SIEMENS
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Siemens IC 10 · 2017
SIRIUS 3RW Soft Starters
3RW30, 3RW40 for Standard Applications
3RW30
Accessories
6
■
More information
Application examples for normal starting (CLASS 10)
1)
The mass inertia of the fan is <10 times the mass inertia of the motor.
Note:
These tables present sample set values and device dimensions.
They are intended only for the purposes of information and are
not binding. The set values depend on the application in
question and must be optimized during commissioning.
The soft starter dimensions should be checked where necessary
with the help of Technical Assistance.
Configuration
The 3RW solid-state motor controllers are designed for easy
starting conditions. In the event of deviating conditions or
increased switching frequency, it may be necessary to choose a
larger device.
If necessary, an overload relay for heavy starting must be
selected where long starting times are involved. PTC sensors are
recommended.
No capacitive elements are permitted in the motor feeder
between the SIRIUS 3RW soft starter and the motor (e.g. no
reactive-power compensation equipment). In addition, neither
static systems for reactive-power compensation nor dynamic
PFC (Power Factor Correction) must be operated in parallel
during starting and ramp-down of the soft starter. This is
important to prevent faults arising on the compensation
equipment and/or the soft starter.
All elements of the main circuit (such as fuses, controls and
overload relays) should be dimensioned for direct starting,
following the local short-circuit conditions. Fuses, controls and
overload relays must be ordered separately. Please observe the
maximum switching frequencies specified in the technical
specifications.
Note:
When three-phase motors are switched on, voltage drops occur
as a rule on starters of all types (direct-on-line starters, wye-delta
starters, soft starters). The infeed transformer must always be
dimensioned such that the voltage dip when starting the motor
remains within the permissible tolerance. If the infeed
transformer is dimensioned with only a small margin, it is best for
the control voltage to be supplied from a separate circuit
(independently of the main voltage) in order to avoid the
potential switching off of the soft starter.
Schematic circuit diagram of power electronics
A bypass contact system is already integrated in the 3RW30 soft starter
and therefore does not have to be ordered separately.
Status graphs
Manual for SIRIUS 3RW30/40
In addition to relevant configuration, commissioning, and service
information, the manual also contains example circuits and
technical specifications for all devices,
see
.
Normal starting CLASS 10
(up to 20 s with 300%
I
n Motor
, one start per hour)
The soft starter rating can be selected to be as high as the rating of the motor used
Application
Conveyor belts
Roller conveyors
Compressors
Small fans
1)
Pumps
Hydraulic pumps
Starting parameters
• Voltage ramp and current
limiting
-
Starting voltage
%
70
60
50
40
40
40
-
Starting time
s
10
10
20
20
10
10
NSB0_01940
T1
L1
T2
L2
T3
L3
NSB0_01941
t
t
U
U
U
N
S
ON
13/14
t
R on
t
R on
© Siemens AG 2016