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Parameters
NOTICE
Damage to property due to DC braking
DC braking causes a higher current load and motor-specific noises and vibrations.
This can lead to premature failure of motor bearings. It may be necessary to overdimension the
3RW55 soft starter.
Parameters
Stopping time
DC braking torque
DC braking delay
8.2.6.2
Dynamic DC braking without contactor
Operating principle
Braking is performed in 2 phases. In the first phase the motor is braked by controlled DC braking
pulses. In the second phase, the motor is brought to a standstill with a constant DC braking. Use
DC braking if a uniformly long braking time is required.
To guarantee a premature cancellation of the braking process, the "External motor standstill
detection (Page 162)" or "Sensorless motor standstill detection (Page 162)" function can be used
to detect motor standstill before the stopping time has elapsed. As motor protection, the use of
the thermistor motor protection with temperature sensor (Page 169) is recommended.
Application
• Stopping in applications with small mass inertia (centrifugal masses): J
• If an electrical braking process without braking contactor is required.
SIRIUS 3RW55 and 3RW55 Failsafe Soft Starters
Equipment Manual, 02/2022, A5E35630887002A/RS-AF/006
Description
On expiry of the stopping time, the DC braking procedure is automatically terminated. The
setting "0 s" causes the motor to shut down immediately without DC braking.
•
Factory setting: 10 s
•
Setting range: 0 ... 360 s
•
In steps of: 0.1 s
The motor's braking force can be set with the magnitude of the DC braking torque.
•
Factory setting: 50%
•
Setting range: 20 ... 100%
•
In steps of: 5%
The DC brake delay starts when the motor OFF command ("Motor CW" and "Motor CCW" = 0)
is detected. The motor coasts freely while the DC brake deceleration time elapses. After the DC
braking delay has elapsed, DC braking is started.
The motor brakes by free coasting, which means less energy is required for the following DC
braking. This reduces the risk that the 3RW55 soft starter may overheat during DC braking.
This parameter is used for "Stopping mode" and ignored for "Alternative stopping mode".
•
Factory setting: 0 s
•
Setting range: 0 ... 360 s
•
In steps of: 0.1 s
Functions
8.2 Run-down
≤ J
load
motor
157
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