EddScott

I need a 18V 8-10 amp transformer and I need it in an enclosure. Input is 240V

I'm building a railway and the controls for the track points need 18V and 8 to 10 amps to throw reliably.

I've tried laptop supplies and a bench power supply but the circuit protection on these things cuts in too early because there is a load when turned on.

Hence, I need a simple transformer without current protection - the wiring is sound BTW.

FlightMan

EddScott

Eh?

alcazar

iTrader: (2)

Tried any of the places that do DCC supplies? They tend to sell large output transformers. There's a good one near Lincoln.......

Digitrains for Digital Command Control | Digitrains

18V at 8A, what sort of motors are you using? Or are you trying to throw about ten at once?

Thought of a CDU?

john_s

iTrader: (1)

Make your own?

Transformer, rectifier, couple of caps, and a box to put it in. Add a couple of fuseholders and a switch if you want to make it look tidier.

EddScott

John S - Well I would but I'm not confident enough to do it myself. I'd rather pay a bit more and get someone else to do it properly or an off the shelf job. As the layout is in the loft I don't really want any more electrical hazards up there than the layout itself - its all switched, smoke alarms, fire extinguisher just in case.

Alcazar - I use these. They aren't exactly CDUs but have more functionality (panel LEDs etc)

MASTERswitch Electronics

The V2s work for single points or passing loop points and the MS+ work for points facing each other (The frog polarity is changed via a switch either on the SEEP PM1 or Peco PL10). Mostly SEEP PM1 but have a few Peco motors in the fiddle yard.

Max motors throwing is 2 and I have then all throwing at 18V (lower they don't throw 100%) and about 8 amps (if its 4 amps per motor)

The laptop supply and Bench PSU all worked OK with 4 or so masterswitches but any more and the protection would kick in as there was a load when turned on. If I added each masterswitch after the power was turned on, it all worked fine. Its the initial load thats causing the grief.

Leslie

Sounds like a lot of amps to work model railway points though.

Les

mikef04

iTrader: (7)

try here we use this at company at work pretty much everyday. you shoud be able to find what you want Welcome to rswww.com Your search for 240v - 18v transformer

EddScott

The thing is the motors really aren't very efficient and positioning of the motors is not easy and unless they are in exactly the right position, they can suffer binding problems which then makes the load required to throw them that bit higher.

I can throw most of them at 16V and with a max current of about 6A but I'm looking for 18V to allow some headroom - I can use upto 20V but the controllers get warm.

The current is a momentary requirement to throw the point motor so its not a constant demand. The motors are just metal cores thrown back and fore by induced coils - I don't know the right terms.

I've found a 18V 5A encased transformer which may do the job.

alcazar

iTrader: (2)

They are called solenoids, Edd.

I have a large DCC transformer bought from Digitrains, 5A, they do one that goes up to 10A IIRC, for longer/larger DCC layouts or Gauge1 stuff.

If your special switches don't have a fuse, DO fit one, won't you? That sort of current cuases almost instantaneous heating.........

BTW: CDU's tend to be a LOT better at throwing sticky pointmotors. They can produce a HUGE jolt to one.

Leslie

All understood Edd, they do make variable voltage power supplies of up to as much as 25 amps for radio amateur use. Bit pricey but it would do the job.

Les