Planning The Electrical Installation; Contents Of This Chapter; Checking The Compatibility Of The Generator; Protecting The Generator Winding And Bearings - ABB ACS800 Series Hardware Manual

Planning the electrical installation

Contents of this chapter

This chapter contains the instructions that you must follow when selecting the
generator, cables, protections, cable routing and way of operation for the converter
system.
Note: The installation must always be designed and made according to applicable
local laws and regulations. ABB does not assume any liability whatsoever for any
installation which breaches the local laws and/or other regulations. Furthermore, if
the recommendations given by ABB are not followed, the converter may experience
problems that the warranty does not cover.

Checking the compatibility of the generator

See chapter
data.

Protecting the generator winding and bearings

The output of the converter comprises – regardless of output frequency – of pulses
of approximately 1.35 times the mains network voltage with a very short rise time.
This is the case with all converters employing IGBT converter technology.
The voltage of the pulses can be almost double at the generator terminals,
depending on the generator cable properties. This in turn can cause additional
stress on the generator insulation.
Modern variable speed converters with their fast rising voltage pulses and high
switching frequencies can cause current pulses through the generator bearings
which can gradually erode the bearing races.
The stress on generator insulation is reduced by using du/dt filters. Du/dt filters also
reduce bearing currents.
To avoid damage to generator bearings, insulated N-end (non-driven end) bearings
and output filters from ABB must be used. In addition, the cables must be selected
and installed according to the instructions given in this manual. These types of filters
are included in the ACS800-67 converter as default:
• du/dt limitation (protects generator insulation system and reduces bearing
currents).
Technical data for the converter ratings and the generator connection
Planning the electrical installation
57