Re: (ET) Vacuum running, man does it draw power.

[David Tiefenbrunn <davidtief comcast net>]

Most blowers and pumps actually draw less power under deadhead conditions.  Full open ports / no back pressure or no vacuum to pull against is the maximum load.  It has something to do with the aerodynamics and stalling of the "wings".  I don't remember the technical details.

Dave


On 10/30/2019 11:58 AM, Charlie wrote:

Chris, are you still heavily restricting the output air flow?  Maybe that would explain your crazy current draw.  I run the noggler for a couple of hours with a stock lead acid battery pack, but I have a 5'x3' panel of 1/4" steel hardware cloth letting the air out of the top of the leaf collection cart.

Apologies for not sending the pictures yet!

--Charlie

On Mon, Oct 28, 2019 at 8:35 PM Rob Brockway via Elec-trak <elec-trak cosmos phy tufts edu> wrote:

I have an elec-trak vacuum blower I bought new from Bill Gunn years ago.  Mine does not draw a lot of amps, perhaps 15-22 amps.  I can check the actual amount next weekend if you would like.  Reduces my range a  notably but nothing dramatic.

On Monday, October 28, 2019, 11:41:47 AM EDT, Ken Olum <kdo cosmos phy tufts edu> wrote:

  From: "David Roden" <etpost drmm net>
  Date: Sun, 27 Oct 2019 20:41:43 -0400

  If you're running a 90ah battery flat in 30 mins, your load is 180 amps! 
  That's HUGE.  Lead batteries do NOT like that kind of load.

A similar problem with snow blowing is why I have AGM batteries in my
Ox.  But there are some other issues.  Is an Elec-Trak wired with AWG 6
wire?  I don't remember.  AWG 6 is rated for 75A (with 90C insulation
and 20C ambient).  And isn't there a 90A circuit breaker?  Leaf
vacuuming is much more of a continuous activity than snowblowing and you
do it at higher outside temperatures, so overheating seems like an issue.

                                        Ken

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