Specifications

Softstart UK Operation
• Brake
Brake reduces the time the motor requires to stop.
During braking an increased noise level from the motor may be audible. This is a normal part of motor braking.
When brake is selected, the LV-DS uses DC injection to slow the motor.
LV-DS braking:
• Does not require the use of a DC brake contactor
• Controls all three phases so that the braking currents and associated heating are evenly distributed through
the motor.
CAUTION
If the brake torque is set too high, the motor will stop before the end of the brake time and the motor
will suffer unnecessary heating which could result in damage. Careful configuration is required to
ensure safe operation of the starter and motor.
A high brake torque setting can result in peak currents up to motor DOL being drawn while the motor
is stopping. Ensure protection fuses installed in the motor branch circuit are selected appropriately.
CAUTION
Brake operation causes the motor to heat faster than the rate calculated by the motor thermal model.
If you are using brake, install a motor thermistor or allow sufficient restart delay (parameter 5A).
Braking has two stages:
• Pre-brake: provides an intermediate level of braking to slow motor speed to a point where full brake can be
operated successfully (approximately 70% speed).
• Full brake: brake provides maximum braking torque but is ineffective at speeds greater than approximately
70%.
To configure the LV-DS for brake operation:
1. Set parameter 2I for the desired stopping time duration (1). This is the total braking time and must be set
sufficiently longer than the brake time (parameter 15H) to allow the pre-braking stage to reduce motor
speed to approximately 70%. If the stop time is too short, braking will not be successful and the motor will
coast to stop.
2. Set Brake Time (parameter 15H) to approximately one quarter of the programmed Stop Time. This sets the
time for the Full Brake stage (2).
3. Adjust the Brake Torque (parameter 15G) so that the desired stopping performance is achieved. If set too
low, the motor will not stop completely and will coast to stop by the end of the braking period.
Speed
100%
75%
0%
50%
25%
1
2
3
1: Stop time (parameter 2I)
2: Brake time (parameter 15H)
3: Coast to stop time
Time
CAUTION
When using DC brake, the mains supply must be connected to the soft starter (input terminals L1, L2,
L3) in positive phase sequence and parameter 4B Phase Sequence must be set to Positive Only.
NOTE
For loads which may vary between braking cycles, install a zero speed sensor to ensure that the soft
starter ends DC braking when the motor stops. This avoids unnecessary heating of the motor.
For more information on using the LV-DS with an external speed sensor (eg for applications with
variable load during the braking cycle), see DC Brake with External Zero Speed Sensor on page 54.
710-15797-00A – LV-DS User Manual 29/64