Contactors : and how they work

[LukeScotty]

righty, could we possibly explain how to wire this up, bare with me please cus I don't do this everyday, lets imagine that I'm doing one next week (most unlikely) anyways

this is the contactor http://www.mkelectric.co.uk/images/products/6420S.JPG

lets pretend we've got 2 circuits, one for the contactor and one for alot of high powered lights

am guessing A1 and A2 energise the coil ? so.... line to a1, neutral to a2 ?

whats next, and wiring the lights to - from and via the contactor

regards

 

[MacSparky]

Nice cant wait for the explanation on that one.............lol

 

[wayne]

oh f**k here we go
two circuits one to energise the coil one to power the lights
1st circuit ,wire from your mcb(control circuit ) to your light switch (normal everyday thing)then back to your a1 terminal .neutral of this circuit is taken straight to the a2 terminal
2nd circuit (power circuit ) is taken through the terminals of the contactor (l1,l2,l3...t1,t2,t3)and back out to your lights .neutral is taken straight to the lights
dont forget the relevant earths and make sure the contactor is correctly sized ,also check the control voltage info
this is the most simple way of doing things it gets fun when you add pir sensors ,timers photocells................
have i missed anything?

 

[LukeScotty]

how is the neutral jointed through, connector block (through crimp?) within the contactor? if ran in armoured cable??

cheers wayne,

 

[wayne]

a contactor is a self contained item , if you are talking about the enclosure then lets continue
you have two circuits ,that is two feeds two neutrals two earths
if you are junctioning the neutral through the enclosure via a teminal block or crimp,for the power circuit either is fine i prefer terminal block

 

[LukeScotty]

is joining the neutral via the contactor acceptable? like a double pole one or something?

 

[Shakey]

Yes Luke, this is done as well.

I have used large contactors where there are fixed terminals for the neutral in and out, or an additional set of contacts for the neutral

The contactor you have shown is 3 pole, so could be used for three phase (L1, L2 and L3)
or single phase using two of the three contacts to switch line and neutral


- i dont know if you are aware, but a lot of industrial three phase systems (particularly those supplying motors) dont use the neutral anyway!

 

[wayne]

indeed thats why you can find contactors with 400v coils

 

[LukeScotty]

what about contactors with a2 at the top and a2 at the bottom of the contactor, are they linked in some way, so it doesn't matter which one you put the neutral in??

 

[wayne]

correct, put a ohmeter on them to see

 

[rumrunner]

Goodmorning all,
Try this link,Welcome to www.wiringmanual.com
Have a nice day

i forgot to say theres a button at top of page for pdf download

 

[MacSparky]

Nice find rumrunner

 

[wayne]

excellent find thank you

 

[LukeScotty]

spot on cheers,