thebogg Posted January 9, 2014 Share Posted January 9, 2014 I am currently using a gaugemaster controller to power my layout lighting but with 30 odd lights it is no longer capable as it cuts out after a few minutes. It is 12v-1.5amps max load. Can anyone suggest a transformer that would be suitable and power about 40 lights? Thanks for looking. Link to post Share on other sites More sharing options...
jimmer Posted January 10, 2014 Share Posted January 10, 2014 Optimus prime? I'lll get my coat.... jimmer Link to post Share on other sites More sharing options...
RMweb Premium Ray H Posted January 10, 2014 RMweb Premium Share Posted January 10, 2014 What type of lights are you using and what are you using them for? Is the rating of your transformer 1.5amp max. but about 1 amp normal? 1amp (A) is 1000 milliamps (mA). That should be more than enough to run thirty 30mA bulbs (30x30=900) and even 40x30 is only 1200 (or 1200mA) which I would have thought is within the capabilities of a 1.5A transformer with some spare capacity. I recall that grain of wheat bulbs are about 60mA so with forty of those to run you need a 2.5A transformer. Do you know how many bulbs the transformer will run without cutting out if you don't know the rating of the bulbs? We may then be able to estimate the bulb ratings if they're all similar. Link to post Share on other sites More sharing options...
PatB Posted January 10, 2014 Share Posted January 10, 2014 I've successfully used a cheapo generic laptop power unit for slot cars. Nice regulated voltage and stacks of current capacity. Have a look and see what Maplins can do for you. Another cheap, but less sophisticated, option is a car battery charger. Not one of the over clever ones that seems popular these days but the old style basic buzz-box which supplies ~14V DC to a couple of leads with croc clips on the ends. Current capacity will be way more than you need (10A peak and ~5A continuous is quite a reasonable expectation). I use mine for pretty much anything where I need roughly that voltage and it hasn't let me down yet. Link to post Share on other sites More sharing options...
Brian Posted January 10, 2014 Share Posted January 10, 2014 Hi If your lamps are all filament lamps you need to work on the 'rule of thumb' that each lit lamp will draw a maximum of 0.08Amp or 80milliamp. Then times the lit number by the 80 e.g. 40 x 0.08 = 3.2Amp Even if they are of a lower current rating of 0.06Amp 60milliamp per lit lamp 40 will demand a power supply capable of providing a minimum of 2.4Amp (2400milliamp). This loading is quite high and I would recommend that if you remain with filament lamps you split the lighting into three or more sub circuits of around 10 - 12 lit lamps per circuit. Protecting each sub circuit with is own series wired self resetting overload cut out. Like this example http://www.maplin.co.uk/p/10a-auto-reset-circuit-breaker-ak07h Maplin part No AK07H 1.0Amp CB. Your power supply providing a regulated 12 volts dc at 3.2Amp or more to the whole system can be a laptop PSU. Often the best prices for these is ebay.... Example of PSU http://www.ebay.co.uk/itm/VIP-12-12-Volt-DC-Desktop-Power-Supply-3-3-Amp-AC-DC-/221284093467?pt=UK_Computing_PowerSupplies_EH&hash=item33858f4e1b A mains lead is also needed as an extra for this particular one, but some are supplied with the mains lead. Either cut off the moulded dc plug on the low voltage lead and connect the two wires to a terminal block or obtain a matching sized dc socket. http://www.maplin.co.uk/p/21-x-55mm-single-hole-fixing-dc-socket-jk09k this is the chassis mounting version but in-line ones are also available http://www.maplin.co.uk/p/maplin-21-x-5mm-dc-power-line-socket-jk11m Note the dc socket size will depend of the power supplies plug size. In the example its 2.1mm but they can be larger! Take the PSUs negative wire directly to all the lamps, but feed the positive to one tag on each of the circuit breakers. The other tag on each breaker going to its own group of lamps. I would be looking to use as a minimum 24/0.2mm equipment wire for the return negative lead from all the lamps and the same sized wire to feed the CBs from the PSU. Then from each CB to its group of lamps I would use 16/0.2mm equipment wire. This size will be adequate for all current demands and help ensure a low volt drop too. Edited to add wire sizes Link to post Share on other sites More sharing options...
corax67 Posted January 10, 2014 Share Posted January 10, 2014 Optimus prime? I'lll get my coat.... jimmer Darn you beat me too it ! Link to post Share on other sites More sharing options...
corax67 Posted January 10, 2014 Share Posted January 10, 2014 I am currently using a gaugemaster controller to power my layout lighting but with 30 odd lights it is no longer capable as it cuts out after a few minutes. It is 12v-1.5amps max load. Can anyone suggest a transformer that would be suitable and power about 40 lights? Thanks for looking. Do you want dimmable or constant output? There are plenty of cheap uncased transformers available through the likes of Gaugemaster but you may have a situation where cased is a requirement, in which case laptop PSUs are a cost effective route to take. Link to post Share on other sites More sharing options...
thebogg Posted January 11, 2014 Author Share Posted January 11, 2014 Thanks for your help I think I will opt For the PSU option. Optimus prime? well it takes all sorts. Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.