Inrush Currents - PeakTech 4145 Bedienungsanleitung

 Tips and Hints
Disturbances such as transients in a power distribution system can cause
malfunctions in many types of equipments. For example, computers may reset and
equipment subjected to repeated transients can eventually fail. Events occur
intermittently, making it necessary to monitor the system for a period of time to find
them. Look for voltage transients when electronic power supplies are failing
repeatedly or if computers reset spontaneously.

7.10. Inrush currents

Inrush currents can be captured by the Analyzer. Inrush currents are surge currents
that occur when a large, or low-impedance load comes on line. Normally the current
will stabilize after some time when the load has reached normal working condition.
For example the start-up current in induction motors can be ten times the normal
working current. Inrush is a 'single shot' mode that records current and voltage
Trends after a current event has occurred. An Inrush occurs when the current
waveform exceeds adjustable limits. The Trends builds up from the right of the
screen. Pretrigger information allows you to see what occurred in advance of the
inrush.
 Trend display
Use the arrow keys in the Start menu to adjust the trigger limits: expected inrush
time, nominal current, threshold and hysteresis. The maximum current determines
the vertical height of the current display windows. Threshold is the current level that
triggers the trend capture. The inrush time is the time between trigger and the time
that the current falls to the value indicated by Hysteresis and is indicated on the trend
display between two vertical markers. The screen header displays the rms of all
phases during the inrush time. If the Cursor is on, the rms measuring values at the
Cursor are displayed.
Available function keys:
F1 Switch parameters to be displayed.
F3 Access to Cursor.
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