Date:         Mon, 26 Aug 2002 18:58:21 -0500
Reply-To:     Larry Alofs <lalofs@ENTERACT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Larry Alofs <lalofs@ENTERACT.COM>
Subject:      Re: fuel pump power consumption?
Comments: To: jbrush@AROS.NET
Content-Type: text/plain; charset=us-ascii

John Brush wrote:
>
> Anyone have their own testing data for how much power a working fuel pump
> draws?
>
> I am getting conflicting information from manuals on the power draw for a
> fuel pump, and would like to hear what others may have tested it at.
>
> Bentley says 8 Amps, which sounds awfully high. When my pump was not
> working, it drew 8 amps, but didn't turn on or pump. It miraculously
> decided to start working today, and it draws a nice steady 3 amps.
>
> Bentley says less than 8 amps may be ground problem. That might explain
> some of my "intermittent failure to start" situations, but I would like to
> know what folks think of that 8 amp number. Just sounds high to me.
>
> Thanks much,
>
> John

These numbers sound quite reasonable, assuming the motor was physically
stuck when it was not running.  An electric motor generally draws much
more current when it is stopped or turning slowly than when it is
running at a decent speed.  The faster it turns, the more "back EMF" it
produces from the generator effect.  This voltage opposes the applied
voltage from the supply and reduces the current flow.
  Sounds like your pump was jammed up because of a mechanical problem
inside or rust, etc. from your tank.  If there was a poor ground
stopping it the current would be lower than normal, not higher like your
8 amps.

Larry A.