Siemens MICROMASTER 440 Operating Instructions Manual page 34

2 Installation
2.4.1 General
WARNING
The inverter must always be grounded. If the inverter is not grounded correctly,
extremely dangerous conditions may arise within the inverter which could prove
potentially fatal.
Operation with ungrounded (IT) supplies
Filtered
The use of filtered MICROMASTER 4 drives on unearthed mains supplies is not
permitted.
Unfiltered
In the case of non-grounded networks, the 'Y' capacitor of the device must be
made ineffective. The procedure is described in Appendix D.
If the MICROMASTER is to remain in operation in non-grounded networks when a
ground fault occurs during the input or output phase, an output reactor must be
installed.
Operation with Residual Current Device (Frame Sizes A to F)
If an RCD (also referred to as ELCB or RCCB) is fitted, the MICROMASTER
inverters will operate without nuisance tripping, provided that:
A type B RCD is used.
The trip limit of the RCD is 300 mA.
The neutral of the supply is grounded.
Only one inverter is supplied from each RCD.
The output cables are less than 50 m (screened) or 100 m (unscreened).
NOTE
The residual current operated circuit-breakers used must provide protection against
direct-current components in the fault current and must be suitable for briefly
suppressing power pulse current peaks. It is recommended to protect the
frequency inverter by fuse separately.
The regulations of the individual country (e.g. VDE regulations in Germany)
and the regional power suppliers must be observed!
34
MICROMASTER 440 Operating Instructions
6SE6400-5AW00-0BP0
Issue 10/06