The Artificial Neutral Model AN-1 generates a momentary grounded
artificial neutral to allow the measurement of fault currents on
ungrounded three-phase systems.
The Artificial Neutral is grounded intermittently through a relay driven
by an internal electronic timer. This periodic grounding technique
performs three functions – limits the possibility of insulation faults
within the instrument, allows for better discrimination of actual fault
current and limits instrument overheating.
Relay closure time is switch selectable, Fast (0.5 seconds) or Slow (2.3
seconds), so that the ground fault clamp can be used on a meter with
either an analog or digital display. An internal buzzer, also driven by
the relay, is activated each time the neutral connection is grounded.
Three LEDs, one for each phase, show the presence of each of the three
phases prior to measurement. A fourth green LED indicates that the
instrument is operating. |
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