Invisible <voi### [at] devnull> wrote:
> Stephen wrote:
> > Invisible <voi### [at] devnull> wrote:
> >> I'd say 3 AWG - but either way, it's less than 1 cm thick.
> >>
> >> Like I said, when they hook up the external generator, it comes with a
> >> cable well over 10 cm thick (!)
> >
> > A lot of that thickness will be insulation, shielding and armor.
>
> Probably.

Not probably but defiantly.

> The plug is physically larger than my head. The whole contraption looks
> like a giant's plaything has fallen out of the sky or something...

Yip and the reverse is true. In the old days, people who worked on high power
equipment thought that electronic connectors looked like toy stuff.

Stephen

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Phil Cook wrote:
> And lo on Fri, 09 Nov 2007 11:44:37 -0000, Invisible <voi### [at] devnull> did 
> spake, saying:
> 
>> Since we store stuff that has to be kept frozen, a power cut is a 
>> fairly major event. Our customers won't be too pleased if their $80 
>> million project has to be restarted from scratch because the stuff 
>> melted! So in the event of a power cut, a big truck comes along and 
>> dumps a huge lump of pig iron labelled "CAT POWER" outside our 
>> building, with a ridiculously huge cable and a comically over-sized 
>> plug on the end. (Seriously, the cable is thicker than some tree trunks!)
> 
> And what happens if the firm can't get you a CAT out in time? If it's 
> that crucial shouldn't you at least have a CAT UPS or equivalent to tide 
> you over.

The thing is:

1. The guys at CAT have a contractual obligation to arrive within X 
minutes of being called. If they fail to do this, they must pay us 
absurd amounts of money.

2. The freezers don't instantly heat up when the power is turned off. 
They have this thing called... thermal insulation. ;-) Not to mention 
the specific melting heat of water. (Do you have any idea how much ice 

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And lo on Fri, 09 Nov 2007 15:02:40 -0000, Invisible <voi### [at] devnull> did  
spake, saying:

> Phil Cook wrote:
>> And lo on Fri, 09 Nov 2007 11:44:37 -0000, Invisible <voi### [at] devnull>  
>> did spake, saying:
>>
>>> Since we store stuff that has to be kept frozen, a power cut is a  
>>> fairly major event. Our customers won't be too pleased if their $80  
>>> million project has to be restarted from scratch because the stuff  
>>> melted! So in the event of a power cut, a big truck comes along and  
>>> dumps a huge lump of pig iron labelled "CAT POWER" outside our  
>>> building, with a ridiculously huge cable and a comically over-sized  
>>> plug on the end. (Seriously, the cable is thicker than some tree  
>>> trunks!)
>>  And what happens if the firm can't get you a CAT out in time? If it's  
>> that crucial shouldn't you at least have a CAT UPS or equivalent to  
>> tide you over.
>
> The thing is:
>
> 1. The guys at CAT have a contractual obligation to arrive within X  
> minutes of being called. If they fail to do this, they must pay us  
> absurd amounts of money.

Yeah, but that's little compensation if as a result businesses stop using  
you and you fold

> 2. The freezers don't instantly heat up when the power is turned off.  
> They have this thing called... thermal insulation. ;-) Not to mention  
> the specific melting heat of water. (Do you have any idea how much ice  


I'm just wondering as to the overall cost of a CAT UPS over the cost of  
the contract to bring in a CAT generator, which would also run all your  
electrical equipment.

-- 
Phil Cook

--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com

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Phil Cook wrote:
> And lo on Fri, 09 Nov 2007 15:02:40 -0000, Invisible <voi### [at] devnull> did 
> spake, saying:
> 
>> The thing is:
>>
>> 1. The guys at CAT have a contractual obligation to arrive within X 
>> minutes of being called. If they fail to do this, they must pay us 
>> absurd amounts of money.
> 
> Yeah, but that's little compensation if as a result businesses stop 
> using you and you fold

I don't think you understand what I mean by "absurd amounts of money". ;-)

[As in, like, if companies *did* stop using us, we'd *still* have so 
much money it wouldn't even matter...]

>> 2. The freezers don't instantly heat up when the power is turned off. 
>> They have this thing called... thermal insulation. ;-) Not to mention 
>> the specific melting heat of water. (Do you have any idea how much ice 

> 
> I'm just wondering as to the overall cost of a CAT UPS over the cost of 
> the contract to bring in a CAT generator, which would also run all your 
> electrical equipment.

Well, I'm sure somebody will have looked at that and decided it's not 
worth it. (I would think that for more than 3 seconds of cover, you'd 
need a battery larger than our entire office...)

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And lo on Fri, 09 Nov 2007 16:08:36 -0000, Invisible <voi### [at] devnull> did  
spake, saying:

> Phil Cook wrote:
>> And lo on Fri, 09 Nov 2007 15:02:40 -0000, Invisible <voi### [at] devnull>  
>> did spake, saying:
>>
>>> The thing is:
>>>
>>> 1. The guys at CAT have a contractual obligation to arrive within X  
>>> minutes of being called. If they fail to do this, they must pay us  
>>> absurd amounts of money.
>>  Yeah, but that's little compensation if as a result businesses stop  
>> using you and you fold
>
> I don't think you understand what I mean by "absurd amounts of money".  
> ;-)
>
> [As in, like, if companies *did* stop using us, we'd *still* have so  
> much money it wouldn't even matter...]

Sounds like you need a power cut, a narrow road, a tree, and a chainsaw.

>>> 2. The freezers don't instantly heat up when the power is turned off.  
>>> They have this thing called... thermal insulation. ;-) Not to mention  
>>> the specific melting heat of water. (Do you have any idea how much ice  

>>  I'm just wondering as to the overall cost of a CAT UPS over the cost  
>> of the contract to bring in a CAT generator, which would also run all  
>> your electrical equipment.
>
> Well, I'm sure somebody will have looked at that and decided it's not  
> worth it. (I would think that for more than 3 seconds of cover, you'd  
> need a battery larger than our entire office...)

You'd think.

-- 
Phil Cook

--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com

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Invisible wrote:
> A0 paper.
> 
> As in, the largest standardised paper size that exists, at more than a
> meter wide. (2.5 feet by 4 feet, roughly.)
> 


(shorter_side)*SQRT(2).

-- 
Eero "Aero" Ahonen
   http://www.zbxt.net
      aer### [at] removethiszbxtnetinvalid

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Invisible wrote:
> scott wrote:
>>> (Woah - 63A? o_O Anybody know what thickness of copper it takes to
>>> handle that kind of currentl? That's gotta be more like a girder than
>>> a wire!)
>>
>> Roughly double your standard 13A cable would do...  Look at the cable
>> going to the starter motor on your car, that's usually 100A or so.
> 
> 1. A car runs on 12V electrics, not 250V. Does that make a difference?

No.

> 2. Is maximum load proportional to diameter or cross section area? (The
> latter is quadratically propertional to diameter.)

Cross section area.
(But I don't know how it is with really large
cross sections and currents.)

-- 
Tor Olav
http://subcube.com

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Invisible nous apporta ses lumieres en ce 2007/11/09 07:36:
> scott wrote:
>>> (Woah - 63A? o_O Anybody know what thickness of copper it takes to 
>>> handle that kind of currentl? That's gotta be more like a girder than 
>>> a wire!)
>>
>> Roughly double your standard 13A cable would do...  Look at the cable 
>> going to the starter motor on your car, that's usually 100A or so.
> 
> 1. A car runs on 12V electrics, not 250V. Does that make a difference?
To my knowlege, only on the insulation.
The diameter of a cable is dictated the number of amps, it's insulation by the 
volts.
> 
> 2. Is maximum load proportional to diameter or cross section area? (The 
> latter is quadratically propertional to diameter.)
Would be the cross section. But you have proportionatly less surface area to 
evacuate any generated heat.
> 
>> Can't you print it out tiled, ie 8 A3 sheets (or however many it is) 
>> then just put them together?
> 
> Well, in principle yes. In practice, I very much doubt you'd ever get 
> the pieces to line up properly. (Ever notice how map books *always* put 
> the place you want to look at in the crease?) Plus I'm having enough 
> trouble finding somewhere to put an A3 printout without it getting 
> crinkled up... :-S
> 
> Apparently the planners have access to an A0 printer. I don't even want 
> to imagine what that must cost... ;-)
The price is irrelevent when the equipment allows you to do your job. Also, 
often, the highest priced options turns out to be the cheapest... in the long run.
Many mechanics can tell you: "I can't afford to buy any but the best tools 
available, whatever the price!"
This is also true for engineiring firms.

-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when you invented glasses that can be 
configured to use variable resolution (eg. 320x240, 640x480, etc.), with POV-Ray 
style switches for other effects (eg. anti-aliasing, radiosity, etc.)
Vimal N. Lad / Gautam N. Lad

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Alain wrote:

> The price is irrelevent when the equipment allows you to do your job. 
> Also, often, the highest priced options turns out to be the cheapest... 
> in the long run.

I wish somebody could explain this to the idiots I work for...

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> (Woah - 63A? o_O Anybody know what thickness of copper it takes to handle 
> that kind of currentl? That's gotta be more like a girder than a wire!)

If it's less than 100 feet maybe #8? (~3 mm)

> 1. A car runs on 12V electrics, not 250V. Does that make a difference?

Yes, lots. Voltage is the size of the elephant, amperage is how fast he's
going when he runs you over. I think many cars will pull more than 100 A
cold starting though.
100 A * 12 V = 1200 W (~1.6 hp)
100 A * 220 V = 22 KW (~29.5 hp)

> 2. Is maximum load proportional to diameter or cross section area? (The 
> latter is quadratically propertional to diameter.)

It's proportional to the surface area. Thus all the stranded and braided 
wire.

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