I don't know what this has to do with solar power but it is
kind of interesting to see how electrical energy is
delivered in various parts of the world. I wish it was a
standard 220V worldwide but real life is never that simple.

Allen

-----Original Message-----
From: piclist-bounces@mit.edu
[mailto:piclist-bounces@mit.edu] On Behalf Of RussellMc
Sent: Friday, March 22, 2019 8:09 AM
To: Microcontroller discussion list - Public.
Cc: Reid, John (Oji Fibre Solutions); ApptechNZ;
ken@elecsyn.com
Subject: Re: [OT] Solar Power

On Fri, 22 Mar 2019 at 23:10, James Cameron
<quozl@laptop.org> wrote:

> On Thu, Mar 21, 2019 at 08:45:27PM +1300, RussellMc wrote:
> > [...]
> >
http://www.inference.org.uk/sustainable/book/tex/sewtha.pdf
>
> A side issue.
>
> On the 63rd page, marked page 50, it is said that "In
countries where
> the voltage is 110 volts, it takes twice as long to make a
pot of
> tea."
>
> In UK, it is said that a 230V outlet permits up to 13A.
So the
> limit is 2.990kW.
>
> In Australia, a 240V outlet permits up to 10A.  So the
limit is 2.4kW.
>
> What does the US have as a conventional pluggable cable
limit?
> Wikipedia suggests 115V and 15A, or 1.725 kW for NEMA 1-15
or 5-15.
>
> So that is 58% of the UK tea power delivery.
>
> Or 1.73 times as long?
>
> In the US real women probably use an outlet with access to
both side of
the 180 degree separated "phases" and make tea 13.8% faster.

Whereas NZ and UK and others have 3 phases (usually one or
sometimes two
phases per home) of (choose one) 220/230/240 VAC at 120
electrical degrees
to each other, the standard US (choose one) 110/120 V
'phases are derived
by centre tapping a 220 / 240V winding, so that each phase
is at 180
degrees to the other - so a phase to phase connection sums
the voltages to
give 220 /  240 Volt.

*Water heats at about 850* litre-degrees_C per kWh.   *

*<- store this useful figure in your brain.
(*
Actually 853 at 0 C and 100 C and 861 at 40 C, but, that's
water for you.)*

So an eg 2.4 kW element heats at 2.4 x 850 =3D 2040
litre.degrees per hour.

minutes x Watts ~=3D litres x degrees_C x 70

*         or minutes  ~=3D litres x degrees_C x 70/ Watts.
<- a keeper*

eg 2 litres of water heated from 20C to 100C  using 2.4 kW.

t =3D 2 x (100-20) x 70 / 2400 =3D 4 minutes 40 seconds.

_________________________________

I have two phases live in my hone - there long ago were
three when a prior
owner ran a two shift plastic moulding and ??? business in
the back yard.
The 'main' portion of the house runs on one phase and the
rear portion
(this office, downstairs workshop, some other) runs on the
other.
I have 230 VAC nominal phase-neutral in each case and 400
VAC phase-phase
should I ever choose to use it -  I never have. During the
occasional power
outage it is far more common to only lose the "front of
house" phase and
occasionally both together. Never, so far, afair (in 30
years) the rear
phase only. If a single phase outage occurs of-an-evening I
run an
extension cord from the rear of house and operate TV,
regrigerators and
misc lighting and laptops as requisite thereon. This PC is
already on the
"rear" phase.

What has this got to do with solar power ? :-)


       Russell
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