRIC DISCHARGES, WAVES AND IMPULSES.
rent wave, therefore, is symmetrical, and the field current shows
only the double-frequency pulsation. Only a few half-waves were
recorded before* the circuit breaker opened the short circuit.
only the double-frequency pulsation. Only a few half-waves were
recorded before* the circuit breaker opened the short circuit.
Fig. 27. — CD5128. — Symmetrical. Momentary Single-phase Bhort Circuit
of Alternator, Oaoillogram of Armature Current, Armature Voltage,
and Field Current. (Circuit breaker opens,)
of Alternator, Oaoillogram of Armature Current, Armature Voltage,
and Field Current. (Circuit breaker opens,)
Fig. 28. — CD6565. — Asymmetrical Momentary Single-phimi Bhort Circuit
of SQQQ-Kw. 11,000-Volt Three-phase Alternator
Osoiliogram of Armature Current and Field Current*
of SQQQ-Kw. 11,000-Volt Three-phase Alternator
Osoiliogram of Armature Current and Field Current*
Fig. 28 shows the single-phaise short circuit of a 6-polar 5000-kw.
11,000-volt ateam turbine alternator, which occurred at a point of
the wave where the armature current should bo not far from its
maximum. The transient armature current, therefore, starts ua-
the wave where the armature current should bo not far from its
maximum. The transient armature current, therefore, starts ua-