From colu@mbari.org Wed Sep 29 09:37 PDT 1993 Received: from hp850.mbari.org by otter.mbari.org with SMTP (16.6/15.6) id AA14965; Wed, 29 Sep 93 09:37:13 -0700 Return-Path: Received: by hp850.mbari.org (15.11/15.6) id AA03187; Wed, 29 Sep 93 09:34:13 pdt Received: by hp850.mbari.org (15.11/15.6) id AA03168; Wed, 29 Sep 93 09:33:35 pdt From: Luke Coletti Subject: GFI. To: newrov@hp850.mbari.org Date: Wed, 29 Sep 93 9:33:34 PDT Cc: colu@hp850.mbari.org (Luke Coletti) Mailer: Elm [revision: 66.25] Status: RO A recent circuit enhancement was made that now prevents the Ground Fault Interrupter (GFI), from keeping vehicle power ON if no current is drawn during the charge cycle. The GFI as well limits if excess current is drawn at the end of the charge cycle. Detection of these two events safe guards the DC contactors and the vehicle itself. The purpose of this note is to provide the users of the GFI an insight into the causes of a "OVER/UNDER CHARGE ALARM" lamp indication on the the front panel. Possible reasons for an under charge condition could be failed charge transistors, open tether or failed current sensors. Possible reasons for an over charge condition could be a shorted tether or excess current draw from the on board "hotel systems". It should be noted as well that as more systems are added to the vehicle it may become necessary to increase the over current threshold. There have been no problems to date with the GFI but this enhancement should make the unit more robust. Luke