Need fan to come on when Comp fires...??

I need a fan/blower to come on when the compressor fires. The compressor is in a sound-reducing box & needs to be force vented.
All I really need is to understand how this would be achieved. I don't want to play wif the zappy bits myself. rather have someone (a sparky?) make/install something for me.
I just want to understand what's required & how it works so I don't get ripped off. We've had 2 sparkies try it on in the last 12 months. :oo:

Any help would be appreciated.

This was discussed in this thread:

http://www.woodworkforums.ubeaut.com...ing#post440708

but for dust extractors, same principle though.

I have seen several articles in the American woodworking magazines that use these current sensing devices.

Quote:

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Originally Posted by Big Shed

This was discussed in this thread:

http://www.woodworkforums.ubeaut.com...ing#post440708

but for dust extractors, same principle though.

I have seen several articles in the American woodworking magazines that use these current sensing devices.

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I had a look (at the thread) but I don't see what will help me understand what's required. A relay or current sensing thingy?
The current sensing thing appeares to be for a small DC (less than 2000CFM) not a large 240V comp which would draw more power.

It is not the amount of power that gets the thing to switch on, it is the current flow.

In the case of the DC, when the saw, router or whatever, is switched on the device senses there is current flowing through that circuit and switches on the DC. When the saw etc is switched off, the current stops flowing and the DC is switched off.

I will try and find the article tomorrow.

There are all sorts of complicated ways to do this.
& yep I do have a very funky box to do it (still not to market)

But for a compressor a connection to the switched side of the preasure switch would be just fine.
so the fan runs when the motor does.

Easily done.
Can do that one for you.

cheers

Quote:

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Originally Posted by soundman

There are all sorts of complicated ways to do this.
& yep I do have a very funky box to do it (still not to market)

But for a compressor a connection to the switched side of the preasure switch would be just fine.
so the fan runs when the motor does.

Easily done.
Can do that one for you.

cheers

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Soundman,

You, my friend, have a sale!!
for cash-folding-money even! :U :U :U

soundman got it right, its the siple and relatively easy way to do it