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Re: Generators and switch mode power supplies
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I'm on Energy Australia's network. Significant outgages are not that
common, but they do happen. A friend was without power for an extended
period because of the Chatswood substation fire in 1999. That fire
affected 23,000 people.

There are annecdotal reports of transformers being subject to ad-hoc
cooling with fire hoses to prevent them from overheating. This doesn't
lend confidence that the infrastructure is up to the task of handling
high temperatures.

Part of Victoria's recent power problem arose because Basslink
apparently cannot operate at full capacity in high ambient temperatures
(that is, exactly when it's likely to be most needed).

And of course, from the USA and UK and Europe (Switerland/Italy) we've
seen how power systems can have cascading failures that can take 24
hours to put right. Thought at least we're not likely to see outages
caused by freezing rain.

After the UK had its huge windstorm some 20 years back, some country
properperties were without power for a couple of weeks. I my self was
without power for 12 hours or so. One doesn't realise just how dependent
one is on power until it goes off. Even our stove was electric. I ended
up making tea by sticking a cup of water next to a gas fire (I prefer
electric fan heaters. I'd kept the gas connected, and paid the service
charge, just in case).

I also lived in the UK during a year long miners' strike, and we had
rotating blackouts lasting three hours on several nights a week. That
was a real pain.

Here in NSW we were fortunate that the heatwave occurred most severely
at the weekend when power demands tend to be lower. Had it occurred a
couple of days earlier, NSW reserves would have been stretched.

And of course there's the bushfire season, where bushfires can
compromise transmission lines (and did so last year, or perhsp a few
years before - Parliament House got cut off!).

My main concern is an extended power loss during a worse heatwave then
the one we've just had. I'm not trying to run the entire house - just
the study, with its airconditioning and computers, which has a floor big
enough to drag a a matress or too into to sleep on if the outgage
continues into the night.

How much it's really worth spending on protecting against something that
may never happen, well that's another question, but the price is not
just to address the issue when it arises, it's, like insurance, to
provide assurance that the risk is being managed, one way or the other.

Sylvia.




Re: Generators and switch mode power supplies
hs so the supply's not exactly parlous where I am.
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I just worry about my own provider. If I was in the countryside anywhere,
then I would regard a number of diesel generators as absolutely
essential.

It really vcomes down to economic rationalism. If you can bill
$500 per hour, then your own serious UPS with backup generator and
250litre fuel tank is probably justifiable*.

But if this is just a home userwith an internet adiction, then a
laptop with prepaid wireless access and spending the night in the
knocking shop, woops Formula 1 motel probably makes a lot more
sense. Telstra has one of their WAP accesspoints just across the road from
the knock shop at McChuckies.

* The trouble is where do you stop? Most people do not think about where
they are going to store the 20, 40, 60l of petrol. Someone thought of
running his on mains gas, but what do you do if we have a WA supply
incident. You could end up with more money invested than in your house.

Re: Generators and switch mode power supplies
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Though that can turn out to be needless upheaval for what turns out to
be only a 2 hour outage.

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A mains gas outage is only an issue there if the power goes off at the
same time. Could happen, I suppose, but it's not very likely.

The problem with storing petrol is that it goes off. There are
additives, but even then the life is only one or two years. So you keep
having the recycle the stuff. I was looking at LPG. Even a 3kg tank
would run a 2KW generator for 6 hours (according to the specs). Also,
you can to go your local servo and do a tank swap even if the power is
out (which stops the petrol pumps).

Sylvia.

Re: Generators and switch mode power supplies


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that's life.



Really. I was under the imprssion that it wasn't a problem in Australia
for small motors. I'm currently on the last 5l of 20L purchased 3 years
ago and the shredder is happy.

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That is only a problem when you have misplaced the funnel and have to pout
it on the side of the empty vehcile and hope that most of it ends up in
the tank.

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What brand and model of generator? I last asked Advance Power a decade ago
and they said $400 on top of the generator price to have it converted.

Re: Generators and switch mode power supplies



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**LOL! Sorry, I just had a vision of that Cheech And Chong movie, where they
filled the gas tank of a classic 1970s car (convertible Mustang, if I'm not
mistaken) from a garbage can. They, too, failed to use a funnel (or a
filter). They results, when lighting a joint, were, er, explosive.


--
Trevor Wilson
www.rageaudio.com.au



Re: Generators and switch mode power supplies
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You have to remember to do it, though.

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http://www.apower.com.au/newproducts/lpggasmate.htm

Note that that's on their "New Products" page.

However...

I've just received a reply to my email asking about price, to be told
that they do not make a LPG 2.2KVA generator any longer, with their
smallest LPG model being a 7.5KVA.

Sylvia.





Re: Generators and switch mode power supplies



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**How big is your air-con and is it an inverter type?


--
Trevor Wilson
www.rageaudio.com.au



Re: Generators and switch mode power supplies
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960W, 5.1A. Inverter type.

Sylvia.

Re: Generators and switch mode power supplies



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**Make certain you do not connect a refrigerator to it as well.


--
Trevor Wilson
www.rageaudio.com.au



Re: Generators and switch mode power supplies
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I wasn't planning to, but is there some specific issue, other than
starting current, that you're concerned about?

Sylvia.

Re: Generators and switch mode power supplies
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  Some fridge compressor motors are very frequency sensitive, forget
which type though, and can easily burn out when running off generator
power unless the frequency is close to 50Hz. I expect an inverter type
generator would solve this though.

Re: Generators and switch mode power supplies


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**Nope.


--
Trevor Wilson
www.rageaudio.com.au



Re: Generators and switch mode power supplies

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It's only a real problem with higher compression and especially with higher
octane fuels. The more volatile components evaporate first.
You should run the engine every now and then in any case, so that burns a
little fuel.

MrT.





Re: Generators and switch mode power supplies
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  Not to mention fungal growths in the tropics, especially with
distillate.

There is some common food preservative that allows fuel to be stored
free of bacteria and fungus: a spoonful per 200L drum.

   It may be worth check what your household insurance states about
stored fuel and natural gas bottles: they have been getting weird
lately in that regard.

Re: Generators and switch mode power supplies


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that was sort of what I understood.

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Yep as it is unpleasent having to break one down if you can not get the
sludge out.

.

Re: Generators and switch mode power supplies

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One should do that anyway for a backup generator - the time it's needed
is not the time to find that it no longer works.

Sylvia.

Re: Generators and switch mode power supplies

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a

And the less often you run it, the less likely it will work next time you
try!

MrT.



Re: Generators and switch mode power supplies
On Sun, 08 Feb 2009 23:19:02 +1100, Sylvia Else

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<snip>

That was being done in QLD by energex IIRC. The courier mail picked up
on it and actually published photos of those green sprinkler hoses
being used to cool down transformers at a substation.

Re: Generators and switch mode power supplies

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what exactly do you want to use it for?
Equipment?
the power requirements of each item?
duration?
fuel?



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I expect that most stuff doesn't really care, but you will never know
until you try it. I've heard comments about some cheap inverters (steppy
waves) some laptop power supplies run hot, but not chased up the details.

The only apparatus that usually needs pure or as close to it as you can
get is stuff that is switching with mosfets(?) which need to sense the
zero crossing.

 
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Re: Generators and switch mode power supplies



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**Doesn't matter. A standby generator will deliver a 50Hz sine wave. It is a
mechanical device, comprising a petrol or diesel motor, linked to an
alternator. Inverters are for use with battery storage systems (VERY
expensive) Make certain you do the following:

* Ensure your generator can cope with fridges and the like. Fridges and
other motorised devices have huge switch-on demands and can cause generator
output to fall dramatically, thus risking damage to the motor (load).
* Do not even THINK about a large air con with anything but a very large
generator, UNLESS you are using an 'inverter' type air con. These have a
'soft start' and are suitable for use with most generators.
* Get a Diesel or a 4 stroke type.
* Buy one which has a lot more capacity than you think you'll need.


--
Trevor Wilson
www.rageaudio.com.au



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