How to turn on one phase while sensing three

>>934664
Correction:
More phases than ONE!

>>934664
What?
You need a current sensor on each phase. Like a clip on loop thing that goes around each wire somewhere. And a controller that operates a contactor when current is detected anywhere

Just hook it up to a light switch that also runs a ceiling fan or other dust control measures. No harm in it running a while extra. Maybe try to make one of those "cyclone" dust collector things to keep the shop vac filter clean

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>>934664
you need something like this.
http://www.amazon.com/HH52P-General-Purpose-Power-Relay/dp/B00E1L86EQ

>>934664
Nimm den Rückleiter; Der ist ja bei allen gleich, so umgehst du das Problem mit den Phasen.

Elegant wäre dann eine Strommesspule ( Linearer Stromsensor, 15 Euro), der ne Spannung induziert sobald du dein Werkzeug nutzt. Das ganze dann über einen Transistor zu einem Relais, am besten ein SolidStateRelais und voila - fertig.

> You need a current sensor on each phase

dont think so. when the motor is off, all three phases have zero current, when it's on, all three have current. so, monitoring one wire is sufficient. unfortunately, you need quite a number of turns to pick up a good-enough signal. a current clamp uses few turns but it has a laminated iron claw to amplify the magnetic field around the wire.

a better plan might be to use a hall switch to detect the motor's magnetic field, or one of those suction-cup telephone recorder magnetic pickups. another option is an IR proximity detector pointed at some moving part, like the shaft, painted with a stripe, or the motor's fan blades.

>>934741
sry.

Take the neutral / return conductor; so you don`t have to worry about the phases.

Best idea would it be to use a coil for inducting a few Volts. Thenuse a transistor to run a Relais. (SSR)

>>934664
Use three of these guys ( https://www.sparkfun.com/products/11005 ) plus a microcontroller.

Buy them from somewhere else that's not sparkfun.

Don't bother with being too clever, just calculate the total current draw, then subtract what you've measured the dust extractor to use if it's switched on. You certainly could make it work like in OP, but then you'd have to change the code whenever you got another tool.

Obviously you'll want to be using an optoisolated relay; buy that as a board unless you're confident mixing your own home-designed and built electronics with mains electricity.

>>934749
>Take the neutral / return conductor; so you don`t have to worry about the phases.
I thought three-phase devices didn't necessarily use the return conductor?

>>934727
I do indeed have a cyclonic sucker. It started out as a vacuum cleaner with a plastic can. Now it is a steel behemoth that can turn on a LADA by sucking from the tailpipe. Noisy but highly effective.

>>934741
Ich sprechen nicht Deutsch. Alles meine deutch ist:
Habst du lust? Nein, ich have Kopfsmertchen.

This linear current sensor needs to be investigated if it is a thing.

>>934754
You are correct. Phase-to-phase. Then you get the extra oomph provided by 400V. Without the 3~ this would be much easier...

>>934753
This seems promising. I'd like to avoid microcontrollers if it's possible as I know nothing of them. I'm more of a weld it screw it nail it drill it of a type. But if it's unavoidable...

Maybe you are talking about the same as >>934741

>>934747
if you read the op you would know there is a mix of 3 phase and single phase.

>>934749
not for 3 phase necessarily.

>>934763
its not impossible, you could probably do something with linking a few control modules together but getting it to ignore the extractor might be difficult unless its on its own phase.

microphone to detect loud white noise of powertools to turn on the vac?

There exists a product that is a hose gate that whenever you open the gate, your dust collection comes on. So ideally you'd have every gate closed then open the gate at the machine you're working at, then only 1 gate is open and you're maximizing your suction. TheSamuraiCarpenter installed them in his new workshop, he mentioned it in a recent vid I think. Can't remember the name of the product though

>>934664
Drew you a picture of what I think you're looking for. I would need to know how much current all your tools draw to size the relays/resistors/CT's but it's easy math.

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>>934808

>>934763
Microcontrollers are the lego of computers.

If you can explain what you want done to an complete idiot with no common sense whatsoever, who will nevertheless do exactly what you say in the exact way you said it, you can program a microcontroller.

For just about any application, someone will have made a prefabricated board that you just plug into an Arduino, so you don't need to do any electronics unless you want to.

>>934813
>>934808
Won't that latch on, as the extractor relay will get actuated by the extractor motor's current draw?

>>934826
>latch on

Was thinking the same.

Question for OP: Are all the single phase devices on the same phase?

>>934829
>>934826
Good call. You can use a differential CT circuit. To eliminate the latching problem. Or just use an Arduino as other people have pointed out. Might be easier. I dunno, I do protection relays, not programming.

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>>934850
One of these days I'll remember to attach the picture with the post.

Rotary phase converter and a current sensor solenoid switch?

Simply buy a DIN current monitoring relay and a contactor and your done. If you want to get tricky the contacts in the current relay might ok for direct control of the extractor.

OP here! Thanks for all the good ideas! I'll review this idea and see if I can make it all automate!