Normal Or Heavy Starting; Application Examples For Normal Starting (Class 10); Application Examples For Heavy Starting (Class 20) - Siemens SIRIUS 3RW44 System Manual

2.2

Normal or Heavy Starting

Selection criteria

2.2.1 Application Examples for Normal Starting (CLASS 10)

Normal starting CLASS 10 (up to 20 s with 350 % I
The soft starter's output can be the same as that of the implemented motor
Application
Starting parameters
• Voltage ramp and current
limiting
- Start voltage
- Starting time
- Current limit value
• Torque ramp
- Start torque
- End torque
- Starting time
• Breakaway pulse
Stopping mode

2.2.2 Application Examples for Heavy Starting (CLASS 20)

Heavy starting CLASS 20 (up to 40 s with 350 % I
The selected soft starter must have a power class that is 1 class higher than that of the implemented motor
Application
Starting parameters
• Voltage ramp and current
limiting
- Start voltage
- Starting time
- Current limit value
• Torque ramp
- Start torque
- End torque
- Starting time
• Breakaway pulse
Stopping mode
SIRIUS 3RW44 System Manual
GWA 4NEB 535 2195-02 DS 04
To properly dimension a soft starter, it is important to know and take into account
the starting time (normal or heavy starting) of the application. Long starting times
mean a higher thermal load for the thyristors of the soft starter. The 3RW44 soft
starters are designed for continuous operation under normal starting conditions
(CLASS 10), an ambient temperature of 40 degrees Celsius and a fixed
switching frequency. You can also find these values in Chapter 10.3.2 "Technical
Data Power Unit". If deviations from these data occur, it may be necessary to
overdimension the soft starter. Using the Win Soft Starter selection and
simulation program from SIEMENS, you can enter your application data and
requirements, and it will determine the optimum soft starter dimensions for your
application (refer to Chapter 10.3.8 "Accessories" software).
Note
The adequate size of the SIRIUS 3RW44 soft starters must be selected on the
basis of the motor rated current
(Rated current
soft starter
),
n motor
Conveyor belts Powered roller
conveyors
% 70 60
s 10 10
Deactivated Deactivated
60 50
150 150
10 10
Deactivated (0 ms) Deactivated (0 ms) Deactivated (0 ms) Deactivated (0 ms) Deactivated (0 ms) Deactivated (0 ms)
Soft stopping Soft stopping
),
n motor
Stirrers
% 30
s 30
4 x I
M
30
150
30
Deactivated (0 ms)
Coasting down
≥ motor rated current).
Compressors Small ventilators Pumps
50 30
10 10
4 x I 4 x I
M M
40 20
150 150
10 10
Coasting down Coasting down
Centrifugal machines
30
30
4 x I
M
30
150
30
Deactivated (0 ms)
Coasting down
Configuration Instructions
Hydraulic pumps
30 30
10 10
Deactivated Deactivated
10 10
150 150
10 10
Pump stop Coasting down
Milling machines
30
30
4 x I
M
30
150
30
Deactivated (0 ms)
Coasting down or DC braking
2-3