Siemens 420 manual General, Operation with ungrounded IT supplies, Operation with long cables

2 Installation Issue 07/04

2.4.1General

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

It is not permissible to connect MICROMASTER 4 drive converters equipped with integrated filter to non-grounded line supplies.

If connected to non-grounded line supplies, the 'Y' capacitor must be disabled in the device. The procedure is described in Attachment B.2.

The MICROMASTER operates on non-grounded line supplies and remains operational if an input or output phase is connected to ground. In this particular case, an output reactor must be installed.

Operation with Residual Current Device

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 300mA. The neutral of the supply is grounded.

Only one inverter is supplied from each RCD.

The output cables are less than 50m (screened) or 100m (unscreened).

Operation with long cables

All inverters will operate at full specification with cable lengths up to 50 m screened or 100 m unscreened.

When using output reactors as shown in Catalog DA 51.2, the following cable lengths are possible for all of the types of construction/sizes:

Shielded:	200 m
Non-shielded:	300 m

MICROMASTER 420	Operating Instructions
28	6SE6400-5AA00-0BP0