Operating instructions

Operation with up to three supply inverters

MICROMASTER 420 / 440 – DC link coupling between several

Frequency inverters

A&D SD Page 32/32

5.9 Risk for the connected frequency inverters in the case of a DC

link short-circuit

When a short-circuit or ground fault occurs in the DC link (in the DC link

coupling or within a frequency inverter), there is a risk that all of the

frequency inverters, connected to the DC link, will be destroyed. This is the

reason that when the drive system is engineered, this aspect should be

carefully taken into account. The number of frequency inverters within a DC

link group should be kept as low as possible.

5.10 Operation on IT line supplies

The frequency inverter without integrated EMC filter can also be used in a

DC link group connected to an IT line supply. In this case the Y capacitor of

the frequency inverter should be removed. A description is provided in the

Operating Instructions of the frequency inverter.