In message , Ron
writes
On 06/02/2012 13:18, Arny Krueger wrote:
"Mike wrote in message
...
In articlePImdnRhFWezLuLHSnZ2dnUVZ_sSdnZ2d@giganews. com, Arny Krueger
writes

I'm not so sure about rings, but the doubled voltage looks good to me
given
that I would have enough appliances that ran on 240 volts to be
interesting.
I don't.

Think about it - your kettle would boil in half the time :-)

I get it. However, the 2-3 minute boil times I get with our current
technology seem to work out well enough.

I can boil 12 ounces of water in about 2 minutes in my 1200 watt microwave.

I can boil almost 2 liters of water in about 3 minutes in a 1500 watt
plastic pot with a built-in heatnig element.

In both cases the starting temperature of the water is about 45 degrees (F).

When I have people over for tea I set the pot to boiling when they arrive
and then reheat it in a few dozen seconds when needed.

A colleague went to work in the USA and complained about the weedy
kettles over there that take forever to boil. I suggested he take a UK
230V kettle over with him and run it off an extension to his stove
connection (i.e. 220V). Dunno if he ever bothered.

Seems like overkill, given the alternatives.


Oh good, we're going to argue about who can boil a kettle the
fastest... you couldn`t make it up!

OK then.

Assuming it survives long enough, a 120V kettle run on 240V will boil in
less than a quarter of the time. [Note 'quarter', not 'half', as twice
the voltage will provide four times the power.]

Conversely, a 240V kettle run on 120V will take more than four times the
normal time to boil. In fact, it literally could take forever to boil. I
know this to be true as I once took a single-voltage UK travel kettle on
a holiday in the USA!

These apparent anomalies are because, unless it's perfectly insulated,
as a kettle heats up it will radiate more and more heat.

Consider the case of the 240V kettle on a 120V supply. The rate of heat
radiation eventually may balance the rate of electrical input, so a
state of equilibrium is reached before the kettle boils. No matter how
long you leave it (or even watch it), it will never boil. It's therefore
a pretty good guess that, on a 240V supply, a 120V kettle will boil in
less than half the time.

BTW, for my next trip to the USA, I made sure that I took a dual voltage
kettle. I can confidently report that, when on the correct voltage
setting, it seemed to boil just as quickly as it had done in the UK.
--
Ian