NORDAC SK 5xxE Manual
74
Subject to technical alterations
BU 0500 GB
Parameter
Set value / Description / Note
Device
Supervisor
Parameter
set
P108 Disconnection
mode
S P
0 ... 12
[ 1 ]
This parameter determines the manner in which the output frequency is reduced after "Blocking"
(controller enable
Æ
low).
0 = Voltage block:
The output signal is switched off immediately. The FI no longer supplies
an output frequency. In this case, the motor is braked only by mechanical friction.
Immediately switching the FI on again can lead to an error message.
1 = Ramp:
The current output frequency is reduced in proportion to the remaining
deceleration time, from P103/P105.
2 = Ramp with delay:
as with ramp, however for generational operation the brake ramp is
extended, or for static operation the output frequency is increased. Under certain
conditions, this function can prevent overload switch off or reduce brake resistance
power dissipation.
NOTE:
This function must not be programmed if defined deceleration is required,
e.g. with lifting mechanisms.
3 = Immediate DC braking:
The FI switches immediately to the preselected DC current
(P109). This DC current is supplied for the remaining proportion of the >DC brake time<
(P110). Depending on the relationship, actual output frequency to max. quency (P105),
the >DC braking time< is shortened. The time taken for the motor to stop depends on the
application. The time taken to stop depends on the mass inertia of the load and the DC
current set (P109).
With this type of braking, no energy is returned to the FI; heat loss occurs mainly in the
motor rotor.
4 = Constant braking distance:
The brake ramp is delayed in starting if the equipment is
not being driven at the maximum output frequency (P105). This results in an
approximately similar braking distance for different frequencies.
NOTE:
This function cannot be used as a positioning function. This function should
not be combined with ramp smoothing (P106).
5 = Combined braking:
Dependent on the actual link voltage, a high frequency voltage is
switched to the basic frequency (linear characteristic curves only, P211 = 0 and P212 =
0). The deceleration time is retained where possible (P103).
Æ
additional motor warming!
6 = Quadratic ramp:
The brake ramp does not follow a linear path, but rather a decreasing
quadratic one.
7 = Quadratic ramp with delay:
Combination of functions 2 and 6
8 = Quadratic combined braking:
Combination of functions 5 and 6
9 = Constant acceleration power:
Only applies in field weakening range! The drive is
accelerated or braked using constant electrical power. The course of the ramps depends
on the load.
10 = Distance calculator:
Constant distance between current frequency / speed and the set
minimum output frequency (P104).
11 = Constant acceleration power with delay: Combination of functions 2 and 9.
12 = Constant acceleration power with delay (as 11) with additional brake chopper
support
P109
DC brake current
S P
0 ... 250 %
[ 100 ]
Current setting for the functions of DC current braking (P108 = 3) and combined braking (P108 = 5).
The correct setting value depends on the mechanical load and the required deceleration time. A
higher setting brings large loads to a standstill more quickly.
The 100% setting relates to a current value as stored in the >Nominal current< parameter P203.
NOTE:
The amount of DC current (0Hz) which the FI can supply is limited. For this value,
plese refer to the table in Section 8.5.3, column: 0Hz. In the basic setting this limiting
value is about 110%.
