low voltage trannys

[stanna]

Hiya All

Been advised by a mate that I should put enough lamps on a tranny so that the tranny is working at its max.

Using lamp holders with 10 watt \g4 bulbs and trannys are 10-60w output.

So this would put 6 of these lamps on one tranny.

This conflicts with previous advice received saying 1 lamp 1 tranny.

Any comments very welcome.

Thanks

 

[Taylortwocities]

What advice was that, then?
Probably it related to one 50watt lamp on a 60VA transformer? Surely not a 10watt lamp????

Do also note that a lot of the cheaper 60VA transformers will not start working unless you pull more than 20watts from them.

So yes 6 x 10watt lamps sould work off a 60VA transformer.


PS I guess you mean 12v lamps? Those are EXTRA low voltage, not low voltage.

 

[stanna]

Cheers for response

trannys are made by One Electrical with 10 year guarantee from WF. I asked for a good make and was told these are perfect and they never get any back.

There is only one connection so i assume i will have to use mini junction boxes if i want to put multiple lamps on one tranny.

Will helicon connectors do?

Cheers

 

[Taylortwocities]

Will helicon connectors do?

I have no idea. Never seen a helicon., what is the current rating for it/them.

60 watts at 12 volts thats ooh 5 amps. Is your heliwhotsit up for that as a continuous load, or will it fail and set fire to your ceiling?

 

[stanna]

Sorry misspelt should be Helacon connectors rated at 24 a

http://www.hellermanntyton.co.uk/products/classifications/products?PRODUCTID=148-90000

As these trannys are so cheap im happy to put one on one lamp but is this going to make them under perform?

Cheers

 

[ban-all-sheds]

Just a quick point - if you're in England or Wales installing these lights is notifiable.

 

[Taylortwocities]

Do also note that a lot of the cheaper 60VA transformers will not start working unless you pull more than 20watts from them.

 

[stanna]

Message received.

Cheers

 

[stanna]

Sorry about this i'm just double checking.

I have 3 trannys rated at 20-60VA dimmable, soft start overload protection. I need 9 lamps in the ceiling with 20 wattG4 bulbs for an ambient light effect. This will be enhanced by task lighting on a seperate circuit.

My plan is too site the trannys in an accessible location which means cable runs of up to 4 metres between tranny and lamps and put 3 lamps on each tranny.

Which would be best
1. run each tranny to junction box and then supply each lamp on its own cable from there. Therefore 3 trannys, 3 junction boxes, 3 seperate feeds from each junction box to each lamp.

OR
2. Each tranny to a junction box and one supply to the first lamp in each set and from there onto the next. So 3 trannys, 3 junction boxes and 1 feed from each junction box to daisy chain 3 lamps.

Using the online cable calculator im getting 1.0mm cable size.

Whats your opinion chaps?

Thanks

 

[stanna]

Can anyone give my circuit proposals the once over in my last post.

Cheers

 

[Taylortwocities]

The issue with mutiple lamps on one tranny is volt drop.
May mean that the lamps will get dimmer the further they are from the transformer.

The best way to get around this is to have the same length of cable from the tranny to each lamp (ie all connecting at the tranny rather than as a string of lamps). Also use larger cable than you think you'll need.

Your 10W lamps will pull around 1amp each at 12volts;, so if you have a string of 3, you'll draw 3 amps on the first section, 2 amps from the second and 1 amp on the third bit.

The volts will get less as you move down the string.

Given my ramblings, above, your proposal 1 looks better.

 

[stanna]

Ok Doke


Thanks for that. Im on with it using option 1.

Ta

 

[333rocky333]

Electronic transformers are usually labelled with the lead length, they do not usually recomend 4 metres.