Technical information
Safety instructions
1-10
1070 080 059-101 (2001.04) GB
DANGEROUS ELECTRICAL VOLTAGE
Danger of life through insufficient protective conductor system!
The medium-frequency inverters must be connected to the protec-
tive earthing (PE) circuit of the system. Please ensure that the cross-
sectional area of cables used for protective conductor wiring is suffi-
ciently large. The electrical continuity of the protective earthing cir-
cuit must be verified in accordance with EN 60204 Part 1.
DANGEROUS ELECTRICAL VOLTAGE
Any residual current devices used on the mains side of the MF invert-
ers to protect persons getting into direct or indirect contact must be
of type B. As per IEC 60 755, these devices must also be capable of
safely detecting possible residual currents of 1 kHz frequency.
DANGEROUS ELECTRICAL VOLTAGE
MF inverters may be operated in earth neutral systems only.
Protective grounding is the only protective measure permitted as per
prEN 50 178 (DIN VDE 0160)!
Operation in systems with ordinary residualcurrent circuitbreakers
is not permitted because of the risk that residual currents may flow
from the intermediate circuit to earth and back into the system
without tripping the RCCB.
In the case of operation with an isolating transformer, singlesided
grounding of the intermediate circuit is not permitted.
DANGEROUS ELECTRICAL VOLTAGE
Operation in unbalanced networks (only one network phase
grounded) is not permitted.
. Note: It is recommended that the whole welding system be operated
within a separate welding power network.
The MF inverters are approved for operation in grounded systems (TT or TN
systems). For operation in non-grounded systems (e.g., IT systems), an
isolation transformer with its center point of earth potential in secondary cir-
cuit must be used.