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PA-9 Series
Application Guide
EQUIPMENT TRIPPING OUT
Equipment Tripping Out problems are most associated with
sags and swells. In many industries with critical process loads, even
instantaneous short duration phenomena can cause process
shutdowns requiring hours to re-start. In these facilities, the effect
on the process is the same for a short duration variation as for
long duration phenomena. Transient voltages caused by lightning
or switching operations can result in degradation or immediate
dielectric failure in all classes of equipment.
Common Causes of voltage sags include source voltage changes,
inrush currents as well as inadequate wiring.
Common Causes of voltage swells can include load switching or
utility faults.
Common Causes of transients include lightning, load switching,
capacitor switching as well as loose wiring.
Another Common Cause includes the wrong voltage for
equipment in use coming into the building. These wrong voltages
can include 230volt equipment being fed from 208 volts or vice
versa, 460 volt equipment being fed from 480 volts.
Note: Some 460 volt equipment have over-voltage, under-voltage
and phase lost relays, when 460 volt equipment gets to 10% or
about 506volts it causes an over-voltage trip or alarm. A Utility
voltage can be at the upper limit of 504 volts and when a utility cap
comes on the voltage may go to 508 for less than a cycle and
causing an over-voltage trip.
Note: Open Delta and Closed Delta transformer banks are very
inefficient with no load, so is they are under-sized they become
even more of a problem.
Example of a Sag
Sag
Time
12/22/2004 - 13:00:00 12/22/2004 - 13:19:00 12/22/2004 - 13:38:00 12/22/2004 - 13:57:00 12/22/2004 - 14:16:00
47.00
72.28
97.56
122.84
148.12
Va MIN (Volts)
PA-9 Configuration
Feature Status Notes
Enable Power Calculations Enable (Select correct configuration)
Enable RMS Recording Enable
MIN, RMS and MAX MIN, RMS and MAX
Clock Hour Orientation Enabled
Enable Flicker Recording Disabled
Hysteresis 2%
Sags Enabled
Sag Limit See Below
Swells Enabled
This configuration is designed to
capture out of limit events. It
focuses on sub-cycle, sag and swell
events.
In this configuration the waveform
capture is set to Exceedance. This
will allow the unit to capture a
waveform every time there is an
out of limit event. By analyzing the
waveforms associated with
transients one can determine