DOL Starter / automatic dust extraction system

Stormtroeper · Jul 31, 2019

Could I use a DOL Starter circuit to create an automatic extraction system? I was thinking that I could replace the start button and simply wire in a socket instead. So hypothetically if I plugged in and switched on an electric palm sander, it would start up my dust extraction systems (via the contactor) automatically.
Thoughts?

SheffSimon · Aug 23, 2019

Stormtroeper said:
Could I use a DOL Starter circuit to create an automatic extraction system? I was thinking that I could replace the start button and simply wire in a socket instead. So hypothetically if I plugged in and switched on an electric palm sander, it would start up my dust extraction systems (via the contactor) automatically.
Thoughts?

I made something similar for my brother. Used a thing which fitted around a chop saw motor live conductor, bit like a current transformer but just provided a contact which then pulled in a contactor to energise a socket which powered a dust extractor. Also had a run on timer to keep the extractor going for a while, helps prevent intermittent stop starts and also gave better dust extraction.

I'll try to find the RS part number and post it here.

Simon47 · Aug 23, 2019

You need a load sensitive switch - basically a current driven relay rather than voltage. You arrange for loads that need dust extraction to run through the switch, switch detects the load current & operates the DOL starter. The starter needs to be wired for external control rather than latching on the push buttons (or get one without buttons), and as suggested it would be a good idea to have a run-on timer.
Rather than buy a cased starter, might be better to get a DIN rail enclosure and mount the contactor, timer relay, and current relay in the one box. I'd be inclined to put the case on a board with a mains cord (or power inlet) and 2 separate sockets - one for the extractor unit, the other for the load.
As an idea of what's available, see this selection at RS
You need to look at minimum current sense, maximum current capacity, supply voltage, and switching type/capacity. Some put the sensed current through the device, others have a CT (current transformer) sticking out the front that you feed the load supply (only one) wire through.

EDIT: TBH, I suspect that by the time you've priced it all up, you'll decide it's not worth the expense to avoid having to flick a switch

netblindpaul · Aug 23, 2019

Plus the legislation if it's not for DIY at home, and, even then it's possibly an issue.

static zap · Aug 24, 2019

Have pondered a sound triggered version.
No connections required ...
(bar turning it off at the end of the Job--If it hears its own noise..!)
Do like idea it waits for other device to get up to
speed -before springing into life.
(A Delay would be missing feature -of prev.
mentioned -wired design)
(as causing -2 devices to turn on-in unison is a negative = supply glitch)
--Inventions -a variant of "Clapomatic-light"--
(all sorts of dodgy designs to follow)