Specifications

Softstart UK Operation
The STOP button on the keypad is always enabled.
Control via the serial communication network is always enabled in local control mode, and can be enabled or
disabled in remote control mode (parameter 6B Comms in Remote). Control via the serial communication
network requires an optional communication module.
• Using the Soft Starter to Control a Motor
To soft start the motor, press the START button on the keypad or activate the Start remote input. The motor
will start using the start mode selected in parameter 2A.
To stop the motor, press the STOP button on the keypad or activate the Stop remote input. The motor will
stop using the stop mode selected in parameter 2H.
To reset a trip on the soft starter, press the RESET button on the keypad or activate the Reset remote input.
To stop the motor with a coast to stop, regardless of the setting of parameter 2H Stop Mode, press the local
STOP and RESET buttons at the same time. The soft starter will remove power from the motor and open the
main contactor, and the motor will coast to stop.
7.5. Soft Start Methods
Soft starters offer a variety of methods to control motor starting. Each soft start method uses a different primary
control parameter.
• Constant Current
Constant current is the traditional form of soft starting, which raises the current from zero to a specified level
and keeps the current stable at that level until the motor has accelerated.
Constant current starting is ideal for applications where the start current must be kept below a particular level.
Current
(%motor full load current)
700%
600%
500%
300%
100%
400%
200%
10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
1
3
2
1: Initial current (parameter 2C)
2: Current limit (parameter 2B)
3: Full voltage current
Rotor speed (% full speed)
• Current Ramp
Current ramp soft starting raises the current from a specified starting level (1) to a maximum limit (3), over an
extended period of time (2).
Current ramp starting can be useful for applications where:
• the load can vary between starts (for example a conveyor which may start loaded or unloaded). Set the
initial current (parameter 2C) to a level that will start the motor with a light load, and the current limit
(parameter 2B) to a level that will start the motor with a heavy load.
• the load breaks away easily, but starting time needs to be extended (for example a centrifugal pump where
pipeline pressure needs to build up slowly).
• the electricity supply is limited (for example a generator set), and a slower application of load will allow
greater time for the supply to respond.
Current
(%motor full load current)
700%
600%
500%
300%
100%
400%
200%
1
4
3
2
1: Initial current (parameter 2C)
2: Start ramp time (parameter 2D)
3: Current limit (parameter 2B)
4: Full voltage current
Time
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