LGB 18 volt transformer alternative..

[Ianjd59]

I'm in the process of upgrading my current control system, & to this end recently bought an LGB 5A controller (51070) from eBay. I was rather shocked to discover that LGB want £150 for an 18V transforner! Now can anyone tell me if this is all the unit is - a transformer - or is there any other cleverness inside? Having built more than a few power supplies in the past, both proffesionally & recreationally, a quick browse through CPC & similar reveals that an 18V 6A AC power supply with the appropriate protection can be put together for around £30. Anyone know what else is in the box?

 

[Gizzy]

I think it's more a case of paying for the name LGB and the quality, rather than some clever electrickery.

I certainly can't see it being any cleverer than what you can by as a kit from CPC, so your cost saving there is because you are building the Transformer yourself, rather than a chap in Germany or where ever LGB manufacturing is now outsourced....

 

[whatlep]

I'm in the process of upgrading my current control system, & to this end recently bought an LGB 5A controller (51070) from eBay. I was rather shocked to discover that LGB want £150 for an 18V transforner! Now can anyone tell me if this is all the unit is - a transformer - or is there any other cleverness inside? Having built more than a few power supplies in the past, both proffesionally & recreationally, a quick browse through CPC & similar reveals that an 18V 6A AC power supply with the appropriate protection can be put together for around £30. Anyone know what else is in the box?

There's a transformer plus some circuitry which ensures you get a stable 18 volt output no matter how many amps you drag out of the device. If you try various manufacturer's transformers side-by-side, you'll find that isn't always the case. If you've built these beasts before, you'll know better than I why that should happen. You're also paying for someone else's time of course. Presumably you have factored the "opportunity cost" of yours into the equation.

That said, I agree that GBP150 at full retail price is a nonsense for what you get. The good news is that it's rare to have to pay more than GBP90 for a second hand unit and there are plenty about. If you're patient, you'll doubtless find one for less.

 

[LittleRedTrain]

GRS have one in their second hand for £99

http://grsuk.com/forum/topic.asp?TO..., I'm just waiting for them to get stock in).

 

[stevedenver]

got the unit you refer to-

thats all it does-but it does have a red and a green light-as well as the red LGB box and logo!!! (which makes it worth it) !LOL

actually, the two work very nicely together and ive been happy with mine
it appears to be a quality unit-its very heavy and silent too
i paid $129 US for mine, new, about 2 years ago as a back up for my others and for use at holidays-

 

[mike]

the lgb ones full off lgb magic

 

[minimans]

the lgb ones full off lgb magic

Actually Mike it's full of LGB smoke.....................You can tell because if you let the smoke out it stops working!!........................Very old joke courtesy of Joseph Lucas Ltd............

 

[mike]

now THATS magic!

 

[simon@mgr]

Internal smoke is the only thing which keeps many things working, once it's converted to an expensive brown smell, most things stop working!

 

[spike]

If the transformer is just for AC then any cheap toroidal or normal tranny will do.
RS do one or two that will give you approx 6Amps, you will need a box to house it and some form of
terminations for input/output. Plus you will need some form of protection ie fuses or circuit breakers.
I would put a fuse in the primary and one in the secondary circuit as well.
These fuses will be different types, the primary rated for inrush current, the secondary can be a normal fuse.

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0504072 < Link To Standard tranny 150VA 8Amps £21.29

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2238033 < Link To Toroidal 120VA 6Amps £17.53

whatlep mentions the stable voltage.
Yes this is the regulation of the transformer, loaded voltage against noload voltage.
Transformers do vary on this and how they are constructed affects the regulation.
Normal regulation would be about 10%........so an 18Volt transformer would have approx a no load output
of 19.8Volts.
You most likely pay more for better regulation

 

[Montblanc]

For those who do not have the skills to build a trafo themselves, power supplies designed for laptop computers are a good cheaper alternative to LGB units.

Jean-Pierre

 

[Ianjd59]

As a bit of a postscript to this one, I found a 250 VA toroidal transformer at work, which quite fortuitously has two 18V secondarys. It drives my 51070 a treat, with the bonus that I have another 18V 6A winding currently unused which could be used for all manor of things, or a fail-over if the first one goes U/S! I just need to put it in a box, add a bit of protection, & away we go.
As a sort of caveat to Montblancs message, most laptop PSUs are DC, for the LGB control system, the PSUs are AC output.

Ian.

 

[stevelewis]

Theres an almost new LGB 50110 Transformer listed in the sales section

 

[Gavin Sowry]

the lgb ones full off lgb magic

Actually Mike it's full of LGB smoke.....................You can tell because if you let the smoke out it stops working!!........................Very old joke courtesy of Joseph Lucas Ltd............

8| Ah, Joseph Lucas, ... the Prince of Darkness!

 

[Montblanc]

Yes, of course Ian you're right ! I was only thinking analog control.

Jean-Pierre