Change Of Transformer From Traditional To Electronic.

[dubbySwords]

Hi!
I have a traditional transformer which no longer works. I am now in the process of buying components to replace it. The old transformer goes from 240v to 11.4v (300VA). It has 4 circuits attached. I then went out and bought 3 105VA electronic transformers (this I realise is a mistake I should have bought 4). These new transformers do not have an earth. The old transformer had an earth on both sides i.e. primary and secondary.
- Have I bought the completely wronge products?
- If not what will I do with Earths?
 

 

[Marvo]

Maybe the new transformers are in a plastic enclosure or ClassII and therefore don't require a CPC connecting.

 

[Doc Hudson]

Welcome to the forum. The 230v to 12v transformer will be isolating the supply from the load as well as adjusting the voltage. There should be no earth connection from the load directly to the supply. Some transformers may have an Earth terminal to 'park' the unused wire but typically the output is just a 2core flex. Are these transformers for some recessed spot lamps by any chance? The 12v lamps themselves will not require an earth connection. You will need to ensure that the output flex to the lamp is large enough for the increased current. When a transformer reduces voltage it also increases current, as no power (other than negligible losses) is consumed by the transformer so power in is approx power out. The manufactures instructions with the transformer should detail how it is to be wired up. If you are in any doubt it may be best to get an electrician to have a look.

Doc H.

 

[SLIPSHOD & SLAPDASH]

Instead of replacing those parts have you considered replacing the lamps with GU10 LED' It will pay for its self in no time.

 

[ProDave]

Something worries me here.

You have ONE old transformer.

You have FOUR circuits.

Are you saying therefore that it's the 12V side that's switched to turn the circuits on and off?

And you are replacing it with FOUR 105VA transformers. Presumably one per circuit.  So I take it you are now modifying the wiring to switch the mains feeding the transformers now?

(Please do not tell me you are going to connect the 4 new transformers in parallel)

 

[SLIPSHOD & SLAPDASH]

How did you come to that conclusion Dave. It appears there was one tranny with 4 cables connected to the output , he bought 3 new trannys  to match the output but realised due to the cable configuration 4 are needed.

PS, he has posted this on  a few forums.

 

[ProDave]

If that's the case. I would not have described it as 4 circuits. It's ONE lighting circuit if that's how it was.

 

[steptoe]

sounds like very possibly a central torodial Tx  methinks,  :C

 

[Steve3948]

With 4 or more lights, so how many lights are off each leg I wonder.

 

[SLIPSHOD & SLAPDASH]

No mention of lights by the OP ;    Anyhow, whats the bets this is another 'One hit wonder' ?

 

[aSmith]

Great question regarding[SIZE=120%]Power transformers[/SIZE] . Thanks.....

 

[SLIPSHOD & SLAPDASH]

No mention of lights by the OP ;    Anyhow, whats the bets this is another 'One hit wonder' ?

I win, have to buy myself a pint   :facepalm: