That's great, Andro, a good down to earth hardcore engineering
approach that produces useful and useable results .

But what I want to see is that the incessantly loudmouthed
NG physicists in here, the Einstein fanatics and Maxwellians
to come out and give OP ji40 a GENERAL step by step .
***equation sequence from Maxwell -> V,A,O, -> to A-turns.**

With Draper, one down, their silence is deafening...ahaha..
Isn't their a single physicist in this NG here who can do that?
Do you NG physicists & mathers have to rely on engineers
do do your job?
Come on dudes, get the finger out & show that you have cereballs.
ahahaha... ahahahanson

"Androcles" <Engineer@hogwarts.physics.co.uk> wrote in message
news:qEs_h.133321$Zb2.31182@fe2.news.blueyonder.co.uk...

"hanson" <hanson@quick.net> wrote in message
news:Xaq_h.6734$2V1.4553@trnddc08...

Paul "PD" <TheDraperFamily@gmail.com> wrote in message
news:1178216140.285165.237250@q75g2000hsh.googlegroups.com...

"Androcles" <Engin...@hogwarts.physics.co.uk> wrote:

"PD" <TheDraperFam...@gmail.com> wrote in

On May 3, 3:16 am, "Androcles" <Engin...@hogwarts.physics.co.uk>

"hanson" <han...@quick.net> w/i =

"Androcles" <Engin...@hogwarts.physics.co.uk> wrote in message
news:u39_h.91539$aB1.12260@fe3.news.blueyonder.co.uk...
This dude, premji40, wants to stuff 220V DC (not AC) into a block of
soft iron no bigger than a model train motor and play electromagnets.
I have to wonder if he'd realize what the kick would be from the back
EMF when switching OFF.
His mother would crucify me if I gave him any encouragement. Sheesh,
I did that when I was a kid and popped fuses, getting my knuckles =

for it. Let him play with 9V batteries.

[hanson to Andro]
.... ahahaha... but you are letting all those highfaluting NG =

student-know-it-alls off the hook, the ones who are always singing
about Maxwell's equations and are loudmouthing & grandstanding
about the curl... Let's see whether they bite and perform... or =

they are just buzz-wording but can't perform.... ahahaha....

[Andro]
Divergence is at right angles to the surface of a sphere, so it's =

down
from your feet to the centre of the Earth and stops dead, or straight =

and
goes on forever. Gravity is divergent.

[Paul to Andro]

:>) Divergence is a scalar, Androcles.

[Andro]

Divergence is the defined direction of a force, not the magnitude =

force.
Therefore it is not a scalar, you don't know what you are babbling
about.
Now *****, I was chatting with hahahahanson, not you, and =

just
loudmouthed and buzz-worded as hahahahanson predicted you would.
Go brush up at
http://www.androcles01.pwp.blueyonder.co.uk/Vector/Vector.htm

[Paul to Andro]

Hmm.... nothing about divergence on your own web page above.
Perhaps you meant one of these?
http://mathworld.wolfram.com/Divergence.html
http://tutorial.math.lamar.edu/AllBrowsers/2415/CurlDivergence.asp
http://planetmath.org/encyclopedia/DivergenceTheorem.html
http://www.math.umn.edu/~nykamp/m2374/readings/divcurl/
http://www.everything2.com/index.pl?node=3Dvector%20calculus
http://www.math.tamu.edu/~fnarc/m311/f03/m311_r3.html
http://hyperphysics.phy-astr.gsu.edu/hbase/diverg.html
http://www.mathpages.com/home/kmath330/kmath330.htm
But why would you need to read up, since you have a degree in
mathematics...? Ah, the scourge of rust -- terrible, really. Try a
wire brush.
Since hahahahahahanson seems to thrive on junk food, I provide
this as a service to verify that what you are offering is indeed =

PD

[hanson]
ahahaha.. Paul, you fat old slob, never mind my diet nor my thriving.
But I do respect that you took the hook for the "highfaluting NG
teacher- & student-know-it-alls", Now instead of you "babbling", =

do SHINE and produce the formula/equation sequence starting with
Maxwell's equations and help the OP in his request for

ji40 aka "premji40" <paramjit48@gmail.com> wrote in message
news:1178114837.110602.116330@p77g2000hsh.googlegroups.com...

If I know the volts, ampare and ohms than how can calculate
ampereturns. For example a Electromagnet have 220 volt dc ,
13.5Ampare and 13.7 ohms and I want to know ampare turns
can it possible to know ampere turns of this electromagnet.
********** Help me to know the formula ************

[hanson]
Have at it, Paul, be a good teacher, Show ji40 the formula!...
without weaseling. Don't tell ji40 what's wrong etc.
Just post the equation sequence: Maxwell -> V,A,O, -> A-turns.
Take care.
hanson

[Andro]
Since the dork doesn't know the difference between a scalar and
a scalar field, it should be interesting to see that. I hope ji40 =

no notice.
=20
For your benefit alone, hanson, there are 80 turns of 30 gauge copper =

per segment in the armature of a 1960's Black and Decker drill =

run intermittently (not continuously) from a British 230V 50 Hz =

That's from memory, I've rewound dozens of them, they burn up easily.
=20
If you want it to run at 110 V 60Hz US supply, a rough guide is to =

the cross sectional area and halve the turns for the same ampere =

It will still only be intermittently rated.
=20
Watts =3D Volts * Amps, so half voltage needs double amps for the same =

Such a drill is about 1/4-1/3 horsepower, or about 200 watts. Call it =

amp at
230 V, 2 amps at 110 V.
=20
Double amps means double cross sectional area of the wire but now the
current
is doubled, you only need 40 turns for the same ampere turns. Now the =

still completely fills the slot.
http://www.ewh.ieee.org/soc/es/Nov1997/09/B_WOU1.JPG
=20
=20
The modern equivalent of the older drill is this:
http://www.cpsc.gov/cpscpub/prerel/prhtml02/02234a.jpg
=20
Now you need 18/240 * 80 turns =3D 6 turns and you'll be sucking
a heavy current out of that fat battery pack hanging off the handle.
Intermittent rating is guaranteed, you'll need to recharge the =

The starter motor of your car will only have 1 turn per segment
and will suck 100+ amps from your 12 V car battery, which is
why it has a thick cable.
http://www.driveelectric.org/cars/images/motor_cutaway_1.jpg
=20
Any motor is also a generator if you drive it, so when the
drill is running unloaded it offers impedance (not resistance)
to the current, pushing back against it, and the current drawn is
only that required to overcome friction and air flow from the fan.
Hence copper is used for its minimal resistance (losses to heat)
and the ideal motor would use a superconductor. When the motor
is loaded (drilling a hole through a brick wall to hang a picture
of a fat Phuckwit Duck to laugh at, for example) it will draw more
current. Hence electric motors (and transformers) are efficient, they
only take what energy they need to pass on to the load.
=20
Thin copper with lots of turns for higher voltage operation means
greater resistance but less current. Any resistance at all means heat
and losses.
It also means a greater back EMF (electromotive force) when it is
generating as it spins down, which is why I'm not going to explain
to premji40 how to electrocute himself with his toy magnet running
at 220 V after I did the calculations, and neither should anyone else.
He needs a capacitor across the windings at the very least.
=20
http://www.androcles01.pwp.blueyonder.co.uk/AC/m.gif has
a worn bearing (not shown but the effect is visible). It is also
a one turn per segment low voltage motor.
=20
Higher voltages are desirable for reduced weight of cables, hence:
http://www.allthegoodness.com/images/rainbow_island_pylon.jpg
=20
That's why Edison's DC was a flop and Tesla's AC a success,
but I'm not getting into tesla coils here, a picture will tell all.
http://www.mgvolt.com/tesla_coil/tesla-coil-sparks5.jpg
=20
=20
=20
=20
=20