[modeleng] Re: Electrical Problem
- From: "Pendragon" <idpriest@xxxxxxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Mon, 27 Dec 2004 22:49:08 -0000
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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