Low Voltage Garden lighting problem

[BuggBairn]

I'm looking to buy a 240-12Vac transformer to increase my garden lighting from the origonal 3 lights to 5 lights

I've bought a transformer from Maplins

http://www.maplin.co.uk/Module.aspx?ModuleNo=29782&doy=20m6D

its the 200VA model

I've tested the transformer with one lamp and it is very dim compared to one lamp of the origonally supplied transformer.


Could someonme with more than half a brain in there head steer me in the right direction.

A link to a certain transformer on the web would be ace.


Thanks in Advance

 

[jtaunton]

You're probably ahead of me on this one, but the old transformer was a 12V one, wasn't it.....

 

[BuggBairn]

You're probably ahead of me on this one, but the old transformer was a 12V one, wasn't it.....

The transformer supplied with the lights is :

PRI : 240 VAC 50HZ 15 VA
SEC: 12 VAC Max 10 VA

The one I'm tryin to upgrade with is :

PRI: 230V~50Hz 200VA COS= 0.99
SEC: 11.6V~eff MAX 16.5A

 

[jtaunton]

I'm guessing a bit here, without seeing the set-up, but if you are pluggin one bulb across the secondary on one transformer, and it is dimmer than on another transformer, then either you have not got as many volts, or the transformer cannot deliver the current.

Can you measure the voltage at both transformer outputs ? Is it about the same ?

 

[BuggBairn]

You're probably ahead of me on this one, but the old transformer was a 12V one, wasn't it.....

The transformer supplied with the lights is :

PRI : 240 VAC 50HZ 15 VA
SEC: 12 VAC Max 10 VA

Output 14 VAC

The one I'm tryin to upgrade with is :

PRI: 230V~50Hz 200VA COS= 0.99
SEC: 11.6V~eff MAX 16.5A

Output - Hmmm I'm having trouble getting a voltage reading from this one

There's 6 terminal and I'm taking my reading from one of each side, is that correct ??

Here's a pic of the one I just bought

 

[pdcelec]

Do you have the instruction manual? the transformer says 70-200VA. I am wondering if you may need to load it to a minimum of 70VA to operate it correctly.

 

[jtaunton]

Again, guessing, but I'd say that you should be able to read something between any one of the top three and any one of the bottom three. If you can't get a meaningful reading between any two terminals then the transformer is possibly knackered......

pdcelec makes a good point - try sticking a few more bulbs on in parallel......

 

[BuggBairn]

Just a ****y wee sheet of paper with the following

Input Voltage 220-240V/50 Hz
Input Current 0.65A by 150W 0.87A by 200W
Rated Power 150VA: 50-150Wattage 200VA: 70-200 Wattage
Output Vol;tage 11.6~ef
POwer Factor 0.99


To be honest I haven't connected it up to the proposed lights yet.

I bought the Transformer with the intention of using an overated unit so as to not fry it.

 

[breezer]

couple of things, since you said

I've tested the transformer with one lamp and it is very dim compared to one lamp of the origonally supplied transformer.

what was the single lamp you used (was it the same as your existing?)

you did connect it between the two outer most terminals didn't you

could be a dicky transformer

is new transformer on its own supply (plug) just for testing purposes?

get a multi meter and check out put voltage

(no offence intenede just you never mentioned as i asked, and as i am not there...)

 

[BuggBairn]

Cheers for the help and advice folks

I sacked the idea and took the transformer back to Maplins.

Ended up buying another seperate pack of lights, cable & transformer.


Is it just me or is it a right pain in the backside that you can't add on to these systems, you'll blow the transformer.

That was my origional intention and problem in the 1st place

No I'll have to run two cables from indoors of two transformers


Thanks again folks

 

[breezer]

there are several problems. mostly down to cost.


more lights=more current=bigger cables+ bigger transformer

so its easier to limit this buy supplying a "kit"

that said ring make "select a light" where by you select everything, but again, more lights = more cost

 

[alertelec]

Yes the kits are far cheaper than buying the parts seperately; but the bits are available.

I would have checked the minimum 70va load of the transformer as advised in a previous post.

 

[kendor]

post is a bit late now but here goes anyway, I'd be weary of using that type of transformer for your garden lights compared to a "garden lights transformer", reason being a case of supply isolation the original transformer supplied for the use of garden lighting will have been double wound and therefore a "step down isolation transformer" with physical seperation between mains supply and output.