From chma@mbari.org Tue May 11 19:34 PDT 1993 Received: from hp850.mbari.org by otter.mbari.org with SMTP (16.6/15.6) id AA03238; Tue, 11 May 93 19:34:37 -0700 Return-Path: Received: by hp850.mbari.org (15.11/15.6) id AA05876; Tue, 11 May 93 19:31:15 pdt Received: by hp850.mbari.org (15.11/15.6) id AA05873; Tue, 11 May 93 19:31:10 pdt Date: Tue, 11 May 93 19:31:10 pdt From: Mark Chaffey To: kiwi@hp850.mbari.org, neji@hp850.mbari.org Subject: Wiring J-box Status: RO I've been thinking about wiring issues since our discussion this morning about the wiring/compensation system. 1. The emi filter in the J-box is much easier and simpler from a wiring point of view, especially if we decide to oil- block the cabling. A. In the case of separate EMI filters OR one filter box the main cables must go to a location where they converge and hence divide and head to each thruster. The individual cables are 3/4" to the thrusters, and other devices. The gland fittings vs. thruster connectors are about the same size in the best case and the gland fittings are much larger in the worst case (DORN fittings). So the J- box surface area requirement remains the same in the best case and actually increases if the EMI filters and connectors are remoted in the worst case. B. If we run the EMI filters in line separately we can choose to not put terminal strips in the J-box where the data and power wiring converge and run the wires straight through, branching out to each thruster with it's in line filter/connector. This makes the wiring more difficult because each filter/connector should be located fairly carefully so the wire length won't change. Each wire must be routed through one or two more gland fittings than it would otherwise. You have to unstring all the wires all the way out to EMI filter boxes to remove the VME or POWER housing connector to j-box cable from the vehicle. The J-box is used only as a "T" connection for the wires to pass through - not very efficient. If we add terminals for all the wiring in the J-box to ease wiring and debugging, the area needed grows, especially for the high current terminals needed for large loads. Including all the wiring junctions and connector matings in one (actually two, port and starboard) housings allows you to: * Use the EMI filter lugs for terminals. * Reduce the number of oil filled housings in the high current wiring from 12 to 2. * Reduce the number of gland fittings. * Save weight. * Substantially reduces the number of potential water leak points. Considering all the issues of wiring, mounting bulkhead connectors, sealing wire feed-throughs with gland fittings, compensation, the EMI filters, fabrication, etc. I think the system is simpler and better with the wiring concentrated as much as possible in as few separate spaces as can be accomplished. How do we make the J-box as small and efficient as possible and get it to fit?.............................Mark