Open Event; Impulses; Impulse Events - ACR Electronics PowerWatch Reference Manual

5.2.1.1

Open Event

Open Event
An event which has not yet terminated.
5.2.1.2

Impulses

Impulses
Impulses are transient voltage fluctuations (sometimes called spikes). They
can be positive or negative and can occur on the hot-neutral line or on the
neutral-ground line. Impulses typically have a duration far below one cycle
time and can be detected below microsecond.
PowerWatch will record any voltage deviation above the impulse limit and of
less than one cycle duration as an impulse event.
5.2.1.3

Impulse events

Impulse Events
Impulses are transient voltage fluctuations (sometimes called spikes), can be
positive or negative, and can occur on both the hot-neutral line and the
neutral-ground line. The voltage potential of an impulse can be quite large;
hundreds of volts is not uncommon. Impulses typically have a duration far
below one cycle time and can be detected below a microsecond. PowerWatch
will record any voltage deviation above the impulse threshold of less than one
cycle duration as an impulse.
PowerWatch can detect both positive and negative
microsecond in duration on both the H-N and N-G lines. If the voltage exceeds
the impulse deviation threshold within one half cycle, an impulse event will be
recorded. An impulse event can include one or more impulses occurring within
the same half cycle. The event column will display the number of impulses
that the PowerWatch was able to count.
An important point to note about a multiple impulse event is that the voltage
reading in the Extreme column will be the total voltage of any impulses that
occur more than 100 microseconds apart. When multiple impulses of different
polarity occur, their absolute values are added together. The degree (in the
fourth column) will be the position in the cycle of the first impulse. The angle of
neutral-ground impulses is referenced to the start of the hot-neutral sine wave.
If an impulse is less than one microsecond in length, PowerWatch will
measure the magnitude of the impulse but may be unable to determine the
polarity. In this case, PowerWatch will show the sign of the impulse as "+"
(firmware version 4 or greater).
2007 ACR Systems Inc.
PowerWatch Operating Overview
impulses
50
down to one