[modeleng] Re: Electrical Problem
- From: The Sheppard Residence <peter@xxxxxxxxxxxxxxxxxxx>
- To: modeleng@xxxxxxxxxxxxx
- Date: Tue, 28 Dec 2004 00:17:50 +0000
Nice idea (and cheap), but it will probably suffer the same problem as
the last power supply. That is, I would expect it to be designed for a
non-condensing, average temperature (say 5 deg C to 50 deg C) environment.
I put it in a metal box on top of my shed roof, out in all weathers and
temperatures.
They seem to die fairly quickly when they are not in the right
environment :-)
Although, I will look into the feasibility of putting the power supply
into the shed and running the low voltage wires to the RA indicator.
Cheers
Peter
Pendragon wrote:
> Peter,
>
> I am in need of a 12 volt supply at about 10 Amps and had though of
> using a computer power supply, I wonder if the same thing would fix your
> problem......I was in Maplins today and saw such a supply that would
> give the 12 volts / 10 Amp supply I need....might be worth a though
> especially if you can pick one up at a car but or the like.
>
> Regards,
>
> IP
>
> Priest & Sons Model Engineers
> http://www.kinvermes.pwp.blueyonder.co.uk/p1.htm
>
>
> -----Original Message-----
> From: modeleng-bounce@xxxxxxxxxxxxx
> [mailto:modeleng-bounce@xxxxxxxxxxxxx] On Behalf Of The Sheppard
> Residence
> Sent: 27 December 2004 18:40
> To: modeleng@xxxxxxxxxxxxx
> Subject: [modeleng] Electrical Problem
>
>
> Sort of model engineering - well railway related anyway :-)
>
> I have an "RA" (Right Away) dot matrix indicator (from the "real"
> railway!) It is normally (on the real thing) driven off a 110v supply
> and internally there is a 110v/12v step down transformer. The light is
> generated by a 60W halogen bulb and uses fibre optics (approximately 30
> "dots") to spell the letters "R" and "A".
>
> As I am a sad anorak, I have it wired into the outside lights for the
> workshop (which themselves are controlled via infra red sensors).
>
> As I don't have 110v to hand I bypassed the 110v transformer and I was
> using a stabilised 240v/12v dc supply (until it expired - I suspect it
> wasn't designed to be used at the low temperatures we have had!)
>
> In looking for a replacement I found I had a large toroidal transformer,
>
> 240v/12 at 200VA (4 x 50VA windings) - I think it was actually designed
> to be used to drive quartz halogen bulbs. As the bulb wouldn't care
> whether dc or ac was used, it seemed an ideal solution.
>
> However, on several occasions it has caused the 5A lighting trip switch
> to operate. It also seems to happen when it is being switched off,
> rather than on.
>
> So, rather than the "inrush" current causing the trip to operate, is it
> the collapsing magnetic field? If so, what could I do to reduce the
> effect on the trip switch. (Capacitor/resistor on the secondary to give
>
> a time delay?)
>
> Cheers
>
> Peter
>
>
>
>
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