Access Power Solutions Installation and Operation Guide (APS6-300/500 and APS12-300 Series)
88
Copyright © 2007-2013 Eaton Corporation. All Rights Reserved.
IPN 997-00012-49G May 2013
Primary Transient Protection
Primary transient protection must be considered at all sites. Eaton recommends primary
transient protection on the incoming ac supply either at the main ac switchboard or
sub-switchboard.
In the absence of sufficient information, primary transient protective devices with a minimum
repeat strike rating of 100kA (8/20μs wave shape) are recommended.
In addition, primary transient protection must be coordinated with downstream secondary
transient protection via suitably rated surge decoupling coils. These should have been specified
as part of the transient protection plan for the site. If no surge decoupling coils were specified,
then air-core 15
H surge decoupling coils are suitable.
Installation
Install the transient protection according to the following diagram.
Supply transformer
Building entrance
Main switchboard
Fuses
Primary transient protection (refer to
text for rating)
Building earth/ground busbar
Primary/secondary surge decoupling
coils (4, refer to text for rating)
AC sub-switchboard or APS dc
power system
Secondary transient protection
MOVs (3, phase-neutral, refer to text
for rating)
Spark gap (neutral-earth)
Switchboard earth/ground busbar
Secondary/Tertiary surge decoupling
coils (4 x 11
H minimum)
Access Power Rectifiers
