PMI Eagle 220, Руководство пользователя

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What the Eagle™ Records
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specifies how close the sum of the two voltages must be to twice
the nominal voltage. For example, a range of 12V means that the
sum of the two legs must be within 12V of twice the nominal
voltage. Both the range and the difference conditions must be
met for at least the number of seconds specified by the duration.
If the duration is set to five seconds, then the difference and range
conditions must be met for five consecutive seconds before a
loose neutral is declared. One-second average voltages are
used. The nominal voltage is the nominal determined during the
two-minute countdown by the abnormal voltage record type, and
is typically 120V in a single-phase hookup. As an example,
assume the difference parameter is 16V, and the range 12V, with
5-second duration. The two line voltages are 119 and 121V.
Then one leg moves to 128V, and the other to 110V. The
difference between the two legs is 18V, which meets the
difference threshold. The sum of the two voltages is 238V, which
is within the required 12V (specified by the range value) of twice
the nominal (240V). If these voltages persist for 5 seconds in a
row, then a loose neutral record will be triggered.
If one voltage leg changes due to heavy loading, the range
parameter keeps the loose neutral from false triggering. For
example, if the voltages start at 119V and 121V, then a heavy
load to channel 1 causes it to drop to 105V, with the other leg still
at 121V, the difference condition is met (121 × 105 > 12), but the
range condition is not met: 105 + 121 = 226, and 226V is not
within 12V of the 240V nominal.
What is Recorded
The date and time of the loose neutral triggering is recorded,
along with the voltage on the two channels. Only the first
occurrence of a loose neutral is recorded; if the conditions are met
again, nothing further happens. The loose neutral report shows
whether the neutral may have a bad connection, not the exact
times the connection was made and broken.
Typical Settings and Suggested Uses
The loose neutral report can show the symptoms of an actual
loose neutral connection. It is worth investigating if the report is
triggered. However, it is possible for the loose neutral logic to be
fooled. If both legs are equally loaded, then the two voltages will