Modify smart power strip to turn on separate 110v circuit?

[BadMouth]

Anyone here tear apart and mess with a smart power strip?

I'm looking at devices to automatically turn on the dust collector in my workshop.
They are around $50.

That's not bad, but I've got some extra smart power strips laying around and I wonder if those could accomplish the same thing without much hassle.
The trick here is that the dust collector needs to be on a different circuit than the device triggering it.

So, anyone ever tear one down and fiddle with it?

[Mike A]

Don't plug your dust collector into a power strip. Double don't plug your dust collector into a power strip that you tinkered with.

[Mike A]

Sorry. That wasn't very helpful. Your dust collector will either bog down or just trip the fuse on the smart strip. If it starts bogging down everything starts heating up.

[pbj]

Do you just need an outlet timer, or is something else going to trigger the dust collector?



It's pretty easy to modify a cheap power strip with a microrelay.....

[BadMouth]

Do you just need an outlet timer, or is something else going to trigger the dust collector?



It's pretty easy to modify a cheap power strip with a microrelay.....

I want the dust collector to turn on whenever a tool that is connected to it is turned on (table saw, band saw, jointer, etc)
Available devices for this pupose run for 7 seconds after the tool is turned off, but my smart strips stay on for about that long too.



Mike A,

The dust collector is only on a 15 amp circuit and doesn't trip that.  I'll see if the smart strip has any specs listed on the box.
It's probably a fairly cheap one.  I got two free from the electric company as a renter, then after buying the place and switching the service to my name they sent two more.

[DaOld Man]

I wonder if you could use a current loop (coil of wire wrapped around the wires going to your tools), to trigger the dust collector?
The loop would pick up current when the tool was running, and that current (voltage coming out of the coil) could trigger a time delay relay which would turn on the dust fan.
When the tool turned off, the timer would time out and turn off the dust collector.
You could experiment by wrapping some wire (16 GAUGE MAYBE) around one of the conductors going to the tool (dont wrap it around both, cause that would cancel the induced voltage on the coil), then measure the voltage on the coil while the tool is running. You could then calculate that voltage to turn on a transistor that would turn on a relay that would turn on the dust fan.
Of course the voltage from the coil would be AC, so you will have to rectify it (diodes). And you could use a capacitor to keep the transistor turned on for a while after the voltage from the coil goes to zero (current on tool goes to zero, which means the tool is turned off).
You could use multiple coils and transistors to turn on the dust fan for each of your tools, or position the one coil on the main for all your tools, so any of them will trigger the circuit.
Just a little food for thought. Keep us posted on your progress.

[DaOld Man]

Here is a link to a site discussing basically the same thing you want to do, but instead of lighting an led you would be firing a transistor. (excellent application for a opto-isolator)

http://www.electro-tech-online.com/threads/current-sensing-circuit-idea-for-240v-ac.119408/