[Sussex] Outcome Re: OT: another hardware question

[Antony]

On Mon, 08 Jun 2009 15:35:08 +0100 Jacqui Caren wrote:
> Antony wrote:
> > Where can I find a circuit (or buy a gadget) to slow-start DIY tools
> > e.g. circular saw up to 1200W?  I've Googled MAO in forums etc. without
> > success.
> 
> Hmm I would pop into the farnborough maplins, Ask for Jim
....<refs snipped>...
> I would expect the whole shebang to be a single IC these days.

Thanks Jacqui for the interesting leads.  The quick summary is that
there seems to be a market opportunity here [0]   :-(   There are cheap
DIY tools with built in soft start [1], but in standalone "soft
starters" [2] I only found 3 phase, mostly for large industrial motors.

The circuits you found got me wondering: could a simple triac controller
like [3] be run in DC mode as in [4] circuit 1c, and fitted with an RC
on the gate so as to ramp up when power is applied?  It's beyond my
skills though - any offers?

Antony

[0]  http://www.diynot.com/forums/viewtopic.php?t=98635  (search for
"surprised")
[1]  eBay.co.uk item 400054540068
[2] 
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0325457
[3]  http://www.quasarelectronics.com/kit-files/electronic-kit/3019.pdf
[4]  http://www.st.com/stonline/products/literature/an/2477.htm