Description
The Model 258 continuously
monitors 3-phase power lines
for abnormal conditions. When
properly adjusted, the Model
258 monitor will detect phase
loss on a loaded motor even
when regenerated voltage is
present. This device consists
of a solid-state voltage and
phase-angle sensing circuit,
driving an electromechanical
relay. When correct voltage
and phase rotation are
applied, the internal relay
will energize. A fault
condition will de-energize
the relay. When the fault is
corrected, the monitor will
automatically reset (a manual
reset version is also
available). The Model 258
does not require a neutral
connection and can be used
with Wye or Delta systems.
Voltage ranges are
sufficiently wide to allow
for proper adjustment to
existing conditions. Both
TRIP and NORM condition
indicators are provided to
aid in adjustment and system
trouble-shooting.