Rule of Tim: Making a cheap Genny safe for a Puter.

Right, thought I'd exercise my right to use the Rule of Tim.

I'm about to invest a HUGE amount of £80 in a cheap gererator for this
weekend (National 4x4) , now then I know nothing about them but do have a
recollection that there may be issues running a Laptop and a Projector from
said el-cheapo generator. Is there any way to make the power supply safe
without shelling out another £600?

Mrs D has suggested I get a genny as a backup for the caravan, using in the
above prescribed manner would just be a bonus so it's not t' end of the
world if It's unfeasible.


Lee D

Lee_D came up with the following;:
> Right, thought I'd exercise my right to use the Rule of Tim.
>
> I'm about to invest a HUGE amount of £80 in a cheap gererator for this
> weekend (National 4x4) , now then I know nothing about them but do have a
> recollection that there may be issues running a Laptop and a Projector
> from said el-cheapo generator. Is there any way to make the power supply
> safe without shelling out another £600?
>
> Mrs D has suggested I get a genny as a backup for the caravan, using in
> the above prescribed manner would just be a bonus so it's not t' end of
> the world if It's unfeasible.

Run the electrics through a UPS ... Uninterruptible Power Supply, which is
in effect a big battery, which also has the effect of smoothing the power
flow and providing a 'clean' supply.

Maplins do one at about £30 ish that should work well enough.

--
Paul ...
(8(|) Homer Rules ..... Doh !!!

In message <[email protected]>
"Lee_D" <[email protected]> wrote:

> Right, thought I'd exercise my right to use the Rule of Tim.
>
> I'm about to invest a HUGE amount of £80 in a cheap gererator for this
> weekend (National 4x4) , now then I know nothing about them but do have a
> recollection that there may be issues running a Laptop and a Projector from
> said el-cheapo generator. Is there any way to make the power supply safe
> without shelling out another £600?
>
> Mrs D has suggested I get a genny as a backup for the caravan, using in the
> above prescribed manner would just be a bonus so it's not t' end of the
> world if It's unfeasible.
>
>
> Lee D
>
>
>
I run our computer at shows straight off a cheapo generator - no problems.

Richard

--
www.beamends-lrspares.co.uk [email protected]
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
Boycott the Yorkshire Dales - No Play, No Pay

On Fri, 23 Sep 2005 09:45:04 +0100, "Lee_D"
<[email protected]> wrote:

>Right, thought I'd exercise my right to use the Rule of Tim.
>
>I'm about to invest a HUGE amount of £80 in a cheap gererator for this
>weekend (National 4x4) , now then I know nothing about them but do have a
>recollection that there may be issues running a Laptop and a Projector from
>said el-cheapo generator. Is there any way to make the power supply safe
>without shelling out another £600?
>
>Mrs D has suggested I get a genny as a backup for the caravan, using in the
>above prescribed manner would just be a bonus so it's not t' end of the
>world if It's unfeasible.
>
>
>Lee D
>
>

I'd expect a decent laptop PSU to isolate variations in the input and
create a decent DC output. The projector may be a different kettle of
fish. As suggested elsewhere, use a cheap UPS, or possibly a
surge-protector 4-way adaptor as an even cheaper, less good option.
Check the draw of the projector and that it is within the limits of
the generator and the UPS, especially when first powered up.




--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70

"Tim Hobbs" <[email protected]> wrote in message
news:[email protected]...

> I'd expect a decent laptop PSU to isolate variations in the input and
> create a decent DC output. The projector may be a different kettle of
> fish. As suggested elsewhere, use a cheap UPS, or possibly a
> surge-protector 4-way adaptor as an even cheaper, less good option.
> Check the draw of the projector and that it is within the limits of
> the generator and the UPS, especially when first powered up.


Cheers , I'll check the current drawn first, seems maplins do a UPS at
£29.00 so once I'm sure I may commit then.

How does one work out the initial start up loading of the Projector, is
there a formular or is it another gadet?

Lee D

On Fri, 23 Sep 2005 13:11:59 +0100, "Lee_D"
<[email protected]> wrote:

>"Tim Hobbs" <[email protected]> wrote in message
>news:[email protected]...
>
>> I'd expect a decent laptop PSU to isolate variations in the input and
>> create a decent DC output. The projector may be a different kettle of
>> fish. As suggested elsewhere, use a cheap UPS, or possibly a
>> surge-protector 4-way adaptor as an even cheaper, less good option.
>> Check the draw of the projector and that it is within the limits of
>> the generator and the UPS, especially when first powered up.
>
>
>Cheers , I'll check the current drawn first, seems maplins do a UPS at
>£29.00 so once I'm sure I may commit then.
>
>How does one work out the initial start up loading of the Projector, is
>there a formular or is it another gadet?
>
>Lee D
>

If it's notable then the book ought to tell you. I don't know much
about it, but the lamp is an expensive consumable. It will draw
different current when flat cold until it gets hot, with a
corresponding effect on supply voltage.


--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70

On Fri, 23 Sep 2005 14:24:12 +0100, Tim Hobbs <[email protected]> wrote:

>If it's notable then the book ought to tell you. I don't know much
>about it, but the lamp is an expensive consumable. It will draw
>different current when flat cold until it gets hot, with a
>corresponding effect on supply voltage.

Projector lamps also need to be allowed to cool down properly (yes,
that was an expensive show...)

In order to answer the question of power startup, yes, lots actually,
but newer projectors will softstart. Never, ever run a video
projector off a dirty generator, ever.

To measure what it uses, get a plug in power and energy monitor;

http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&doy=23m9D

This is a really handy and somewhat scary tool that you should use on
ALL of your home electronics and domestic appliances. I'll even
calculate how much energy you've used over a certain period of time.

Best way to help you reduce your energy consumption.


--
"We have gone from a world of concentrated knowledge and wisdom to one
of distributed ignorance. And we know and understand less while being
increasingly capable." Prof. Peter Cochrane, formerly of BT Labs
In memory of Brian {Hamilton Kelly} who logged off 15th September 2005

On Friday, in article <[email protected]>
[email protected] "Paul - xxx" wrote:

> Lee_D came up with the following;:
> > Right, thought I'd exercise my right to use the Rule of Tim.
> >
> > I'm about to invest a HUGE amount of £80 in a cheap gererator for this
> > weekend (National 4x4) , now then I know nothing about them but do have a
> > recollection that there may be issues running a Laptop and a Projector
> > from said el-cheapo generator. Is there any way to make the power supply
> > safe without shelling out another £600?
> >
> > Mrs D has suggested I get a genny as a backup for the caravan, using in
> > the above prescribed manner would just be a bonus so it's not t' end of
> > the world if It's unfeasible.
>
> Run the electrics through a UPS ... Uninterruptible Power Supply, which is
> in effect a big battery, which also has the effect of smoothing the power
> flow and providing a 'clean' supply.
>
> Maplins do one at about £30 ish that should work well enough.

Trouble is, there's two very different types of UPS.

One connects mains direct to output until it fails, when it switches on
the inverter and draws from the battery.

The other has no AC connection between input and output. The inverter
runs full-time, and the mains-to-DC is trickle-charging the battery.

The second type is a really good noise filter -- the battery acts as a
huge smoothing capacitor on the DC supply to the inverter.

But switched-mode PSUs rectify to DC as the first stage, and then run
the transformers at mugh higher frequencies. so they're pretty noise-
tolerant. I reckon it's the projector you have to be wary of.

--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."

On Fri, 23 Sep 2005 14:53:08 +0100, Mother wrote:

> Projector lamps also need to be allowed to cool down properly (yes,
> that was an expensive show...)
>
> In order to answer the question of power startup, yes, lots
> actually, but newer projectors will softstart. Never, ever run a
> video projector off a dirty generator, ever.

I'd be very wary of the ordinary small and cheap non-AVR or
non-invertor (smart throttle) type gennys. At the £80 price point the
OP is looking at the small 600 to 800W cheap and only vaguely
regulated jobbies. Alright for a light bulb or small telly but may
well struggle to start a fridge or freezer...

I'd expect a modern projector to be using a low voltage bulb not one
directly connected to the mains. These high power low voltage bulbs
are expensive (three figures before the decimal point) and rather
finickity about their supply. I'd expect the PSU to provide enough
isloation from the supply but how well that PSU would reposnd to a
genny bouncing up and down from 150 to 300v is another matter...

Putting a UPS in circuit only *might* even out supply variations it
depends on the design and function of the UPS. I suspect the £30
Maplins jobbie will just pass the input to the output with perhaps a
bit of filtering when the input it present and produce something
quickly when the mains input fails. My APC SmartUPS basically does
that but can boost or reduce the "passed through" power as well
without fireing up the invertor section. Judging by the clunks it
makes in switching I suspect that is acheived by changing tappings on
an (auto?) transformer.

> To measure what it uses, get a plug in power and energy monitor;
>
> http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&doy=23m9D
>
> This is a really handy and somewhat scary tool that you should use
> on ALL of your home electronics and domestic appliances.

But can be wildly inaccurate on devices with switched mode PSUs. A
useful tool but you need to know it's limitations.

> In memory of Brian {Hamilton Kelly} who logged off 15th September
> 2005

What were the circumstances of his log off? I've corresponded with
Brian in the past, normally about ISDN, iPABXs and OS/2.

--
Cheers [email protected]
Dave. pam is missing e-mail

On Fri, 23 Sep 2005 16:07:55 +0100 (BST), "Dave Liquorice"
<[email protected]> wrote:

>I'd expect a modern projector to be using a low voltage bulb not one
>directly connected to the mains. These high power low voltage bulbs
>are expensive (three figures before the decimal point) and rather


Yeah, and having blown one or two in the past, I felt it worthwhile
pointing this out to Lee!


>> To measure what it uses, get a plug in power and energy monitor;
>>
>> http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&doy=23m9D
>>
>> This is a really handy and somewhat scary tool that you should use
>> on ALL of your home electronics and domestic appliances.
>
>But can be wildly inaccurate on devices with switched mode PSUs. A
>useful tool but you need to know it's limitations.


It's handy to see what's being drawn from the socket, and scary to see
how much (as an excample) our coffee maker costs us in the office!


>> In memory of Brian {Hamilton Kelly} who logged off 15th September
>> 2005
>
>What were the circumstances of his log off? I've corresponded with
>Brian in the past, normally about ISDN, iPABXs and OS/2.


I only learnt from Pedt in unnc, but the original posting in
demon.service was:

"I regret to announce that he died suddently from Acute Myeloid
Leukemia, which he was only recently diagnosed with, although he had
been ill for a while."

Shame. Brian had a lot of 'clue'.



--
"We have gone from a world of concentrated knowledge and wisdom to one
of distributed ignorance. And we know and understand less while being
increasingly capable." Prof. Peter Cochrane, formerly of BT Labs
In memory of Brian {Hamilton Kelly} who logged off 15th September 2005

David G. Bell wrote:
> On Friday, in article <[email protected]>
> [email protected] "Paul - xxx" wrote:
>
>
>>Lee_D came up with the following;:
>>
>>>Right, thought I'd exercise my right to use the Rule of Tim.
>>>
>>>I'm about to invest a HUGE amount of £80 in a cheap gererator for this
>>>weekend (National 4x4) , now then I know nothing about them but do have a
>>>recollection that there may be issues running a Laptop and a Projector
>>>from said el-cheapo generator. Is there any way to make the power supply
>>>safe without shelling out another £600?
>>>
>>>Mrs D has suggested I get a genny as a backup for the caravan, using in
>>>the above prescribed manner would just be a bonus so it's not t' end of
>>>the world if It's unfeasible.
>>
>>Run the electrics through a UPS ... Uninterruptible Power Supply, which is
>>in effect a big battery, which also has the effect of smoothing the power
>>flow and providing a 'clean' supply.
>>
>>Maplins do one at about £30 ish that should work well enough.
>
>
> Trouble is, there's two very different types of UPS.
>
SG: Strictly speaking there are three types of UPS, but who's counting?
Between the two you describe below (off-line and on-line respectively)
there is a half-way house, typically, called in-line.

At the cheap end of the market you can only get off-line units which
only switch on if the power fails completely or if there are major
sags/surges in the ac power. They are totally unsuitable for use with a
generator if you're expecting the UPS to do some smoothing ... cuz it
won't. For that you need at least an in-line unit at mucho more dosh :-(
and even then it won't compensate for frequency variations, which are
very common with small generators.

You can get some good info from > http://tinyurl.com/d45ez

<snipped>

--
Regards

Steve G

Lee_D wrote:
> "Tim Hobbs" <[email protected]> wrote in message
> news:[email protected]...
>
>
>>I'd expect a decent laptop PSU to isolate variations in the input and
>>create a decent DC output. The projector may be a different kettle of
>>fish. As suggested elsewhere, use a cheap UPS, or possibly a
>>surge-protector 4-way adaptor as an even cheaper, less good option.
>>Check the draw of the projector and that it is within the limits of
>>the generator and the UPS, especially when first powered up.
>
>
>
> Cheers , I'll check the current drawn first, seems maplins do a UPS at
> £29.00 so once I'm sure I may commit then.
>
> How does one work out the initial start up loading of the Projector, is
> there a formular or is it another gadet?
>
> Lee D
>
>
Lee, before buying an el-cheapo UPS take a look at http://tinyurl.com/d45ez

From memory, when I used to sell UPS, we used a rule of thumb that the
start-up current draw was 10 times the stable in-use current for just
about anything electronic.

--
Regards

Steve G

On Fri, 23 Sep 2005 17:13:10 +0100, Mother wrote:

> I only learnt from Pedt in unnc, but the original posting in
> demon.service was:
>
> "I regret to announce that he died suddently from Acute Myeloid
> Leukemia, which he was only recently diagnosed with, although he had
> been ill for a while."
>
> Shame. Brian had a lot of 'clue'.

Agreed, never physically met but was always helpful and knowledgable
on the net.

--
Cheers [email protected]
Dave. pam is missing e-mail

"Mother" <"@ {mother} @"@101fc.net> wrote in message
news:[email protected]...
> Yeah, and having blown one or two in the past, I felt it worthwhile
> pointing this out to Lee!

Mucho appreciated, I aborted any clever stuff until I'm suitably confident
that I'm not going to put something in to orbit.

:0)

Lee D