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Parameters
In addition to the parameter below, the parameters of the starting mode "torque control"
(Page 137) also apply.
Parameters
Current limiting value
8.1.7
Direct-on-line starting
Operating principle
The motor is switched on immediately without closed-loop control in the direction of rotation
(right/CW = line phase direction). Starting takes place without being influenced by Current
limiting by the 3RW55 or 3RW55 Failsafe soft starter, for example. Current limiting is only
activated when 7.5 times the rated current of the soft starter is exceeded to avoid an overload.
If the starting mode "Direct" is set, a fast voltage ramp of approx. 100 ms will effected on a start
command. This limits the inrush current of the motor. After the 3RW55 or 3RW55 Failsafe soft
starter has detected that the motor has ramped up, the bypasses are activated. This type of
starting is equivalent to the starting behavior with a contactor.
Setting via 3RW5 HMI High Feature
• Menu: "Parameters > Soft Starter > Parameter set 1 / 2 / 3 > Start settings > Starting mode >
Direct"
• Access protection to the 3RW5 HMI High Feature is not active or has been reset.
8.1.8
Motor heating
Operating principle
The starting mode "motor heating" heats up the motor. No startup takes place. The motor
heating remains switched on for as long as the control command "Motor CW" or "Motor CCW" is
present.
SIRIUS 3RW55 and 3RW55 Failsafe Soft Starters
Equipment Manual, 02/2022, A5E35630887002A/RS-AF/006
Description
Set the current limiting value, as a factor of the rated motor current, to the maximum current
required during startup. If the set current limiting value has been reached, the motor voltage
is reduced or controlled by the 3RW55 or 3RW55 Failsafe soft starter to prevent the current
from exceeding the set current limiting value.
Select a minimum current limiting value that is high enough to ensure that the torque gener‐
ated in the motor is sufficient to accelerate the motor to nominal speed. 3 to 4 times the value
of the motor's rated operational current I
(Identical to the parameters in chapters Soft starting with voltage ramp and current limiting
(Page 140) and Automatic parameterization (Page 132))
•
Factory setting: 400%
•
Setting range: 125 ... 800%
•
In steps of: 1%
can be assumed as typical here.
e
Functions
8.1 Start-up
143
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