Blown AC - AC Adaptor

Moral of the story; don't buy Chinese goods. They invariably use inferior materials.

When you buy cheap, you buy twice. When you buy good quality equipment it is still working long after you have forgotten how much you paid for it.

AlanShaw: 
 

Legh, this needs to be AC out, I may have this wrong, but I thought Switch Mode Power Supply's were DC out.

Going back to Mike's idea of a Toroidal Transformer, and he has listed the 80VA version, is there anything to be gained by going up to the 100VA or 120VA version, going from 80VA to 120VA only increases the cost by £4.00

well it will run cooler if it is over-sized, but you need a bigger box. ? Don't  go too mad.

 If you use a toroidal tranny be aware that the in-rush can be quite something (more than 10 times steady state while the magnetic field is being established) so you probably will need the 13A fuse, not a 3A one, and take care not to form a 1 turn short circuit by bolting through the centre to metal work that then completes an unintended  full turn. Either plastic cable ties or a mushroom post type mount depending on weight, Do not do this - the dotted lineshows the fault path.

This method is OK though, apart from being American picture

Mike

This method is OK though, apart from being American picture

I think pretty much everything about that second picture is wrong, apart from the way the transformer is mounted!

 I spoke to a company today specialising in transformers etc. from Bury St Edmunds.

Their technical did say that my transformer wasn't up to the job, but then went on to say that if it was one of theirs, it would probably run for an hour before it starts developing faults.

So they suggested a

So I have order one and I'll give it a go.

 

AlanShaw: 
 

Legh, this needs to be AC out, I may have this wrong, but I thought Switch Mode Power Supply's were DC out.

Going back to Mike's idea of a Toroidal Transformer, and he has listed the 80VA version, is there anything to be gained by going up to the 100VA or 120VA version, going from 80VA to 120VA only increases the cost by £4.00

Its not impossible to convert ac to DC and then back to ac by using inverter circuitry. Depends whether or not you require a paper weight as part of your design..

Legh

I assume the AC is  only there to provide the voltage and they're relying on internal diodes in the lamps for rectification. If so why not just use any suitably rated DC supply?

The under hood lamps are G4 Halogen, I am not certain what the lamps are which light up the dials because apart from the very top tip of the lamp, they have been encased in heat shrink tubing. I did try an Aurora ac / dc transformer loaned to me by an electrician, but it failed to illuminate any lamps.

@AlanShaw That link is for the 24volt model. I hope you ordered 12V, or the lamps will have a very short bright life.

Mike.

I've just seen that, but whilst that is the transformer I purchased, there are 4 terminals on the outputs, 0v, 12v, 0v, 12v. So, according to the manufacturer, the output can be 12v or 24v.

This seems to be resolved now, I have fitted the above transformer and have run these lamps for over 24 hours now without any problem.