Which transformer for LED Pool light?

All,

I replaced my old 125W halogen pool light with a 25W LED version and was wondering if I should also replace my iron core transformer for a spare Possum I have lying around? It's also currently connected to a Relay channel.

Are there any drawbacks in doing this? What about isolation? Lightning etc.

Thanks,
Ingo

 

It's not 100% clear what the layout there is, so let me confirm the arrangement.

If I've got this right, you have an iron-core transformer of some sort that was driving your low-voltage 125W halogen pool light, and you've swapped the lamp out for a 25W low-voltage LED lamp. Now that you've done this swap, you're wondering if you should replace this iron-core transformer for a spare Tridonic Atco Possum (rated for 60VA) you've got in your box of tricks. Is that right?

A big iron core transformer running a small LED load like this is going to be pretty inefficient. I suspect that if you were to measure the power in that circuit you would probably find the transformer would be dissipating 10W+ or thereabouts.

The output from the Possum is double-insulated so the isolation should in theory be as good as the iron-core transfomer you're replacing. Having said that, lighting is a very powerful force and there's only a limited amount of things you can do to protect your equipment. If lighting is likely to be an issue then I'd suggest using the C-Bus relay to drive either an external relay or contactor (or a C-Bus Relay driver with external relays), with it's own power feed. This will give you a degree of electrical separation between all the C-Bus gear and that particular electrical circuit.

Compatibility between LED retrofit lamps and electronic transformers can be quite patchy, so it's best to test on the bench first before committing to the real install.

 

Thanks Newman, your understanding of my initial question was 100% correct.

The second part was just to find out if the isolation and protection would be as good as the iron core I will be replacing. If they are the same then I will do my bench test to check the compatability.