12v lights very dim after replacing transformer

[pentoman]

Hi all,

As recommended here, I just replaced the transformer in my 12v bedroom light from this one //www.diynot.com/forums/viewtopic.php?p=94760#94760
which would buzz loudly when used with a dimmer (even if on full brightness).

I put in an Aurora "Dimmable Electronic Transformer" of 150W and 12v found here http://www.aurora-lighting.com/previous_site/products/transformers/euro_right2.htm . This should be ok as there are four 35W halogen bulbs on the rail = 140W, which is close to 100% as desirable for a dimming application.






However, with this transformer full brightness is very dim (using a normal on off switch). At first it's 80% what it used to be, after 5 minutes off being on they reach about 60% brightness and are pretty useless.
AARRGHH


Why is this??


I even took one bulb off to see if it's too much load, but it's still dim. I checked connections are tightly screwed together and the wires I'm using are very thick so must be fine.


thanks

Russ

 

[softlad1971]

Have you got a multimeter? If so measure the volts output from the transformer when the bulbs are on. Post back your results.

 

[breezer]

what is the model # of the one you have?

 

[pentoman]

what is the model # of the one you have?

It's the 150W AU-150 on that page.

I tried measuring the voltage across both the 'rails', and it's 7V AC, this is with 3 of the lights on it.

My thought is that the transformer input has 2 screw-down type holes (simple), while the output had 6 of them arranged next to each other. The instructions are useless but I presume these are just 3 pairs of parallel connections

The two wires to the rail & the bulbs are just connected to the 1st and 2nd holes.


thanks

Russ

 

[softlad1971]

well, You have found why they are dim.. 7volts is just not enough. Have you tried just one lamp as the load? It looks like the transformer is being loaded too much or faulty and not up to the rated output

 

[plugwash]

or could be that they are seperate secondrys/outputs and need to be loaded seperately.