Automation Direct Stellar SR55 Series - Derating Examples

Page D–6 Stellar
®
SR55 Series Soft Starter User Manual – 1st Ed, Rev F – 09/18/2019
Appendix D: Sizing an SR55 Soft Starter
deraTing examples
Example 1: SR55 Selection and Configuration
Step SR55 Selection
1 Application Loaded Conveyor
2 Trip Class 20
3 Duty 90%
4 In-Line or In-Delta In-Line
5 Ambient Temperature 40°C
6 Altitude 1000m
7 Full Motor Load Current 80A
8 Current Limit 4 x 80A = 320A
9 Number of Starts/Hour 10
10 Deration Factor (from Fig.2) 0.83
11 SR55 (A) = Motor FLC / Deration Factor 96A
12 Determine SR55 from Sizing Guide SR55-096
Step SR55 Configuration
1 Select Application (Auto Setup)
2 Leave Motor Current 100A (maximum) (Auto Setup)
3 Set Start Current Limit to 320A (400% of motor FLC) (Start Current Limit)
4 Set Overload Level to 88A (110% of motor FLC) (Overload Settings)
Step SR55 Alternative Configuration
1 Set Application (Auto Setup)
2 Set Motor Current to 80A (Auto Setup)
3 Warm Trip Time will be reduced to Trip Class 10 value (320A for 13s)
Example 2: SR55 Selection and Configuration
Step SR55 Selection
1 Application Agitator
2 Trip Class 10
3 Duty 90%
4 In-Line or In-Delta In-Line
5 Ambient Temperature 40°C
6 Altitude 1000m
7 Full Motor Load Current 66A
8 Current Limit 3.5 x 66A = 231A
9 Number of Starts/Hour 20
10 Deration Factor (from Fig.2) 0.66
11 SR55 (A) = Motor FLC / Deration Factor 100A
12 Determine SR55 from Sizing Guide SR55-124
Step SR55 Configuration
1 Select Application (Auto Setup)
2 Leave Motor Current 100A (maximum) (Auto Setup)
3 Set Start Current Limit to 231A (350% of motor FLC) (Start Current Limit)
4 Set Overload Level to 72A (110% of motor FLC) (Overload Settings)
Step SR55 Alternative Configuration
1 Set Application (Auto Setup)
2 Set Motor Current to 66A (Auto Setup)
3 Set Trip Class to 30 (Overload Settings)
4 Warm Trip Time will be reduced to Trip Class 10 value (231A for 17s)