Siemens S5-135U/155U - Manual (Page 94)

4-28
System Manual
C79000-G8576-C199-06
You must remove the power supply unit if you:
S
change the jumper settings
S
send the power supply unit in for repair.
!
Caution
Power supply units may only be removed when power is switched off.
If 230 V I/O modules are fitted, you must ensure before removing the power
supply unit that the subrack is
grounded when the PSU is removed, or the
230 V supply for these modules is switched off.
When the power supply unit is removed, the connection between backup
battery and backplane bus remains; this ensures backup of the user program.
Proceed according to the following steps to remove the power supply unit:
Step Action
1 Switch the Power switch off
(standby On/Off).
2 Disconnect the power supply unit form the AC line voltage.
3 Detach the connections of all leads from the front terminals.
4 Important
!
p
Before pulling out the PSU, wait at least 8 minutes after switching off the
power so that the electrolytic capacitors can discharge.
5 Slacken the fixing screws on the left and right of the PSU.
6 Pull the PSU out.
There are grips to pull it out under the unlock fan openings.
Removing the
Power Supply Unit
When to Remove
the PSU
How to Remove
the PSU
Central Controllers and Expansion Units Power Supply Units