Application Guide - NP900 Series
431 (504
)
A996A
Table 3.6.5.4-253 Operating time characteristics setting parameters.
Name
Range
Step
Default Description
Tset
0.000…1800.000s 0.005s 10.000s CLPU start timer, this setting defines how long the ILow
condition has to last before CLPU is activated.
Tmax
0.000…1800.000s 0.005s 30.000s CLPU max timer, this setting defines how long the
starting condition can last and the current is allowed to
be over IHigh.
Tmin
0.000…1800.000s 0.005s 0.040s
CLPU min timer, this setting defines how long the
starting condition last for minimum time. In case if the
start up sequence includes more than one inrush
situation this parameter may be used to prolong the
CLPU time over the first inrush. Also this parameter
operates as “reclaim” time for the CLPU function in case
the inrush current is not immediately initiated in the start-
up sequence.
In following figures are presented few typical cases of CLPU situations.
Figure 3.6.5.4-200 Example of timers and pick-up parameters. Normal CLPU situation.
CLPU activates after current has been under
ILow
setting for time
Tset .
When current
exceed the IHigh setting the maximum allowed CLPU timer start to count until
Tmax
time.
In this example the pick-up current is cleared before the
Tmax
time. When the measured
current is in between of
ILow
and
IHigh
the start-up condition is considered to be over.
The CLPU signal can be prolonged over this time by setting
Tmin
to higher value than
0.000s.