Garden Railway Forum

Hi everyone,

I'm in the process of scratch building an electric shunter, and have picked up the IP engineering speed controller as I fancied a bit more control whilst keeping costs relatively low.

It's just that my electronics knowledge is letting me down. With regards to the 'electronic chip' supplied with the kit; it states (in the instructions) to bolt it to a piece of metal. Once bolted to the piece of metal, is it just a case of attaching the underside to the chassis of the loco to keep it secure?

If anybody can give me some advice on this or even attach a photo of their completed kit it would be greatly appreciated.

Happy running

The metal is required as a heat sink for the chip, without it it will get very hot and possibly burn it out.  I fitted one of the speed kits to a Rapier I was building, perplexed me too, it was only after building and during running I realised what the piece of metal was for!

As for where it goes one built, that is up to you, but somewhere accessable so that the air flows over it (and thus hopefully taking some of the heat with it) would be the best idea. Mine is bolted underneath my Rapier in front of the fron axle.

I can get a picture for you but it will have to be tomorrow now

LlanpwllBrynwyn:73610 wrote:The metal is required as a heat sink for the chip, without it it will get very hot and possibly burn it out.  I fitted one of the speed kits to a Rapier I was building, perplexed me too, it was only after building and during running I realised what the piece of metal was for!

As for where it goes one built, that is up to you, but somewhere accessable so that the air flows over it (and thus hopefully taking some of the heat with it) would be the best idea.  Mine is bolted underneath my Rapier in front of the fron axle.  

I can get a picture for you but it will have to be tomorrow now

Well, that puts my mind to rest; perhaps I will actually be able to get started once the plasticard arrives!

Not to worry about the photo, I couldn't have asked for a better answer. To allow for cooling I think I will borrow your idea and attach it outside of the chassis.

Many thanks!

This is a similar speed controller kit from Cambrian Models - the transistor is fixed to a standard heatsink, you can get these from Maplins etc or just make one from an offcut.