08 OPERATION
3BHS842007 E01 REV C
ACS6080
USER MANUAL
170/238
8.7
Grounding switch and door locking system
The grounding switch of the CBU is a protection device that enables safe
access to the medium voltage units of the drive.
Figure 8-6 CBU grounding switch in ungrounded (A) and grounded (B)
The switch is electromechanically interlocked with a discharge monitoring
circuit that prevents the switch from closing when the DC-link capacitors
are still charged.
Grounding the drive is only possible after the main power supply has been
disconnected and the DC link has discharged. The yellow lamp lights up
when the DC-link voltage is below 50 V(DC).
When the grounding switch is in position grounded, the door safety
switches of the medium voltage units are released and the doors can
be opened.
(1) Grounding switch in ungrounded
position (A)
(2) Grounding switch in grounded
position (B): When the switch is in
grounded position, the DC link of
the drive is connected to the
ground busbar of the drive.
(3) White illuminated pushbutton: DC
link is grounded: Lights up to
indicate that the drive is grounded
and that the locking bar (see 1 in
Fig. 8-7) of each medium voltage
unit can be moved to the unlocked
or locked position.
(4) Yellow illuminated pushbutton:
grounding switch unlocked
• Lights up to indicate that the
grounding switch can be turned
to the ungrounded or grounded
position.
• Press the yellow pushbutton to
turn the grounding switch to the
desired position.
A
B
1
3
4
3
4
2
