Generators and switch mode power supplies

[Sylvia Else]

Given the parlous state of Australia's power systems, I've been
considering buying a standby generator. One marketing point of some of
the inverter bases models is their suitability for 'sensitive
electronics' with computers given as an example. This appears to be
based on the fact that they'll provide a consistent sinewave output.

But given that computers invariably use switch-mode power supplies, are
they actually going to care what waveform they see - from square wave
thru 'modified sinewave' thru pure sinewave?

Sylvia.

 

[Bob Parker]

On 4/02/2009 22:09 Sylvia Else wrote:

Given the parlous state of Australia's power systems, I've been
considering buying a standby generator. One marketing point of some of
the inverter bases models is their suitability for 'sensitive
electronics' with computers given as an example. This appears to be
based on the fact that they'll provide a consistent sinewave output.

But given that computers invariably use switch-mode power supplies, are
they actually going to care what waveform they see - from square wave
thru 'modified sinewave' thru pure sinewave?

Sylvia.

I haven't experienced any power interruptions here in Sydney for
many months so the supply's not exactly parlous where I am.
My cheap UPS doesn't output a clean sine wave but the PC and
monitor (switching supplies), answering machine and modem power supplies
(50Hz transformer plugpacks) all work quite happily from it when it
kicks in.
I doubt that exact waveform makes much difference to most power
supplies, especially switching supplies. Just my 2c worth...

 

[Phil Allison]

"Sylvia Else = Sillier than Anyone Else "


** Sylvia Else = a Pommy bitch = usenet's most notorious TROLL.

Ever seen her pic ?

http://www.onlineopinion.com.au/author.asp?id=3937

And that's an old one !!!!!!!!!!!!!!!!!!

Know about her being a crazy nudist who tried to get a nudist political
party going in NSW ?

NLP = Naturist Lifestyle Party ( Inc) .

Sylvia was the secretary of the group.

Wot a hooooot !!

Given the parlous state of Australia's power systems,

** Massive fallacy.

Sylvia lives in Frenchs Forrest in Sydney.

Dare dispute this Sylvia and I will post you EXACT address

- bitch brain.

I've been considering buying a standby generator.

** The fuckwit pommy bitch has no idea what the term means.

One marketing point of some of the inverter bases models

** An " inverter " is a NOT a generator

YOU RIDICULOUS BITCH !!!!

But given that computers invariably use switch-mode power supplies, are
they actually going to care what waveform they see - from square wave thru
'modified sinewave' thru pure sinewave?

** Computers all have monitors and most have sound cards and video cards.

All of which may well be negatively affected in various ways by being
powered by a POS fucking "modified square wave " inverter.

Go by one and FUCKING FIND OUT !!!!!!!

You VILE DUMB BITCH .




...... Phil

 

[terryc]

On Wed, 04 Feb 2009 22:09:58 +1100, Sylvia Else wrote:

Given the parlous state of Australia's power systems, I've been
considering buying a standby generator.

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

But given that computers invariably use switch-mode power supplies, are
they actually going to care what waveform they see - from square wave
thru 'modified sinewave' thru pure sinewave?

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.


> Sylvia.

 

[a t e c 7 7]

Bob Parker wrote:

On 4/02/2009 22:09 Sylvia Else wrote:
you would do well to ignore this poster , stupid is and silly
troll.... asyou will find out .

 

[Bob Parker]

On 5/02/2009 00:20 a t e c 7 7 wrote:

Bob Parker wrote:
On 4/02/2009 22:09 Sylvia Else wrote:
you would do well to ignore this poster , stupid is and silly
troll.... asyou will find out .

Huh? I'm not a troll. At least I don't think I am...

 

[a t e c 7 7]

Bob Parker wrote:

On 5/02/2009 00:20 a t e c 7 7 wrote:
Bob Parker wrote:
On 4/02/2009 22:09 Sylvia Else wrote:
you would do well to ignore this poster , stupid is and silly
troll.... asyou will find out .

Huh? I'm not a troll. At least I don't think I am...


saliva is though

 

[Sylvia Else]

Bob Parker wrote:

On 4/02/2009 22:09 Sylvia Else wrote:
Given the parlous state of Australia's power systems, I've been
considering buying a standby generator. One marketing point of some of
the inverter bases models is their suitability for 'sensitive
electronics' with computers given as an example. This appears to be
based on the fact that they'll provide a consistent sinewave output.

But given that computers invariably use switch-mode power supplies,
are they actually going to care what waveform they see - from square
wave thru 'modified sinewave' thru pure sinewave?

Sylvia.


I haven't experienced any power interruptions here in Sydney for
many months so the supply's not exactly parlous where I am.

NSW is in a better condition. The other states show predicted reserve
shortfalls in the coming months.

http://www.nemmco.com.au/data/MToutlook.htm

In some ways, though, reserve shortfalls are not such a huge concern,
because the resulting blackouts get shared around, with no individual
group of cumstomers subject to extened periods without power.

Of greater concern are overloaded transformers. If they fail it can take
quite a long time for supplies to be restored. In periods of hot weather
such events have been known.

Sylvia.

 

[Trevor Wilson]

"Sylvia Else" <sylvia@not.at.this.address> wrote in message
news:gmbt1u$1rd$1@aioe.org...

Given the parlous state of Australia's power systems, I've been
considering buying a standby generator. One marketing point of some of the
inverter bases models is their suitability for 'sensitive electronics'
with computers given as an example. This appears to be based on the fact
that they'll provide a consistent sinewave output.

But given that computers invariably use switch-mode power supplies, are
they actually going to care what waveform they see - from square wave thru
'modified sinewave' thru pure sinewave?

**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

 

[terryc]

On Wed, 04 Feb 2009 23:21:41 +1100, Bob Parker wrote:

I haven't experienced any power interruptions here in Sydney for
many months so the supply's not exactly parlous where I am.

Who is your supplier?
I'm on Integral and you expect a few hours once a month. I suspect
they are butchering the wrong trees.

 

[terryc]

On Thu, 05 Feb 2009 11:56:44 +1100, Trevor Wilson wrote:

* 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).

double the rating?

* 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.

And have a place out side that gets a good breeze flowing away from the
house to run it. The USA provides a continual stream of stories of people
who ran the generator inside and experienced why you do not do this.

 

[David L. Jones]

On Feb 5, 10:41 am, Sylvia Else <syl...@not.at.this.address> wrote:

Bob Parker wrote:
On 4/02/2009 22:09 Sylvia Else wrote:
Given the parlous state of Australia's power systems, I've been
considering buying a standby generator. One marketing point of some of
the inverter bases models is their suitability for 'sensitive
electronics' with computers given as an example. This appears to be
based on the fact that they'll provide a consistent sinewave output.

But given that computers invariably use switch-mode power supplies,
are they actually going to care what waveform they see - from square
wave thru 'modified sinewave' thru pure sinewave?

Sylvia.

I haven't experienced any power interruptions here in Sydney for
many months so the supply's not exactly parlous where I am.

NSW is in a better condition. The other states show predicted reserve
shortfalls in the coming months.

http://www.nemmco.com.au/data/MToutlook.htm

In some ways, though, reserve shortfalls are not such a huge concern,
because the resulting blackouts get shared around, with no individual
group of cumstomers subject to extened periods without power.

Of greater concern are overloaded transformers. If they fail it can take
quite a long time for supplies to be restored. In periods of hot weather
such events have been known.

So what's the big deal if it *does* happen?
Not the end of the world.
Go for a walk, go shopping, go visit a friend, read a book by torch or
candle light, and countless other things you can do without mains
power.

The other week I was stuck in a lift (in Frenchs Forest of all places)
for more than an hour during a blackout, it was actually quite fun.

You'll survive, really, no need for a generator when you live in
Frenchs Forest.

Dave.

 

[Mr.T]

"Sylvia Else" <sylvia@not.at.this.address> wrote in message
news:gmd938$6eb$1@aioe.org...

In some ways, though, reserve shortfalls are not such a huge concern,
because the resulting blackouts get shared around, with no individual
group of cumstomers subject to extened periods without power.

Great consolation for those tens of thousands without power for their
fridges and freezers during the recent heatwave down south.

Of greater concern are overloaded transformers. If they fail it can take
quite a long time for supplies to be restored. In periods of hot weather
such events have been known.

Sure have, and the resulting fires in some cases burnt homes or factories to
the ground!

Still profit is more important than minor supply and maintenance issues.

MrT.

 

[Mr.T]

"David L. Jones" <altzone@gmail.com> wrote in message
news:201ff386-0902-428d-8252-390a0df30351@k1g2000prb.googlegroups.com...

Of greater concern are overloaded transformers.

So what's the big deal if it *does* happen?
Not the end of the world.

It was pretty close for some people in South Australia. Their burnt out
homes and factories anyway!

MrT.

 

[Mr.T]

"terryc" <newssevenspam-spam@woa.com.au> wrote in message
news:498a441d$0$96977$c30e37c6@pit-reader.telstra.net...

And have a place out side that gets a good breeze flowing away from the
house to run it. The USA provides a continual stream of stories of people
who ran the generator inside and experienced why you do not do this.

I attended the funeral of someone who also discovered it the hard way. You'd
think the number of people using a car exhaust to commit suicide might give
some clue though.

MrT.

 

[Trevor Wilson]

"terryc" <newssevenspam-spam@woa.com.au> wrote in message
news:498a441d$0$96977$c30e37c6@pit-reader.telstra.net...

On Thu, 05 Feb 2009 11:56:44 +1100, Trevor Wilson wrote:

* 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).

double the rating?

**That's the figure I've been told. However, I suspect it has a lot to do
with the manufacturer. Quality manufactured products probably have short
term overload capacity built in. Those cheap, Chinese generators from
Bunnings probably barely meet their own specs.

* 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.

And have a place out side that gets a good breeze flowing away from the
house to run it. The USA provides a continual stream of stories of people
who ran the generator inside and experienced why you do not do this.

**Indeed. It's amazing how stupid some people can be. I'm clearing 30-odd cu
Metres of soil and rock from under my house. I'm doing it by hand, or with
electrically powered tools only. It's bloody hard yakka. A few smartarses
have suggested I should hire a DingoT and get the job done in a few days.
Sheesh! There's no air flow under there and almost no viable method to push
much air through either. I'd be lucky to last 30 mins.


--
Trevor Wilson
www.rageaudio.com.au

 

[Mr.T]

"Trevor Wilson" <trevor@_SPAMBLOCK_rageaudio.com.au> wrote in message
news:6uv0e6Fhffh0U1@mid.individual.net...

**Indeed. It's amazing how stupid some people can be. I'm clearing 30-odd
cu
Metres of soil and rock from under my house. I'm doing it by hand, or with
electrically powered tools only. It's bloody hard yakka. A few smartarses
have suggested I should hire a DingoT and get the job done in a few days.
Sheesh! There's no air flow under there and almost no viable method to
push
much air through either. I'd be lucky to last 30 mins.

You could use an oxygen tank, or an externally pumped air supply if you
thought it worth it. I'm guessing you don't.

MrT.

 

[Trevor Wilson]

"Mr.T" <MrT@home> wrote in message
news:498a4cb8$0$32001$afc38c87@news.optusnet.com.au...

"Trevor Wilson" <trevor@_SPAMBLOCK_rageaudio.com.au> wrote in message
news:6uv0e6Fhffh0U1@mid.individual.net...
**Indeed. It's amazing how stupid some people can be. I'm clearing 30-odd
cu
Metres of soil and rock from under my house. I'm doing it by hand, or
with
electrically powered tools only. It's bloody hard yakka. A few smartarses
have suggested I should hire a DingoT and get the job done in a few days.
Sheesh! There's no air flow under there and almost no viable method to
push
much air through either. I'd be lucky to last 30 mins.

You could use an oxygen tank, or an externally pumped air supply if you
thought it worth it. I'm guessing you don't.

**You guessed right. Logistics beat me everytime I thought it through.
* I'd need to remove two door frames (not such a huge deal, but
inconvenient). There's around 2cm clearance for a DingoT at present. I'm
told that is sufficient to guarantee damage. Then there's the (lack of)
security thing, whilst the job is progressing.
* I'd need to organise bins to cart away the 50cu Metres (as you probably
know, the stuff 'fluffs' up, when you dig it) of stuff. I can only manage 2
cu Metre bins at any one time.
* Based on the above, I'd need a DingoT for a great deal longer than the
optimum period of 2 days. I'd reckon on at least a month. Too expensive.
* I'm not in a desperate hurry. If I was, I'd pay some guys to do it.

I'll keep doing it by hand. It's good exercise.


--
Trevor Wilson
www.rageaudio.com.au

 

[terryc]

On Thu, 05 Feb 2009 13:15:12 +1100, Trevor Wilson wrote:

**Indeed. It's amazing how stupid some people can be. I'm clearing 30-odd cu
Metres of soil and rock from under my house. I'm doing it by hand, or with
electrically powered tools only. It's bloody hard yakka.

Been there done that when we were younger.
If it requires drainage, make sure that the drainage hose is below the
concrete slab.

A few
smartarses have suggested I should hire a DingoT and get the job done in
a few days. Sheesh! There's no air flow under there and almost no viable
method to push much air through either. I'd be lucky to last 30 mins.

You could probably hire a mine ventilator tube as well. The real problem
is when they ggraze the foundations.

 

[kreed]

On Feb 4, 9:09 pm, Sylvia Else <syl...@not.at.this.address> wrote:

Given the parlous state of Australia's power systems, I've been
considering buying a standby generator. One marketing point of some of
the inverter bases models is their suitability for 'sensitive
electronics' with computers given as an example. This appears to be
based on the fact that they'll provide a consistent sinewave output.

But given that computers invariably use switch-mode power supplies, are
they actually going to care what waveform they see - from square wave
thru 'modified sinewave' thru pure sinewave?

Sylvia.

Regarding "inverter" generators:

Honda (and possibly others) now offer generators with an inbuilt
sinewave "inverter" in
order to provide high quality power (presumably crystal locked to
50hz) for sensitive
equipment regardless of generator motor speed fluctuations etc.
This would also allow lower engine speeds at low load to save fuel,
without affecting the output frequency

http://mayberrys.com/honda/generator/html/invertgenerator.htm


Another advertised advantage of this system is the ability to link 2
of these
units together in parallel via a special cable (available from Honda)
in order to increase the total output capacity.
This would probably have extra wire(s) to ensure the inverters outputs
are synchronised, their output voltages as close as possible to each
other to keep the load balanced between the 2 inverters/generators ?

http://mayberrys.com/parallel/parallel.htm

this provides 30a @ 120v (equivalent to a 15A 240v socket.) (note -
this is for US use only, there would be an Australian version.)

The other advantage that this dual system MIGHT have is the ability
to keep critical equipment in the home (such as life support) running
in the home if one of the two generators fails, as long as the total
load is sufficient for one unit.
(NOTE: I don't want to go round giving advice on this, or saying its
100% foolproof, or legal, or safe in case Im wrong and someone is
hurt or dies, please seek expert advice from the supplier or
manufacturer or other expert before using or relying on this or any
other method of powering life support)

For most people, I think this sort of unit would be an good choice for
occasional temporary emergency home use of lighting, computers, phone
charges etc etc and you can be sure it will run ANY sensitive
equipment just as well as off the mains. Gas rings would be more
efficient for cooking, boiling water etc.


Trevor's comments on selecting a generator should be noted also.
regarding large loads, fridges air cons etc,


2 problems I can recall with use of non-mains power are :

Note there was a letter from a reader in silicon chip recently
regarding use of a generator powering a battery charger on a boat, the
battery charger wouldn't start at all with one particular generator
(probably because of low quality or noisy power) and worked perfectly
with another.

Another problem I have had personally is with my Dewalt cordless drill
I bought in the 1990s when they first came out.
It charged perfectly on the mains, but wouldnt charge on a modified
square wave inverter (note: true sine wave inverters/generators
wouldn't give this problem) we used in the work van. IT turned out to
be a "series capacitor" type power supply (transformerless).
Fortunately it charged pretty fast compared to the older cordless
drills, and armed with a spare battery we just charged it off the
mains at places where we were doing jobs.

These are examples of where a TRUE SINEWAVE inverter generator would
be of benefit.


I dont think a PC would need this and would work happily off a square
wave or modified square wave inverter (this is what most UPS provide.