Nord Drivesystems SK 180E Series, User Manual

Page: 98 / 212

NORDAC BASE (SK 180E / SK 190E) – Users Manual for Frequency Inverters
98 BU 0180 en-4118
P108
Disconnection mode
(Disconnection mode)
S P
0 ... 13
{ 1 }
This parameter determines the manner in which the output frequency is reduced after "Blocking"
(controller enable

Low).
0 = Block voltage : The output signal is switched off immediately. The FI no longer supplies an
output frequency. The motor is only braked by mechanical friction. Switching the FI on again
immediately can lead to an error message.
1 = Ramp : The current output frequency is reduced in proportion to the remaining deceleration
time, from P103/P105. The DC run- on follows the end of the ramp (→ P559).
2 = Ramp with delay: as for 1 "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. frequency (P105), the >Time
DC brake on< 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.
Not for PMSM motors!
4 = Const. brake distance, "Constant brake 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, "Combined braking" : Dependent on the actual link voltage (UZW), a high
frequency voltage is switched to the basic frequency (only for linear characteristic curves,
P211 = 0 and P212 = 0). The braking time (P103) is complied with if possible.

Additional
heating in the motor!
Not for PMSM motors!
6 = Quadratic ramp
: The brake ramp does not follow a linear path, but rather a decreasing
quadratic one.
7 = Quad. ramp with delay , "Quadratic ramp with delay" : Combination of functions 2 and 6
8 = Quad. comb. braking, "Quadratic combined braking" : Combination of functions 5 and 6
Not for PMSM motors!
9 = Const. acceln. power, "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 actual frequency / speed and the set
minimum output frequency (P104).
11 = Const. acceln. power with delay , "Constant acceleration power with delay" : Combination of
functions 2 and 9.
12 = Const. acceln. power mode 3, "Constant acceleration power mode 3" as for 11, however
with additional relief of the brake chopper
13 = Disconnection delay, „"Ramp with disconnection delay“ : as for 1 "Ramp" , however, before
the brake is applied, the drive unit remains at the absolute minimum frequency set in
parameter (P505) for the time specified in parameter (P110)
.
Application example: Re-positioning for crane control