Siemens SIRIUS 3RW55 Manual page 88

Functions
7.2 Start-up
Parameters
Parameters
Starting torque
Limiting torque
Ramp-up time
Maximum starting
time
Breakaway time
Breakaway voltage
88
Description
The starting torque determines the switch-on torque of the motor. A lower
starting torque results in a lower switch-on torque and a lower starting current.
Select a sufficiently high starting torque to ensure that the motor starts
immediately and smoothly when the start command is issued to the soft
starter.
Factory setting: 10 %
•
Setting range: 10 ... 100 %
•
Increment: 5%
•
The limiting torque value specifies the maximum torque to be generated in the
motor during run-up. This value also functions as an adjustable torque limit.
The parameter value should be set to approx. 150% to start the motor. It
should be high enough to ensure that the motor does not falter during run-up.
This ensures that enough acceleration torque is generated throughout the
motor run-up phase. The rated torque of the motor servers as the reference
value.
Limiting torque > Starting torque
Factory setting: 150 %
•
Setting range: 20 ... 200 %
•
Increment: 5%
•
The length of the ramp-up time determines the time in which the starting
torque is increased to the
limiting torque. This has an influence on the motor's acceleration torque which
drives the load during the ramp-up operation. A longer ramp-up time results in
a shorter acceleration torque across the motor ramp-up time. The motor
therefore runs up more slowly and smoothly.
The actual motor starting time is load-dependent and can differ from the
parameterized ramp-up time. If the starting time ends before the motor has
completely run up, the torque is limited to the set limiting torque until the soft
starter recognizes the run-up process and closes the internal bypass contacts.
If parameter value "0" is set, the motor is switched on with a ramp-up time of
approx. 100 ms.
Factory setting: 10 s
•
Setting range: 0 ... 360 s
•
Increment: 0.1 s
•
This time determines the period after which the drive must have completed its
run-up. If the drive is not operating under rated service conditions after the
specified interval has expired, the current limiting is interrupted and the motor
is switched to 100%.
Maximum starting time ≥ ramp-up time.
Factory setting: 0 s
•
Setting range: 0 ... 1 000 s
•
Increment: 0.1 s
•
See Breakaway pulse for startup functions (Page 94)
SIRIUS 3RW55 soft starter
Manual, 08/2018, A5E35630887002A/RS-AB/002