Removing The Power Supply Unit - Siemens S5-155U System Manual

Removing the power supply
unit
When to remove the PSU
How to remove the PSU
System Manual
C79000-B8576-C199-03
You must remove the power supply unit if you:
• •
change the jumper settings;
• •
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 from the AC line
voltage.
3 Detach the connections of all leads from the front
terminals.
4 Important
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.
Power Supply Units
4 - 31
4