Fluke 434 - Manual (Page 41)

Dips & Swells
Tips and Hints
9
9-5
The following Abbreviations and Symbols are used in the tables:
Abbreviation Description Symbol Description
CHG Rapid Voltage Change Rising voltage edge
DIP Voltage Dip Falling voltage edge
INT Voltage Interruption
SWL Voltage Swell
Available function keys:
F3 Switch between NORMAL and DETAILED event table.
F4 Return to Trend screen.
F5 Access Trend screen with Cursor on and positioned on the
highlighted event.
This event can be selected with the up/down arrow keys
Tips and Hints
The occurrence of Dips (Sags) and Swells may indicate a weak power distribution
system. In such a system voltage will change considerably when a big motor or a welding
machine is switched on or off. This may cause lights to flicker or even show visible
dimming. It may cause reset and loss of data in computer systems and process controllers.
By monitoring the voltage and current trend at the power service entrance, you can find
out if the cause of the voltage dip is inside or outside the building. The cause is inside the
building (downstream) when voltage drops while current rises; it is outside (upstream)
when both voltage and current drop.