From meed@mbari.org Tue Mar 30 17:00 PST 1993 Received: from hp850.mbari.org by otter.mbari.org with SMTP (16.6/15.6) id AA15930; Tue, 30 Mar 93 17:00:34 -0800 Return-Path: Received: by hp850.mbari.org (15.11/15.6) id AA28459; Tue, 30 Mar 93 16:57:49 pst Received: by hp850.mbari.org (15.11/15.6) id AA28446; Tue, 30 Mar 93 16:57:41 pst From: Ed Mellinger Subject: Power Can Length To: kiwi@hp850.mbari.org (William Kirkwood) Date: Tue, 30 Mar 93 16:57:40 PST Cc: meed@hp850.mbari.org (Ed Mellinger) Mailer: Elm [revision: 66.25] Status: RO Hi Bill - Concerning the power can length, I came up with a number to throw darts at for the AC side. Let me know what you think. I assumed we'd have an internal tank of about 9-10" O.D.. The transformers and inductors will be somehow secured within the tank, with 0.25" clearances between all components. The rectifier/fuse assembly will be secured to the end of the tank closest to the DC side of the can (opposite end of tank from endbell). The transformers will be 3.5" thick, the inductors 2.0" thick, and the rectifier/fuse 1.5" thick. Given those assumptions, I calculate that the length from the tank bulkhead closest to the endbell, to the top of the rectifier/fuse closest to the mid-can wall, will be 16.0 inches. That point could be adjacent to the back of the stud on the female power contacts in the wall. 16 inches is about an inch longer than the old AC side design. Notice I made no mention of the following 2 subjects: 1) vibration mounting for transformer tank. I think space can be made around the rectifier/fuse assemblies for mounting between the tank wall and the mid-can wall, however there is some other stuff (circuit board, current sensors, wires, etc) that has to go there too, so coordination will be important. 2) pump type, size, or location. I did a little looking around but haven't found anything very satisfactory. One outfit has a gear pump with DC motor that's about 2.5" dia and about 8" long, another has a centrifugal with DC motor, about 3" dia by 5" long, both WAY more pump than I think we need. (All I think we need is an aircraft-quality version of the toy pump I used for the demonstration.) An obvious spot for the pumps (both) is on the tank wall next to the endbell, I believe there is a fair amount of space there. But I think that spot would also require a self priming pump which rules out centrifugals which are otherwise ideal for our low pressure high volume (relatively) application. Let me know what you think about the length spec, and if you have any ideas on pumps. -Ed p.s. the specs I have been using for the pump are 1 liter per minute flow, 24" water head, no teflon, and 24 or 48 VDC operation (12V possible, and 400 Hz also possible.) p.p.s the world is full of nifty little DC or 400 Hz servo motors. Would the thought of building our own centrifugal pump make you gag?