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Prerequisites
1 - 3
Siemens AG
SPR8-125.061.02
Page 3 of 4
POLYMOBIL Plus
Medical Engineering
Rev. 01
01.00
TD SD 24
When working on the open system, there is the danger of
Electric shock !
•
The capacitor bank can still be charged.
Do not attempt to work on the system while this condition exists.
•
After switching off the system, approximately 450 V may still be
present in the system ; even after disconnecting the line voltage
plug. Within 10 minutes this voltage will drop to approximately
10 V.
•
Always measure the actual voltage present with the DVM at test
points -VCC and + VCC on the D 960 inverter board or (more
accessible) on the D 970 capacitor board at the + connection
point of capacitor C3 and on the right side of fuse F3 (refer to
Fig. 1).
•
LED’s V1 ... V10 on D 970 go out at a significantly higher voltage
level and therefore they are not reliable safety indicators.
•
If a fuse on the D 970 has responded, high voltage may still be
present at the affected capacitor even after a prolonged period
of time.
•
The capacitor discharging circuit utilizes the D925 board, CS
and LS relays. If connectors X3 or X9 on D 925 or D 950 are not
inserted or if there is a defect in the circuit, the C-bank will not
discharge.
This can cause life-threatening voltage to be present in the
system even after a prolonged period of time.
•
Refer also to chapter "Replacing the capacitor bank".
Fig. 1
VCC
+ -
R5
C1
R3
R4
WARNING