10
Site Preparation Guide • August 2011
Note –
Power for the optional –48-VDC power configuration is supplied by a
centralized DC power plant instead of the AC power source in the cabinet. Refer to
the associated manufacturer’s documentation for specific DC power source
requirements.
Consider the following information when preparing the array’s installation site:
■
Protective ground—Site wiring must include a protective ground connection to
the AC power source or the optional –48-VDC power source.
Note –
Protective ground is also known as safety ground or chassis ground.
■
Circuit overloading—Power circuits and associated circuit breakers must provide
sufficient power and overload protection. To prevent possible damage to the
array, isolate its power source from large switching loads (such as air-
conditioning motors, elevator motors, and factory loads).
■
Power interruptions—The controller tray can withstand the following applied
voltage interruptions (with or without an integrated uninterruptible power
supply [UPS]):
■
Input transient—50 percent of the nominal voltage
■
Duration—One-half cycle
■
Frequency—Once every 10 seconds
■
Power failures—If a total power failure occurs, the controller tray automatically
performs a power-on recovery sequence without operator intervention after
power is restored.
Note –
When a power failure occurs, the controller tray uses battery power to back
up the data that is in cache.
