Aspects Of Fusing For Armature Circuits And Field Supplies Of Dc Drives - ABB DCS 600 MultiDrive Manual

Aspects of fusing for armature circuits and field supplies of DC drives

Aspects of fusing for the armature-circuit and field supplies of DC drives
General
Unit configuration
Protection elements such as fuses or overcurrent trips
are used whenever overcurrents cannot entirely be
ruled out. In some configurations, this will entail the
following questions: firstly, at what point should which
protective element be incorporated? And secondly, in
the event of what faults will the element in question
provide protection against damage?
AC supply: public mains / plant's mains
Cabinet
3
.
.
Fig. 2.6/1 Arrangement of the switch-off elements in the
armature-circuit converter
You will find further information in publication:
Technical Guide chapter: Aspects for fusing
2
M
.
.
.
2
For field supply
see Fig. 2.6/2
3ADW000072R0501_DCS600_System_description_e_e
Conclusion for the armature supply
Due to cost saving standard fuses are used instead of the
more expensive semiconductor fuses at some applica-
tions. Under normal and stable operating conditions,
this is understandable and comprehensible, as long as
fault scenarios can be ruled out.
In the event of a fault , however, the saving may cause
very high consequential costs. Exploding power semi-
conductors may not only destroy the power converter,
but also cause fires.
Adequate protection against short-circuit and earth
fault, as laid down in the EN50178 standard, is possi-
ble only with appropriate semiconductor fuses.
ABB's recommendations
Semiconductor
fuses
DCS converter
2-Q non-regen.
Semiconductor
M
Complies with Basic Principles on:
1 – Explosion hazard
2 – Earth fault
3 – "Hard" networks
4 – Spark-quenching gap
5 – Short-circuit
6 – 2Q regenerative
Semiconductor
fuses
DCS converter
4-Q resp.
2-Q regenerative
fuses
M
yes
yes
yes
yes
yes
yes
II F 2-19