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Topic Title: Contactor
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Created On: 08 December 2012 10:49 PM
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 08 December 2012 10:49 PM
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Westonelectrical

Posts: 85
Joined: 26 November 2012

Can someone tell in (simple terms) how a contactor works and why you would use it?
 08 December 2012 10:52 PM
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DOUGIE1000

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Switch wire to coil to switch on larger loads ie motors

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 08 December 2012 10:56 PM
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Westonelectrical

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Just wondering how it would work on a lighting circuit
 08 December 2012 11:13 PM
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DOUGIE1000

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A good example is a job we did few weeks ago, rows of contractors all in a lockable box, one 1.5mm ran to one light switch at this shop front door, the one switch put supply onto all the contractors coils and brought them on switching on all the lighting circuits for the store lighting.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 08 December 2012 11:43 PM
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Westonelectrical

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What was so beneficial about it?.
 08 December 2012 11:46 PM
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DOUGIE1000

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Switching higher amp loads, or several contacts at once

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Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 09 December 2012 12:09 AM
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hifly

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it's a relay like you have on your starter motor in a car or van.

it alows you to switch a high load (lots of amps) with a normal switch (few amps)

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Vince

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 09 December 2012 04:07 AM
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Martynduerden

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I often use them to control full DB's essentially it provides the ability to switch on a large 3 ph board or a series of them with a light switch.

Tesco stores for example can be shut down with two key switches deepening on the requirement all done via several contractors.

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Martyn.

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 09 December 2012 04:31 AM
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ebee

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Another example is using a single phase circuit to control a 3 phase circuit.

Or an extra low voltage circuit to control a low voltage circuit.

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Ebee (M I S P N)

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 09 December 2012 08:24 AM
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Rulland

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I'd sometimes like to lock fellow contractors in a box too Dougie!.

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 09 December 2012 10:07 AM
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Westonelectrical

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For example? A photo cell will switch the contactor on to allow the power to the light??. Is that right?
 09 December 2012 11:47 AM
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impvan

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Think of it as an 'electric crowbar'. You can switch a lot of power with a very small signal.
 09 December 2012 12:06 PM
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DOUGIE1000

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Originally posted by: Rulland

I'd sometimes like to lock fellow contractors in a box too Dougie!.


For once the spell check was spot on

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Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 09 December 2012 12:23 PM
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DOUGIE1000

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Originally posted by: Westonelectrical

For example? A photo cell will switch the contactor on to allow the power to the light??. Is that right?


Spot on, photocell to switch on large lighting loads.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 09 December 2012 12:42 PM
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Westonelectrical

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Nice one could it switch for not so large lighting load
 09 December 2012 12:46 PM
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Legh

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I have used them in conjunction with remote wireless key fobs. You lay in bed and with the press of a button all your garden lights come on. Press another button and your lake fountains and water features spring to life.

The wireless HF switch is connected to a control box which then activates the coil circuit of your contactor/s which then energizes lighting, power, pumps, DBs. The HF remote input has relatively little current passing through the system which is used to switch on heavy loads or just about anything you like.

Legh

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 09 December 2012 02:02 PM
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DOUGIE1000

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West one,

Contractors come as small as 16amp 100amp, they even come mcb size and are great

We recently wired a house and had a contractor for all lighting and ring mains as woman was afraid of leaving the oven on or something when leaving.
We had a delegate board for radials for smokies, fridge freezer etc.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 09 December 2012 02:07 PM
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daveparry1

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Still calling them contractors then Dougie!

Dave.
 09 December 2012 02:24 PM
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Legh

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Yep, go into any hotel room operated by a card security system and plug in your card....and the power comes on..

Legh

-------------------------
Why do we need Vernier Calipers when we have container ships?

http://www.leghrichardson.co.uk

"Science has overcome time and space. Well, Harvey has overcome not only time and space - but any objections."
 09 December 2012 02:30 PM
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DOUGIE1000

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Originally posted by: daveparry1

Still calling them contractors then Dougie!



Dave.


Its this tablet, haha

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
IET » Wiring and the regulations » Contactor

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