NORD Drivesystems BU0750 User Manual
Page 85
BU 0750 GB-3311
Subject to technical amendments
85
Parameter
Setting value / Description / Note
Parameter
set
Available in Option
P108
Disconnection mode
P
Always visible
0 ... 12
[ 1 ]
This parameter determines the manner in which the output frequency is reduced after "Blocking"
(controller enable 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. Immediate
switching on again of the FI can lead to error switch off.
1 = Ramp: The actual output frequency is reduced proportionally to the remaining braking time
from P103.
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. frequency (P105), the >Time
DC brake on< is shortened. The time taken for the motor to stop depends on the application.
The deceleration time depends of the moment of inertial of the load and the DC current which
is set (P109).
With this type of braking, no energy is fed back to the FI. Heat losses occur, mainly in the
rotor of the motor.
4 = Constant brake distance: The brake ramp is delayed in starting if the equipment is not being
driven at the maximum output frequency (P105). This leads to an almost constant braking
distance from various frequencies.
Note:
This function cannot be used as a positioning function. This function should
not be used with ramp rounding (P106).
5 = Combined braking: Depending on the actual link voltage (CLV) a high frequency voltage is
applied to the basic mode (linear characteristic curves only, P211 = 0 and P212 = 0). The
braking time is retained where possible (P103). additional motor warming!
6 = Quadratic ramp: The braking ramp does not have a linear course, but rather is quadratic.
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 the field weakening range! The drive is
accelerated and 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 = Constant acceleration power with delay: Combination of functions 2 and 9.
12 = Constant acceleration power with delay (as for 11) with additional chopper relief
P109
DC brake current
P
Always visible
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.
P110
DC braking time on
P
Always visible
0.00 ... 60.00 s
[ 2.00 ]
The time during which the motor has the current selected in parameter >DC brake current< applied
to it during the DC braking functions (P108 = 3).
Depending on the relationship, actual output frequency to max. frequency (P105), the >Time DC
brake on< is shortened.
The time starts running with the removal of the enable and can be interrupted by fresh enabling.