# Help designing an iVac switch



## joecaption (Nov 30, 2011)

Single or 3 phase?


----------



## FrodoOne (Mar 4, 2016)

alejandro.mc said:


> I'm trying to design an ivac switch box. The basic function of this box is to plug your tool (circular saw, dropsaw, etc..) to the box, plug your vacuum cleaner to the box, and plug the box to the power source, 220v in my case since I live in New Zealand. The idea behind the device is that when you trigger the tool and start cutting, the vacuum is turned on at the same time, for the duration of the cutting + 5 seconds. Obviously to suck the dust that's otherwise harmful.
> 
> So this item is already being produced in USA. The problems are:
> 
> ...


What you are seeking is the function performed by a "Master/Slave" power board, but with the "Slave" output continuing for 5 seconds after the "Master" has ceased to draw current.
Master/Slave power boards are designed to turn on peripheral equipment associated with Computers and TVs etc. but I have not noticed that any have the extension on the "Slave" output that you require.

However, if you search on "Master slave switch circuit" you may fine one or two which could be adapted for your purpose.
e.g. http://www.eeweb.com/blog/extreme_circuits/masterslave-switch
(increasing the value of C2 may cause the "Solid State Relay" to maintain conduction for longer but for what you require, some redisign is probably required to increase the available voltage across D1 - D3 (more diodes or a Zener diode) a larger capacitor for C2 and a limiting resistor in series with the LED in the Solid State Relay.)

http://sound.westhost.com/project79.htm
(This has the disadvantage of requiring a separate 12 V supply and I have not given the circuit much thought.)

http://downloads.deusm.com/designnews/Description_and_Build_Instructions.pdf
http://elektrotanya.com/files/forum/2012/06/e98bX14.pdf
http://www.aaroncake.net/circuits/loadswitch.asp
(The above 3 are presumably US, therefore, designed for 120 V and probably require some modification.)

http://www.renovateforum.com/f195/wiring-master-slave-switch-workshop-dust-extraction-94912/
This is 2010 thread on an Australian site which may be more useful to you.
(I suggest that you are likely to get advice more "appropriate" to New Zealand practices and availability of items from an Australian site.)


----------



## FrodoOne (Mar 4, 2016)

*Master/Slave Switch*

See also https://www.kemo-electronic.de/en/T...3N-Master-Slave-switch-230-V-AC-400-V-AC-.php


----------



## FrodoOne (Mar 4, 2016)

alejandro.mc said:


> I'm trying to design an ivac switch box. The basic function of this box is to plug your tool (circular saw, dropsaw, etc..) to the box, plug your vacuum cleaner to the box, and plug the box to the power source, 220v in my case since I live in New Zealand.


Alec,

I have some further thoughts concerning a design for the IVac switch (with delay) which you require.

It would be of assistance if you could advise the running current (or wattage) of each of the tools (circular saw, drop saw etc.) and the vacuum motor.

Regards


----------



## Bob Sanders (Nov 10, 2013)

You need a current switch. A coil sensor is placed around the tool wire and senses when a tool is being used. You can get one for around 20 bucks:










http://www.ebay.ca/itm/AC-Current-S...968363?hash=item3ab30b586b:g:utMAAOSw42JWD6KO

If you wish to add delay to it then use a timer. I like the ones below:

http://www.ebay.ca/itm/DC-12V-Multi...Time-Switch-/271958222133?hash=item3f51f92535


----------



## FrodoOne (Mar 4, 2016)

Bob Sanders said:


> You need a current switch. A coil sensor is placed around the tool wire and senses when a tool is being used. You can get one for around 20 bucks:
> 
> http://www.ebay.ca/itm/AC-Current-S...968363?hash=item3ab30b586b:g:utMAAOSw42JWD6KO
> 
> ...


The unit suggested by Bob Sanders seems to be an interesting idea.

However, to be usable safely, it would need to be mounted inside a suitable "Box", with an input lead and "Master" and "Slave" Socket Outlets.
(While these would probably cost more than the unit itself, this often applies to simple electronic projects.)

Unfortunately, when completed, the "set-up" would then only provide virtually the same facilities as a "Master/Slave power board" (power strip) - which can be easily obtained, starting at about $30. (Note that, in Australia and NZ) these are all rated at 10 A total loading and include a "circuit breaker" which operates if this current is exceeded.)

(Also, to achieve the 5 second "extension" of the "Slave" operation which you desire would require quite a few modifications other than "just use a timer"
While the one suggested could switch 230 V AC, it has 12 V input (the other device has a switch-mode power supply with 24 V output) and it is not clear how it would be triggered to extend the "Slave" output.)


I checked one Master/Slave power board which we have in use and found that the "Slave" output remained "active" for about 2 seconds after the "Master" (TV) was turned off. It may be possible to extend this delay and I will try to investigate this at some time in the next week.

As previously requested, your advice as to the running current (or wattage) of each of the tools (circular saw, drop saw etc.) and the vacuum motor would be appreciated.


----------



## Bob Sanders (Nov 10, 2013)

FrodoOne said:


> (Also, to achieve the 5 second "extension" of the "Slave" operation which you desire would require quite a few modifications other than "just use a timer"
> While the one suggested could switch 230 V AC, it has 12 V input (the other device has a switch-mode power supply with 24 V output) and it is not clear how it would be triggered to extend the "Slave" output.)


The current switch and timer I posted are simply examples They come in all different voltages and amperages.

http://www.ebay.ca/sch/i.html?_from...rent+switch.TRS1&_nkw=current+switch&_sacat=0

http://www.ebay.ca/sch/i.html?_from...Xtimer+module.TRS0&_nkw=timer+module&_sacat=0

As for adding a timer I'm not sure why you think it to be a complicated venture. It is not at all. This project would take maybe an evening to complete.

These timers BTW are extremely versatile little devices and can be rigged for just about any timing or delay project. Here's a youtube on them. The one depicted is the older version... but they are the same. The newer ones are simply easier to program:


----------



## alejandro.mc (Mar 11, 2016)

p { margin-bottom: 0.25cm; line-height: 120%; } Hi everyone, I just wrote a massive reply and when I put submit reply the forum sent a message 'you need at least 1 post to post a link' and I lost the whole post I typed.. so I'll try to summarize:

Thanks to everyone for replying with so many ideas and so soon! Great forum!!

Info on the tools:

vacuum: 1000 W

circular saw: 1600 W




If I get this right I'm in need of the following:

1. Box

2. Wires

3. Switch 

4. Timer 

5. Sockets to install in the box, to plug the vacuum and the tool

6. Maybe a Switch On/Off to cut all the power in the box..

Would I be missing something?

Question how would I wire all this together? ; ) I'm talking to my sparky friend tomorrow, see if he can translate a couple of this things for me heheeheh.. I'm just a humble carpenter : )

Will post feedback and will keep you updated. Please carry on posting ideas or tips on how to build this! 

I'm very grateful to all for the help so far and the help that might still arrive!

Cheers,

Alec


----------



## FrodoOne (Mar 4, 2016)

alejandro.mc said:


> Info on the tools:
> 
> vacuum: 1000 W
> 
> circular saw: 1600 W


Here we may have a small problem - if you intend to run this device from a "Standard" NZ/Australian 10 A Socket Outlet.
The nominal total "Running" Wattage is 2600 W which (at 240 V) is 10.8 A

Also, with both devices starting at the same time, the start-up surge current may trip the 16 A circuit breaker with which a (group of) 10 A socket outlets are supplied.
(Check with your "sparky friend" about slow acting circuit breakers which are designed for this situation.)
Because of ths "start-up current, it may be wise to add a "delay" to the start-up of the "Vacuum" circuit as well as having it run for about 5 seconds after the saw is switched off. (I do have some ideas concerning both of these items.)

While, in practice, the 10 A socket outlet supplied by the 16 A circuit breaker would (probably) work, this current does exceed what MAY be "drawn" from such a 10 A socket outlet.

"Officially" (according to regulations) such a device should be supplied from either
A 15 A socket outlet or
Two 10 A socket outlets - one for the "Master" supply (Saw) and "one for the "Slave" (Vacuum). (i.e. Two leads connected to a double socket outlet.)

This also precludes using a modified Master/Slave power-board, since these are fitted with 10 A circuit breakers (cut-outs)

Again I would point out that, while some interesting posts have been made on this North American site, others there may not have been able to advise you of these points - although I am sure that your "sparky friend" would have pointed this out - and I again recommend the Australian site http://www.renovateforum.com/forum.php 
(You could post on both - and get the best [or worse] of both worlds.)


----------



## FrodoOne (Mar 4, 2016)

alejandro.mc said:


> p { margin-bottom: 0.25cm; line-height: 120%; } Hi everyone, I just wrote a massive reply and when I put submit reply the forum sent a message 'you need at least 1 post to post a link' and I lost the whole post I typed.. so I'll try to summarize:
> 
> Thanks to everyone for replying with so many ideas and so soon! Great forum!!
> 
> ...


Further to my previous post, I may have given more emphasis than was necessary to the peak current drawn and how it may affect the circuit breaker concerned.
Obviously, assuming that they are now both fed from the same circuit breaker, if you can now turn on the Saw and the Vacuum at (virtually) the same time without tripping the circuit breaker there is no problem.

Assuming that you use the "Current Sensor Module" referenced by Bob Sanders, your basic "component" costs (in AUD) would be as follows: -

Box 11.79
Current Sensor Module	23.73
Socket Outlets 20.00
Cable 9.00 - 3 metres, including internal "Box" wiring.
Cable Gland 6.50 - this is necessary to secure the supply cable.
Plug 4.50
Total 75.52
(Surprising, is it not?)

Added to this, I know that I can design an "outboard" circuit to provide a range of start-up and shut down delays for the "Slave" circuit for between $10 to $15 in the cost of the required "components".


----------



## alejandro.mc (Mar 11, 2016)

Hi Pete, I have no words mate. Thanks for the help, I still haven't talked to my friend, which by now I definitely NEED. Because half of what's written here confuses me deeply. Way over my head. BUT, I am very happy you found my project interesting, and that you have decided to make it happen too!

Thanks for the quote too, I'll start putting some money together, because that's going to be like 100 NZD..

Since you are spending the time on it, and without any sort of commitment, or time limitations, because this is a long term project for me, not in a hurry, if you'd like to make like a diagram of this, it might be more effective for my simple mind ; )

Thank you again for the help. I haven't answered private messages because I haven;t reached the amount of post yet : ( Soon!

Cheers mate, I'll write a bit more once I see my mate and have him translate a bit of what's going on here!

Cheers mate,

Alec


----------



## FrodoOne (Mar 4, 2016)

Alec,

Thank you for your response.

Your "project" interested me from the start and I was particularly interested when Bob Sanders brought to our attention the AC Current sensor (http://www.ebay.ca/itm/AC-Current-Se...MAAOSw42JWD6KO)

If you look at the picture(s) on that site, you will see that there are two transistors adjacent to the Relay (SRD-24VDC-SL-C) and it is certain that one of these is "driving" the relay when it is "energized" by the circuitry to the right of the relay.
My thought is to "remove" that transistor (to an outboard circuit), connect that outboard circuit to the circuit board terminals where the transistor was located (plus, connect to the 24 V supply on the circuit board) and build the required extension time - and possibly a start up delay - on that outboard circuit.

I have designed the required circuit in my head and am half-way towards getting it down on paper (actually, in a circuit drawing program which I use.)

Both the Sensor and the Box have been ordered, as these are the only items that I can't source here - certainly not at the prices mentioned. However, I expect about a two week delay in receiving them.
When I do receive the sensor, I will confirm that I am on the right track before finalizing the design.

By the way, what was the cost of the commercial item to which you referred in your first post. I did locate it but could not see any quoted price.

Cheers.


----------



## alejandro.mc (Mar 11, 2016)

It's around 110 NZD from e-bay in the New Hampshire, USA. But the problem is that it is 110v.

From Amazon UK I believe you can buy just a switch, at an unreasonable price.

Those are the ones I found.

Cheers mate,

Alec


----------

