38
DC Braking
Applying DC current to the motor will brake the motor. Parameter 114,
DC Braking Current, sets the DC braking current as a percentage of
the rated motor current. Parameter 115, DC Braking Time, sets the
amount of time that the DC current will be applied. Parameter 116, DC
Brake Cut-in Frequency, sets the frequency at which DC braking
begins when the motor decelerates during a stop.
If terminal 19 or 27 (parameters 303 or 304 Digital Input) has been
programmed to DC Braking Inverse and shifts from logic ‘1’ to logic ‘0’,
the DC braking will be activated immediately.
When the start signal on terminal 18 changes from logic ‘1’ to logic ‘0’,
the DC braking will be activated when the output frequency becomes
lower than the brake cut-in frequency.
If a DC brake current is set in parameter 114, the drive’s switching
frequency will be limited to 4 kHz during the braking.
WARNING
!
A high braking current supplied for a long time
will overheat motor. Use only the DC braking
current and time required.
CAUTION
!
Do not use DC braking function if inertia of
driven load is more than 20 times inertia of
motor.
114
DC Braking Current
(DC BRAKE CURRENT)
Value:
0 to 100%
★
50 %
The maximum value depends on the rated motor current.
Function:
This parameter is used for setting the DC braking current that is
applied:
1.
When the DC brake frequency set in parameter 116 DC Brake
Cut-in Frequency has been reached during a stop.
2.
When DC brake inverse is active via terminal 19 or 27, or via the
serial bus.
The DC braking current will be active for the duration of the DC
braking time set in parameter 115 DC Braking Time.
Description of choice:
To be set as a percentage value of the rated motor current set in
parameter 105 Motor Current.
100% DC braking current corresponds to the value set in parameter
105.
115
DC Braking Time
(DC BRAKE TIME)
Value:
0.0 to 60.0 sec.
✭
10.0 sec.
Function:
This parameter sets the time that the DC braking is active.
Description of choice:
Set the desired time.
116
DC Brake Cut-in Frequency
(DC BRAKE CUT-IN)
Value:
0.0 (OFF) to setting of parameter 202
✭
OFF
Function:
This parameter is used for setting the frequency at which DC braking
begins after a stop command is issued.
Description of choice:
Set the desired frequency for braking to begin upon deceleration.
CAUTION
!
Most HVAC applications do not required brak-
ing or holding. It is suggested that parameter
114 remains set at 0 unless unusual applica-
tion requirements call for braking or holding
torque.
✭
Indicates default parameter. Depending upon the application, the drive may be delivered with other parameters selected.
