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From: Thomas Langaas on 15 Feb 2010 10:47
Hi!

I was wondering if anyone could give me a few hints / pointers on
building blocks in the following design / idea:

I have a few powertools that generate dust; circular saw, sanding
machine, etc. And, I have a dust extractor / vacuum cleaner. My idea
was that instead of hearing the constant buzz from the dust extractor,
it could turn on and off depending on the state of the power tools; eg.
the current drawn through the outlet they're connected too. A nice
feature (but I guess would at require microcontroller for sure) would be
to make the power used by the vacuum cleaner variable based upon how
much current is drawn from the outlet.

My first step would be to create something that turns on/off when the
current passes a defined threshold (on if it's above, and off it's
below).

In advance, thanks!


--
Thomas
From: keithw86 on 15 Feb 2010 11:01
On Feb 15, 9:47 am, Thomas Langaas <thomas.lang...(a)gmail.com> wrote:
> Hi!
>
> I was wondering if anyone could give me a few hints / pointers on
> building blocks in the following design / idea:
>
> I have a few powertools that generate dust; circular saw, sanding
> machine, etc.  And, I have a dust extractor / vacuum cleaner.  My idea
> was that instead of hearing the constant buzz from the dust extractor,
> it could turn on and off depending on the state of the power tools; eg.
> the current drawn through the outlet they're connected too.  A nice
> feature (but I guess would at require microcontroller for sure) would be
> to make the power used by the vacuum cleaner variable based upon how
> much current is drawn from the outlet.
>
> My first step would be to create something that turns on/off when the
> current passes a defined threshold (on if it's above, and off it's
> below).
>
> In advance, thanks!

I use one of these on my SCMS and shop vac:

http://www.woodcraft.com/Product/2005855/18215/I-Socket-Vacuum-Automator.aspx

I douldn't want my dust collector cycling that often so use a remote
control for it:

http://www.pennstateind.com/store/LR220-3.html


From: Ecnerwal on 15 Feb 2010 11:06
In article <slrnhnir3l.b4s.tlan(a)firefly.xen.no>,
Thomas Langaas <thomas.langaas(a)gmail.com> wrote:

> I was wondering if anyone could give me a few hints / pointers on
> building blocks in the following design / idea:
>
> I have a few powertools that generate dust; circular saw, sanding
> machine, etc. And, I have a dust extractor / vacuum cleaner. My idea
> was that instead of hearing the constant buzz from the dust extractor,
> it could turn on and off depending on the state of the power tools; eg.
> the current drawn through the outlet they're connected too. A nice
> feature (but I guess would at require microcontroller for sure) would be
> to make the power used by the vacuum cleaner variable based upon how
> much current is drawn from the outlet.
>
> My first step would be to create something that turns on/off when the
> current passes a defined threshold (on if it's above, and off it's
> below).

Your second part is not practical with a typical single-phase induction
motor. If your dust collector is three-phase unit, it's possible, though
it may not be desirable - slowing a dust collector down can result in
dust dropping out in the lines - the system should be designed to
maintain a particular velocity inthe collection liones, and slowing it
down will mess with that.

The second part is available off the shelf as a commercial product. An
easier (and cheaper) solution is to put switches on the blast gates (you
do have blast gates, one hopes) and connect them to a relay that turns
on the dust collector.

--
Cats, coffee, chocolate...vices to live by
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