Ramps & brakes setup (Control panel: Menu PAR
The start and end of the acceleration and deceleration ramp can be
smoothed with this parameter. Setting value 0 gives a linear ramp shape
which causes acceleration and deceleration to act immediately to the
changes in the reference signal.
Setting value 0.1...10 seconds for this parameter produces an S-shaped ac-
celeration/deceleration. The acceleration and deceleration times are deter-
mined with parameters 4.2 and 4.3.
Fig. 52. S-shaped acceleration/deceleration
Application manual HVAC232/402 | Document 27-652 | Issue ENG06 | 2019-08-07
Acceleration time 1
Deceleration time 1
Ramp S-shape 2
Acceleration time 2
Deceleration time 2
These limits correspond to the time required for the output frequency to
accelerate from the zero frequency to the set maximum frequency, or to
decelerate from the set maximum frequency to zero frequency.
The user can set two different acceleration/deceleration time and set two
different ramp s-shape for one application. The active set can be selected
with the selected digital input (par. 5.11).
Instead of DC braking, flux braking is a useful form of braking with motors
of max. 15 kW.
When braking is needed, the frequency is reduced and the flux in the motor
is increased, which in turn increases the motor's capability to brake.
Unlike DC braking, the motor speed remains controlled during braking.
Flux braking converts the energy into heat at the motor, and
should be used intermittently to avoid motor damage.