Access Power Solutions Installation and Operation Guide (APS6-300/500 and APS12-300 Series)
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IPN 997-00012-49G May 2013
Step 4 - Check ac discrimination
Each rectifier has two internal fast-acting fuses. Under certain internal fault
conditions these fuses will blow.
If there is insufficient discrimination between these fuses and any upstream ac
supply-disconnect device then the upstream ac supply-disconnect device will
operate before a rectifier fuse blows. This will disconnect the ac supply to all
rectifiers.
1
Check the time-current (tripping) curve(s) of all ac supply-disconnect device(s)
upstream of the APS with the following curve for the rectifier fuses.
Refer to the manufacturer's data for tripping curves.
Time-Current Curve
(minimum and
maximum) for rectifier
internal fuses (IEC
60127-2).
Source: Schurter SP 5x20
Pigtail data sheet.
2
No action is required if the time-current curves of the upstream ac
supply-disconnect devices are entirely to the right of the curves for the rectifier
fuses.
3
If the curve of an upstream ac supply-disconnect device crosses the curve for the
rectifier fuse there may not be adequate discrimination.
If necessary, replace the upstream ac supply-disconnect device to achieve
adequate discrimination. Or, contact your Eaton dc product supplier for advice
(see Worldwide Support on page
