Date   : Sun, 30 Oct 2005 22:36:59 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Computer Museum gets cash from Gates

David Hunt wrote:
>>-----Original Message-----
>>From: Majordomo List Manager [mailto:majordomo@...] On Behalf Of
>>Jonathan Graham Harston
>>Sent: 30 October 2005 00:25
>>To: bbc-micro@...
>>Subject: [BBC-Micro] Re: Computer Museum gets cash from Gates
>>
>>
>>>Message-ID: <435D1844.2060106@...>
>>
>>Jules Richardson <julesrichardsonuk@...> wrote:
>>
>>>Jonathan Graham Harston wrote:
>>>
>>>>How much space do you need?
>>>
>>>We're aiming for somewhere around 12,000sqft - 10,000 for exhibition
>>
>>That's about a magnitude more than I have access to.
>>
>>
>>>space / public archives, and 2000 as workshop / stores. (ideally already
>>>with 3-phase power, we're rather over the limit of what we can do with
>>>domestic mains! :)
>>
>>Have you thought of using a phase tripler? Either a hunking great
>>capacitor and inductor to advance and retard the phase, or a
>>single phase motor driving a three-phase generator.
>>
>>--
>>J.G.Harston - jgh@... - mdfs.net/User/JGH
>>There are three food groups: brown, green and ice cream.
> 
> 
> A phase tripler will not increase the available power, it will merely
> distribute the available power (minus overheads) over three phases. 
> 
> There is a hint in the "over the limit with domestic mains", perhaps the
> quest is for more power.

Yep, we're hitting the limit on the single-phase into the building. Or 
were, given that we've lost use of that building and are awaiting more 
space elsehwere on site - remains to be seen what the power situation 
will be, but I expect it'll be single phase again.

A single drive on an old DEC is around 20A draw at startup, so it 
doesn't take a lot to trip the breaker if there are a few other big 
machines running at the same time.

We've got very little actual 3-phase stuff though. An old drum-store 
unit, a VAX 6000, and the ICL 2966 mainframe. The rest is all single 
phase, just power-hungry in a lot of cases!

> Mind you, at over 20kW - must be a fun electricity bill...

Well we're lucky in that we don't pay it :-) But the big stuff only ever 
ran at weekends - but all it'd take would be for people to be working on 
three large machines say and the mains couldn't cope. Having to 
power-cycle stuff in a certain order so the breaker didn't trip used to 
get really annoying!

cheers

Jules