AEMC 8335 User Manual page 81

• Harmonic Number:
which harmonic number is being used as an alarm condition. For example,
Vh with a harmonic number of 2, will only look at Voltage phase to neutral,
harmonic 2.
• Phases: Some alarm conditions have a phase selection. W, VAR, and VA,
have a choice of "3L" (each individual phase), or "Sum" which is the sum of
phases. DPF, PF, and TAN have the choice of "3L" (each individual phase), or
"Mean" which is the mean of phases.
• Threshold:
the value or higher must be reached, for "<" alarms, the value or lower must
be reached.
• Duration:
The Alarm will only be recorded if the duration of the param-
eter meeting the threshold criteria exceeds the duration. The minimum
alarm duration can be in minutes or seconds. In the case of Vrms, Urms
or Arms not using neutral current, can also be in hundredths of a second.
For Vrms, Urms, and Arms, it can be useful to set a duration of 0 seconds. In
that case an event as short as a half cycle can be detected (8 milliseconds at
60Hz). For all other parameters, the minimum duration that can be detected
is 1 second.
• Hysteresis:
event that goes above the threshold and a certain percentage below it at
times.
Example: Alarm threshold is 100 Volts or higher, hysteresis is 1%. When the volt-
age goes up to 100V, the alarm condition starts. When it goes back down to 99V,
the alarm condition stops.
NOTE: You can configure alarms, recordings, inrush, and transient searches while
testing is in progress.
Power Quality Analyzer Model 8335
For alarm parameters, Vh, Ah, Uh, and VAh, selects
The value that must be reached to start an alarm. For ">" alarms,
This value for alarms is set to prevent multiple recordings of an
79