904217 – 2018-11
117
Subject to change.
A
pp
endix
8.4
Glossary
The operating manual contains a number of technical terms and abbreviations that describe
engine-related and electrical matters. These are explained in brief here:
ESC
:
Electricity supply company; regional contact partner for all questions relating to connecting
the genset to an existing power network.
Isolation monitoring:
Isolation monitoring is used in IT networks to monitor the isolation of the generator from
the earth. It permanently monitors the phase or phases to the earth and is triggered if an
isolation threshold value is fallen below. One of the following reactions can be configured for
this:
The genset is stopped immediately in the event of a fault.
The operator is alerted both visually and audibly of the fault. The genset can continue
to be operated in an emergency, but is stopped immediately as soon as another fault
occurs.
IT network:
from the French
Isolé Terre
; low-voltage network in which all live components are assembled
isolated from the earth. This means that there is no voltage potential between a phase
conductor of the genset (generator) and the earth. If a person who is also touching
the earth touches a phase conductor, no current flows because no circuit is closed. The
isolation between the generator winding and the earth is permanently monitored (isolation
monitoring).
TN network:
from the French
Terre Neutre
; low-voltage network in which the star point of the generator
winding is connected to the earth. If a phase is present on a metal housing in the event of a
fault, the short circuit trips a fuse that deactivates the circuit. A distinction is made between
the following TN networks, according to the configuration of the protective conductor:
TN-C system (French
Terre Neutre Combiné
): A PEN conductor performs a dual role as a
protective conductor PE (
protective earth)
and as a neutral conductor N
(neutral)
.
TN-S system (French
Terre Neutre Séparé
): The protective conductor PE and the neutral
conductor N are routed separately from the genset to the electrical equipment.
TN-C-S system: A combination of a TN-C and TN-S system, with the TN-C mostly being
realised on the supply side (e.g. genset) and the TN-S on the consumer side.
With TN-C systems it must be remembered that there is a danger to life as soon as the PEN
conductor is disconnected in the system. As the circuit is not closed in this case, it also
cannot be deactivated by a fuse. For example, if a phase is present on the genset’s metal
housing, there is a risk to the life of anyone touching the metal housing: The touch closes the
circuit and the current flows via the person touching.
EN