Baumuller b maXX 3000, Инструкция по эксплуатации

Страница: 26 / 220

Operating conditions
Instruction handbook b maXX BM3000, BM3200, BM3300
Document no. 5.11018.11 Baumüller Nürnberg GmbH
26
of 218
3.3
3.3 Operating conditions
3.3.1 System types
There is a differential structure of current supply networks and it is distinguished between
three basic types, referring to their grounding, which is accordant to DIN VDE0100 part
300 and accordingly to IEC 60364:
m In a TN-system one point is directly grounded (main ground). The cabinet of the elec-
trical installation is connected via protective conductors and accordingly PE-conduc-
tors with this point.
m In a TT-system a point is directly grounded (main ground). The cabinet of the electric
installation is connected to ground connections, which, however, are separated from
the main ground.
m In an IT-system there is no direct connection between active conductors (L1, L2, L3,
N) and grounded parts (PE). The cabinets of the electrical installation are grounded.
The separation is reached, by the use of an isolating transformer or with the use of an
independent current source (generator, battery).
If there is an adequate low-impedance grounding within the TN- or the TT-network, then
a line-side fuse is activated. A high-impedance grounding does not activate the fuse, so
that the ground currents (error current) can be potentially dangerous. For this reason, cir-
cuit breakers are used for the error current monitoring.
At a short-circuit to ground, no ground current can flow and the line-side fuses cannot be
activated, by which the operation can be kept up. Only a second short-circuit to ground at
another phase would cause an current error, which can trigger a fuse. In order to detect
the first short-circuit to ground an insulation monitor and for the second short-circuit to
ground, a current error monitoring, are necessary.
Supported system
types
NOTICE!
The operation of the BM3000 devices is possible with all power supply networks.
The operation of the BM3200, BM3300 devices is possible with TT - and TN -net-
works.
The common network types in the USA are differentiate clearly from the European
networks. Besides the Solidly Grounded Wye, which is similar to the TN-S-system,
there is also a Corner Grounded Delta (this differs to the description in the IEC). The
BM3200, BM3300 may not be operated here.
An operation with DC-link connection and use of a active mains rectifier is forbidden.