Fairford Electronics QFE Series, Manual

Page: 131 / 194

Programming
page 5-20
QFE
FD8420 issue02_F
Figure 5.3.5d Overload Trip Graph
Notes
1.
Delay = ‘Overload Delay’.
Overload Level
- This parameter holds the level in Amps at which an
Overload
trip will start integrating (see the graph below). The default value for this parameter
is 1.1
×
Unit Full Load Current, but is expressed in Amps. Special case: if a load current
exceeding 7.2 x FLC occurs for longer than 60 mS, a
Shearpin Trip
is forced whenever
the
Overload
is
On
, see section 5.3.11 .
Overload Delay
- This parameter holds an arbitrary dimensionless number
which slows down the integration of an
Overload
trip. The larger the value of the number
stored here, the longer a given
Overload
will take to result in a trip. The default value of
this parameter is 140.
0.01
0.1
1
10
100
1000
1
2 3 4 5 6 7 8 9 10
Fault current ( Motor Current x N )
Seconds
to trip
Overload start point
Delay = 80
Delay = 30
Delay = 10
(Default) Delay = 140
7.2 x FLC Shearpin Cutoff