
The short circuit behaviour depends on the 3 current
transducers in the motor phases and the desaturation
protection with feedback from the brake.
R+
82
R-
81
Brake
Resistor
U 96
V 97
W 98
Inrush
R inr
P 14-50
L1 91
L2 92
L3 93
M
130BC965.10
Illustration 2.3 Control Principle
2.1.2 Internal Current Control in VVC
plus
Mode
The frequency converter features an integral current limit
control which is activated when the motor current, and
thus the torque, is higher than the torque limits set in
4-16 Torque Limit Motor Mode
,
4-17 Torque Limit Generator
Mode
and
4-18 Current Limit
.
When the frequency converter is at the current limit during
motor operation or regenerative operation, it reduces
torque to below the preset torque limits as quickly as
possible, without losing control of the motor.
Smart Logic Control (SLC) is essentially a sequence of user-
defined actions (see
13-52 SL Controller Action
[x]) executed
by the SLC when the associated user-defined
event
(see
13-51 SL Controller Event
[x]) is evaluated as TRUE by the
SLC.
The condition for an event can be a particular status or
that the output from a Logic Rule or a Comparator
Operand becomes TRUE. That leads to an associated
Action as illustrated in
.
. . .
. . .
Par. 13-43
Comparator Operator
Par. 13-43
Logic Rule Operator 2
Par. 13-51
SL Controller Event
Par. 13-51
SL Controller Action
130BB671.10
Coast
Start timer
Set Do X low
Select set-up 2
. . .
Running
Warning
Torque limit
Digital inpute X 30/2
. . .
=
TRUE longer than..
. . .
. . .
Illustration 2.4 Current Control Status/Event and Action
Events and
actions
are each numbered and linked together
in pairs (states). This means that when
[0] event
is fulfilled
(attains the value TRUE),
[0] action
is executed. After this,
the conditions of
[1] event
will be evaluated and if
evaluated TRUE,
[1] action
will be executed and so on. Only
one
event
will be evaluated at any time. If an
event
is
evaluated as FALSE, nothing happens (in the SLC) during
the current scan interval and no other
events
will be
evaluated. This means that when the SLC starts, it
evaluates
event
[0] (and only
[0] event
) each scan interval.
Only when
[0] event
is evaluated TRUE, will the SLC
Product Overview
VLT
®
Decentral Drive FCD 302
12
MG04H102 - VLT
®
is a registered Danfoss trademark
2
2