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Fast Transfer Switching
Sensitive loads in industrial processes are often configured with a secondary primary feed from the utility for
backup and reserve power. For sectors such as oil & gas, slow transfer times from traditional switching solutions
result in motor stoppages and lost production time while processes are brought back on-line.
The high closing and opening speeds of the ISM15_Shell_2 series allow for a packaged solution. The VCB_FTS
system is comprised of specially selected ISM15_Shell_2 breakers, control modules with a faster command
recognition speed, and optional automatic transfer relays.
Transfer speed can be delineated by two transition types:
1. Closed transition - the backup power line is connected by closing the breaker before the main line is interrupted
(make before break).
2. Open transition - the backup power line is connect by closing the breaker after the main line is interrupted (break
before make).
The timing of the system can therefore be broken down by the following table, using the SEL-451 relay as an
example of total timing calculation:
Product Parameters
Designation
Response Time
ISM15_Shell_2 opening time (including CM)
Topen
12 ms
ISM15_Shell_2 interrupting time (including CM)
Tinterrupt
20 ms
ISM15_Shell_2 closing time (including CM)
Tclose
26 ms
SEL-451 open phase detection logic trip time
Tsel451
10 ms
Closed transition with SEL-451 open phase detec-
tion logic trip time
T Tclose
36 ms
Open transition with SEL-451 open phase detec-
tion logic trip time
T Topen
48 ms
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Summary of Contents for ISM Shell_2 Series
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Page 7: ...7 Introduction 1...
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Page 13: ...13 Receiving Handling and Storage 2...
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Page 37: ...37 Switching and Control Functions 4...
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Page 45: ...45 Signalling 6...
Page 49: ...49 Special Applications Fast Switching 6...
Page 53: ...53 Product Line 7...
Page 55: ...55 Dimens ions and Weights 8...
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Page 62: ...62 Circuit Diagrams 9...
Page 63: ...63 ISM15_Shell_2 with CM_1501_01 9...
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Page 66: ...66 Technical Data 10...
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Page 72: ...72 Regulations and Ambient Conditions 11...
Page 74: ...74 Legal Information 12...
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