Toroidal Halogen Chandelier Wiring

[davidmichael]

Hi I am a DIY person and had the task of  removing the corrosion from the removable part of the light fitting (image) however I forgot to mark the wires before disconnecting them and need some help with rewiring. There is a hefty 300va toroidal transformer which is about 15 years old and has to supply 36 halogen bulbs. There are four wires coming out of the transformer forgot the colours but I think they are two blacks and two reds, blue and red  are bundled in pairs. both pairs give of 12v.

Could someone be kind enough to explain what goes where. Thanks for your help!

Oh can't post the image as I need a minimum of 10 posts. Let me contact admin see if they can make an exception.

 

[davidmichael]

Photo

 

[Sidewinder]

Can you post a picture of the other side also?

Where does the black go?

 

[ProDave]

A picture of the other side of that "plate" as well would be handy.

It looks like there's a "ring" circuit feeding those studs which will be one side of the lights? and is the other side connected to the plate?

If so it looks like there may be two transformer windings in parallel?

More pictures please.

 

[davidmichael]

Thanks for the replies! The blue ring terminals are all insulated from the metal plate. Here is an image of what it looks like assembled. I am also confused  by the single black wire.

 

[ProDave]

And a picture of the transformer bit please?

 

[pickleye]

The unlooped blue on the right looks to be connected to the plate like the black, not actually insulated from it.

 

[MajorOak]

It looks like the lights are connected in a ring with the blue as (+Ve) and the black is connected to the plate as a ground?

Looking from below the lights are strung between two metal bars, alternate bars are connected to the blue wires and the other alternate to the base.  I reckon that the blue wires connect together and the black is the return through the base.

 

[ProDave]

The complication is he mentioned 4 wires connecting to the transformer so I suspect 2 windings in parallel and that bit needs to be right.

So we await a picture of the transformer and it's connections.

 

[davidmichael]

Apologies for the delay and thank you all for chipping in. Here is the image you requested. The black and blue single wires on the detachable plate are not insulated from the plate so they are I guess both ground?

 

[ProDave]

Okay so there's two windings. they need to be connected in parallel, but the right way round.

So connect the black wire and the blue wire that are bolted to the plate to the two black wires from the transformer.

Then connect the two blue wires that form the two ends of the "ring" connecting to the insulated studs, to the two red wires.

.

 

[davidmichael]

Thank you for that advice T.  It's so logical  I must have been a twit not to think it through logically. Can you explain the reason for black and blue going to negative? Why not both wires in black?

Thanks again for the great support

 

[SPECIAL LOCATION]

Can you explain the reason for black and blue going to negative? Why not both wires in black?

Strictly speaking there is no negative...

This is just a 12v AC light fitting supplied via an isolating transformer,

where wires carry half the circuit to the lamps and the metal of the fitting carries the return.

As it looks like there is only a transformer no other rectifier circuits to provide a DC output.

then the "blues" and the "black" on the fitting are continually alternating pos'+' and neg'-' at 50hz..

So the lamp is safely isolated from the 230v mains...

and once you get inside the fitting itself there are no hard and fast rules as to what colour wires the manufacture should use

to join all his lamps back to the secondary windings of the transformer...

It may simply be that they had a few coils of wire for doing the internal lamp connections and

during manufacturing just happened to come to the end of a coil...?

or there was already an off cut of black with a crimp on it available to use..?

or someone may have taken the fitting down before and snapped a wire off so replaced it with a black?

etc..

etc..

It would only be the mains supply connection side that they must ensure correct identification..

by colour and labeling etc.. 

this bit (the 12v side) is open to the manufactures discrestion..

Guinness

 

[davidmichael]

Thank you special location for the in depth explanation. Now it all makes sense. And apologies Pro Dave for confusing your name with your Rank. I am beginning to believe that the Chinese dislike for people born in the year of the sheep due to lack of brains is turning out to be true!!! Who is qualified to help me in that dept?