Re: Central Vac overload

["Robert Green" <robert_green1963@xxxxxxxxx>]

"jamesgangnc" <jamesgangnc@xxxxxxxxx> wrote in message
news:b4f81cd1-dad7-4e35-85a3-3f5a99ce0cb4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Mar 31, 10:49 pm, "Robert Green" <robert_green1...@xxxxxxxxx>
wrote:
> "John Gilmer" <jlgil...@xxxxxxxxxxxx> wrote in message
> > > I am going to try a test today with my Kill-0-Watt meter
>
> Blocked and whining 8.83A, Unblocked free running inlet port - no house
> piping attached (cleanout, open actually) 12.96A
>
> External air output pipe ran free when unblocked but dropped to very low
> flow when the hose was blocked. If there's an internal check valve, it's
> venting to someplace other than the vacuum's output pipe.
>
> I used a compresible coil type cheap plastic hose in the basement, and
when
> blocked at the nozzle it contracted considerably indicating that there was
> still a serious vacuum being maintained.
>
> Another theory. It takes more work to create a vacuum than maintain it, so
> when the hose has contracted as much as it can, the motor has less load on
> it and thus the current drops. With an open vacuum, the motor is
constantly
> sucking and never achieving even a partial vacuum within the tubing.
>
> C'mon. There are smart people here.
>
> Why would a plugged vacuum cleaner draw less current?
>
> --
> Bobby G.

<Somebody else answered that once already.  Basically it's not moving a
bunch of air so it's not "working" any more.  Now that you know the
current you should able to design a circuit that alarms at the 8 amp
range and is off at the 12 amp range.  A 1/4ohm power resistor will
give you about a 1 volt variation between the two.>

Unfortunately my server delivers posts in frighteningly non-chrono order and
I reply the same way. I *do* get it now and realize why my portable
submersible pump makes the same kind of increased noise when it starts
running dry.  It takes a lot less power to raise air ten feet than water.

Live and learn . . . eventually.  Then go senile and repeat.

--
Bobby G.