# Toroidal transformer for 12V track lighting?

#### bernardgreen

I think you can connect dissimilar transformers in series or parallel for current sharing or voltage increasing with some cases requiring resistors to alter the current sharing.
It is possible to connect dis-similar secondaries in series to increase voltage provided the inter-winding break down voltage is not exceeded.

Connecting dis-similarsecondaries in parallel is not a simple matter.

the 7.5 units will soon short and you're back to 30 kV.
Almost certainly insulation breakdown as the 7.5 kV secondaries will be 30 kV and 37.5 Kv above their primaries when feeding a steady load. Using them to create arcs will create many tens if not hundreds of kV back EMFs when the arc breaks.

#### JohnW2

It is possible to connect dis-similar secondaries in series to increase voltage provided the inter-winding break down voltage is not exceeded. Connecting dis-similarsecondaries in parallel is not a simple matter.
Indeed, very far from simple, and something that would normally only be done in exceptional circumstances, and by people who fully understood what they were doing.

Porque, please bear in mind that this is a DIY Electrics forum. That being the case, I would suggest that even hinting at the possibility of connecting dissimilar transformer windings in parallel is very inappropriate, and arguably irresponsible.

Kind Regards, John

#### ericmark

It is possible to connect dis-similar secondaries in series to increase voltage provided the inter-winding break down voltage is not exceeded. Connecting dis-similarsecondaries in parallel is not a simple matter.
Indeed, very far from simple, and something that would normally only be done in exceptional circumstances, and by people who fully understood what they were doing.

Porque, please bear in mind that this is a DIY Electrics forum. That being the case, I would suggest that even hinting at the possibility of connecting dissimilar transformer windings in parallel is very inappropriate, and arguably irresponsible.

Kind Regards, John
You beat me to it. I remember working it out in University and the pages of calculations can't remember how to do it now without pulling out all the old books.

As far as DIY goes either the transformer states can be connected in parallel or they can't be connected in parallel. With two lighting tracks why would you want to connect the supplies together?

Anyway what happened to the dimmer. Last time this was posted she had a dimmer involved as well. Or is that a blond moment

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#### attractivebrunette

The data sheet should give the information you require this one for example states
Secondary windings can be connected in series or parallel or used independently.
but not all will be wired that way.

The transformer like this
is designed to be used within an enclosure and I would not select that type for powering lights. This type
are designed for lighting and have a lid which hides all the connections requiring a tool to access live parts.

Since there are two 12 volt tracks why do you want to join anything together? Clearly better to run independently.

You can clearly see on the top picture that transformer has all the connection details on the transformer its self I would think most are like that.

Thanks for everyone's help!

I'm only wondering where the SEC: 0-12V RED YELLOW and
0-12V BLACK GREY wires go.

Since there are four wires (RED, YELLOW, BLACK, GREY) but only TWO 12V tracks, which two wires do I join before connecting them to each track?

ie do I join the RED and BLACK together, and the YELLOW and GREY? or some other combination?

#### Mursal

In its simplest form

If the output from one 12volt winding is adequate to drive the load you are connecting, just connect as I have already explained. Forget about the other two wires.

The VI output from the winding must be larger than the required current for the connected load.

If the total load current required, is to large for one winding.
Connect half of the lights across one winding (red, yellow) and the other half across the other winding (black, grey).

How does that sound?

#### JohnW2

In its simplest form ... If the output from one 12volt winding is adequate to drive the load you are connecting, just connect as I have already explained. Forget about the other two wires.
Just to be sure thatthe OP understands ... I presume you don't mean to literally 'forget about' (i.e. ignore) the other two wires. They should obviously be put into a connector block or something like that - one wouldn't want them to be able to touch one another!

Kind Regards, John

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#### attractivebrunette

In its simplest form ... If the output from one 12volt winding is adequate to drive the load you are connecting, just connect as I have already explained. Forget about the other two wires.
Just to be sure thatthe OP understands ... I presume you don't mean to literally 'forget about' (i.e. ignore) the other two wires. They should obviously be put into a connector block or something like that - one wouldn't want them to be able to touch one another!

Kind Regards, John

I was just about to ask that! I should put the others in blocks

#### ericmark

Since there are four wires (RED, YELLOW, BLACK, GREY) but only TWO 12V tracks, which two wires do I join before connecting them to each track?
Each track will have two wires and two tracks so two x two = four. Have I missed something?

#### ban-all-sheds

You've missed attractivebrunette's unbelievable ignorance and incompetence, displayed on this site over and over and over again.

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