# watts to amps



## chrisgreen (Jan 13, 2008)

copy and paste from another forum.
might be usefull to somebody?
if its been done before ,mods please delete.


The results are based on a uk supply rated at 230 volts 

60 Watts = 0.26 Amp

100 Watts = 0.43 Amp

200 Watts = 0.87 Amp

300 Watts = 1.30 Amp

400 Watts = 1.74 Amp

500 Watts = 2.17 Amp

600 Watts = 2.61 Amp

700 Watts = 3.04 Amp

800 Watts = 3.48 Amp

900 Watts = 3.91 Amp

1000 Watts = 4.35 Amp
1100 Watts = 4.78 Amp

1200 Watts = 5.22 Amp

1300 Watts = 5.65 Amp

1400 Watts = 6.09 Amp

1500 Watts = 6.52 Amp

1600 Watts = 6.96 Amp

1700 Watts = 7.39 Amp

1800 Watts = 7.83 Amp

1900 Watts = 8.26 Amp

2000 Watts = 8.70 Amp

2100 Watts = 9.13 Amp

2200 Watts = 9.57 Amp
2300 Watts = 10.00 Amp

2400 Watts = 10.43 Amp

2500 Watts = 10.87 Amp

2600 Watts = 11.30 Amp

2700 Watts = 11.74 Amp

2800 Watts = 12.17Amp

2900 Watts = 12.61 Amp

3000 Watts = 13.04 Amp

3100 Watts = 13.48 Amp

3200 Watts = 13.91 Amp

3300 Watts = 14.35 Amp

3400 Watts = 14.78 Amp

3500 Watts = 15.22Amp
3600 Watts = 15.65 Amp


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## DABurleigh (May 9, 2005)

I'm sure it will be helpful to some, thanks, though I hope it doesn't start a trend. I don't think I could stomach the 12-times table being listed.

Dave


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## DJP (May 9, 2005)

Simpler way is to divide watts by volts

e.g. 1000w divided by 230v gives 4.35amps as per ypur chart

Still a useful chart for those without a calculator.

Dennis


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## some-where-in-oxford (Apr 18, 2006)

I was taught to draw a triangle with line across centre, with watts, amp and volts in each corner of the triangle, trouble is I can never remember what goes where.

The way I remember is that a 1 HP motor is about 750 watts and draws about 3 amps. Running on 240 volts.

750 divided by 240 volts is about 3 amps. Watts/volts = Amps

240 x 3 amps is watts. Volts x Amps is Watts.

Leaving Watts/Amps is volts.


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## chrisjrv (May 7, 2007)

I'm with Dave on this, :roll: :roll:


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## pippin (Nov 15, 2007)

What about VA?

Or is that: Watt about Volt Amps?


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## some-where-in-oxford (Apr 18, 2006)

pippin said:


> What about VA?
> 
> Or is that: Watt about Volt Amps?


This is AC circuits not DC circuits????

Correct me is I am wrong.


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## sallytrafic (Jan 17, 2006)

Thats what I like to see an easy way of remembering 

I remember roughly how big a Newton is by thinking 4 small apples (cox's for preference) weigh about a lb. So a Newton is about the downwards force that one of those apples exerts.

For the pedants I know G is actually 9.81 and a lb is 454g


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## some-where-in-oxford (Apr 18, 2006)

sallytrafic said:


> Thats what I like to see an easy way of remembering
> 
> I remember roughly how big a Newton is by thinking 4 small apples (cox's for preference) weigh about a lb. So a Newton is about the downwards force that one of those apples exerts.
> 
> For the pedants I know G is actually 9.81 and a lb is 454g


Since we are going a bit off topic, can I go a bit further with something I picked up years ago.

I remember being told by the science teacher at school that the longest straw you could suck up your drink with was around 13 foot. Something to do with overcoming gravitational force? He never went on to say how he knew this?

Any idea?


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## DABurleigh (May 9, 2005)

Gravitational force only indirectly. The preferred explanation to students would be air pressure.

If you are comfortable with the concept of mm of Hg, just thin it down a bit 

Dave


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## some-where-in-oxford (Apr 18, 2006)

DABurleigh said:


> Gravitational force only indirectly. The preferred explanation to students would be air pressure.
> 
> If you are comfortable with the concept of mm of Hg, just thin it down a bit
> 
> Dave


Now you are loosing me. Are we talking about the affect atmospheric pressure on the surface of the liquid? Or am I way out now?


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## DABurleigh (May 9, 2005)

With apologies to chrisgreen for continuing the off topic to answer, read the section on atmospheric pressure based on height of water in:
http://en.wikipedia.org/wiki/Atmospheric_pressure

Effectively sucking approximates the vacuum at the top of a barometer.

Dave


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## sallytrafic (Jan 17, 2006)

some-where-in-oxford said:


> DABurleigh said:
> 
> 
> > Gravitational force only indirectly. The preferred explanation to students would be air pressure.
> ...


As Dave is offline I will answer.

Yes what forces the liquid up the straw is not the partial vacuum that you create by sucking but the force exerted by the atmosphere on the free liquid surface. If you could suck a perfect vacuum, for water it would be more like 13 meters high not 13 feet.

edit Dave beat me to it perhaps he lurks on line and convinces MHF that he's not here


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## eddievanbitz (May 1, 2005)

I thought that Boyles law was how much beer you could compress in a bucket before drinking it? 8O


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## Zebedee (Oct 3, 2007)

eddievanbitz said:


> I thought that Boyles law was how much beer you could compress in a bucket before drinking it? 8O


Nah. It's how much choccy you might have got through if there had been any in the machine! :lol: :lol: :lol: :lol:


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## Boff (May 10, 2005)

sallytrafic said:


> If you could suck a perfect vacuum, for water it would be more like 13 meters high not 13 feet.


Perhaps the original statement was "30 feet" instead of "13 feet"?

Because that would be pretty much correct for water...

Best Regards,
Gerhard


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## DABurleigh (May 9, 2005)

I envy you your lungs, Gerhard ;-)

I propose an MHF rally competition. It might be 13 feet in practice! 

Dave


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## sallytrafic (Jan 17, 2006)

Its amazing what you stumble upon. In an attempt to put a number on how far you can suck water with your lungs I came across the reason why we periodically sigh >here<

Sigh


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## eddied (May 9, 2005)

Buon giorno, wonderful stuff, all this collective knowledge. As per my signature, I well know why I periodically sigh. Trying to devise a formula that will satisfactorilly divide 1000 Euro x 30 days living!
Sigh.
saluti, eddied


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## Boff (May 10, 2005)

DABurleigh said:


> I envy you your lungs, Gerhard ;-)


Only a matter of the straw's diameter... :wink:

If this is not more than 0.7 millimetres, then I will do it. 

Best Regards,
Gerhard


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## sallytrafic (Jan 17, 2006)

Boff said:


> DABurleigh said:
> 
> 
> > I envy you your lungs, Gerhard ;-)
> ...


Boff as you well know that would be cheating


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## 96558 (Oct 21, 2005)

*Re: watts and amps*

If I may add a point on this subject, of course the calculations only apply IF the mains voltage is at 230. There are variations in G.B, but from my recent experience in France most sites are below 230 volt and many not even reaching 200 volt. In this case, for example the 6 amp supply you have paid a high price for would not do what you expect. Do you check the mains voltage on hook up? If you don't you will not know the watts available.


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## Boff (May 10, 2005)

sallytrafic said:


> Boff as you well know that would be cheating


 :twisted:  :wink:

SCNR,
Gerhard


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## safariboy (May 1, 2005)

Someone asked what is VA. The term only is used for A.C. and is to do with something called power factor which is unlikely to be a problem for us.
Volts times amps may not be quite Watts in some A.C. circuits. So Watts measures the actual power and VA is volts times amps. In real motorhomes the difference does not matter, but in the lab I can set up a demonstration where there is a value of VA but watts are zero.
If anyone wants to P.M. for a clearer - but much longer - explanation they are welcome to do so but I don't see many takers!


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## DABurleigh (May 9, 2005)

Now as to straws, I reckon it is sucking power to get the nearest to a vacuum that matters, not lung capacity. In such a competition, practised tongue technique can yield multiple exhales while plugging the straw with the tongue 

Dave


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