Date   : Mon, 31 Aug 2009 22:55:24 +0100
From   : mfirth@... (Michael Firth)
Subject: Leccy @ Acorn World '09

----- Original Message ----- 
From: "Ian Stocks" <bbcmicro@...>
To: "BBC micro mailing list" <bbc-micro@...>
Sent: Monday, August 31, 2009 10:45 PM
Subject: Re: [BBC-Micro] Leccy @ Acorn World '09


> Dave Moore wrote:
>> Anyway, if it turns out that 30A is all we have to play with, then my 
>> original
>> grand plans
>> <http://www.acornworld.co.uk/prep/AcornWorld2009_Power+Sockets+WiringPlan.png>
>> will need need to be toned down a bit (as I think we'd have been looking 
>> at up
>> to 55 amps).
>>
>> So here's an alternative, less-ambitious proposal:
>> http://www.acornworld.co.uk/prep/AcornWorld2009_Power_Reduced_Sockets+WiringPlan.png
>>
>> Would this still be pushing it? (I'm not an electrician so would welcome 
>> any
>> input). Bear in mind that across the other side of the room you'd have a
>> laptop, projector and PA.
>
> What are you basing your calculations on? Current usage per socket?
>
> I've just measured the consumption of a mono monitor & Atom using a
> cheap plug-in monitor (so take figures with a healthy margin of error)
> at 0.2A. Plugging a beeb in pushed it up to 0.3A. I can bring at least
> two of these plug-in monitoring devices, and I guess other people have
> such devices. I suspect if we keep an eye on total usage we'll be ok.
>
>
I agree - I think we need to work out what the typical power consumption of 
a Beeb (or Electron,
or Atom, and the 32-bit Acorn Systems) setup is, and then multiply that by 
the number of systems
present.

I'd have thought that even with a vintage Cub monitor, and an external PSU 
floppy drive, a Beeb setup
would only reach around 1A.

I'll put some of my bits on a similar plug in power monitor tomorrow, and 
post the results here.

I suspect that even for the 90ish sockets on the original diagram, you might 
still have leeway on a 30A
ring, provided that:
a) The whole 30A ring current is available in the room
b) Each socket is taking an average of less than 0.3A, or 80W.

Regards

Michael