Liebert Static Transfer Switch 2, Installation, Operation & Maintenance Manual

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106 Operating the LED Display STS2
To return to normal mode:
1. Verify that the LEDs for Source 2 are on, indicating that the source is supplying power and is
operating within acceptable tolerances.
2. Insert key in the CB2 breaker interlock.
3. Rotate key to retract interlock.
4. Close source input breaker CB2.
The LED for CB2 is turned on.
5. Close output breakers CB3 and CB3A (if supplied).
The LEDs for CB3 and CB3A (if supplied) turn on.
6. Open bypass breaker CB5.
The LED for CB5 is turned off.
7. Rotate keys in CB5 interlock to extend interlock.
8. Remove the proper key from CB5 interlock and insert it in CB1 breaker interlock.
9. Rotate key to retract CB1 breaker interlock.
10. Close source input breaker CB1.
The LED for CB1 is turned on.
11. Verify that the output LED is lit.
14.2.4 Normal System Shutdown
The STS2 can be shut down from either the static switch mode or the bypass mode.
Shutdown in Static Transfer Switch Mode
When the Static Transfer Switch is operating on static transfer switch mode (not main-
tenance bypass mode):
1. Turn off the load equipment per manufacturer’s recommendations.
2. Open CB3 to turn off the static switch output.
• Open CB3A if the static transfer switch is a redundant output configuration.
The LEDs for CB3 and CB3A (if supplied) and the output (OUT) are turned off.
3. Open the input switches CB1 and CB2.
The LEDs for CB1 and CB2 are turned off.
4. To completely de-energize the unit, turn OFF the power to both inputs to the STS2.
Shutdown in Maintenance Bypass Mode
When the Static Transfer Switch is operating on bypass:
1. Turn off the load equipment per manufacturer’s recommendations.
2. Open the bypass switch (CB4 or CB5) to turn off the static transfer switch output.
The LED for the bypass switch is turned off.
The output (OUT) LED is turned off.
3. To completely de-energize the unit, turn OFF the power to both inputs to the STS2.