Eaton ZB12/XTOB BC1 Series Manual page 37

03/15 MN03407004Z-DE/EN
Target group
Abbreviations and
symbols
About This Manual
This manual applies to the ZB12/XTOB...BC1 and
ZB32/XTOB...CC1 overload relays.
It describes the overload monitoring system for the
protection of motors operating in potentially explosive
atmospheres Ex e areas.
This manual is aimed at specialist personnel who are
responsible for the installation, commissioning and
maintenance of overload relays.
Symbols used in this manual have the following meanings:
Ex e Type of protection "Increased Safety"
FIT Failure In Time
(number of dangerous failures in 10
Hardware-Fault-Tolerance
HFT
HM Highest possible setting current
MTTF Mean Time To Dangerous Failure
d
NM Lowest possible setting current
PL Performance Level
Physikalisch-Technische Bundesanstalt
PTB
(German Federal Testing Laboratory:
Accredited certification authority for devices
operated in Ex e areas)
SIL Safety Integrity Level
X indicates actions to be taken.
h Draws your attention to interesting tips and
supplementary information
9
hours)
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