a very dumb motor question (1 Viewer)

[...]

what is an emf...like not the definition...

can someone show me(possibly a diagram) cos looking at Jacaranda and other resources...they all of a sudden shove it the term there without explaining it

boy, Motors and Generators shits me the most...

 

[+:: $i[Q]u3 ::+]

emf is just another word for the voltage (a potential difference).... like.... it just means there's a current through the wire...

what do u want a diagram of?

 

[sukiyaki]

emf - change of flux over time

hmm i dont think i could get a diagram -.-

 

[t-i-m-m-y]

emf= electromotive force

which produces a potential difference

emf is proportional to the rate of change of flux over time

emf=d(phi)/dt ---> if u can understand that

 

[Fosweb]

Originally posted by t-i-m-m-y
emf= electromotive force

which produces a potential difference

Try not to get confused using the word 'force' - its not really a force. Its a voltage. (It was just called the electromotive force.)

 

[...]

Originally posted by sukiyaki
emf - change of flux over time

hmm i dont think i could get a diagram -.-

ahh..that will make things a bit more simple...

Originally posted by t-i-m-m-y
emf= electromotive force

emf=d(phi)/dt ---> if u can understand that

thought it was - d(phi)/dt

 

[Ragerunner]

Know your faraday's law as well

The size of the induced emf is proportional to the rate at which the conductor cuts the magnetic field lines

 

[...]

yea, i'm currently doing M&G...

dun really like the topic...

 

[wogboy]

Don't forget to multiply by N (the number of turns) when you have a coil with multiple turns.

e = N * d@/dt (Faraday's Law)

e = EMF (Volts)
@ = magnetic flux (Wb or Tm^2)
t = time (s)

Technically emf is defined as the amount of energy per unit charge. A changing amount of magnetic flux through a coil supplies a quantity of (electrical) energy to each conduction electron in the metal wire of the coil. You can work out this amount of energy supplied to each electron by dividing the EMF, by the number of conduction electrons in the coil.

 

[ratherbesleepin]

Are we actually supposed to know that equation
e = N * d@/dt (Faraday's Law)

Cause i never seen it before in my life

it wouldn't surprise me if my teacher just 'missed' it

 

[elizabethy]

EMF IS AN ELECTROMOTIVE FORCE THAT OPPOSES THE MAIN CURRENT FLOW IN A CIRCUIT!!

 

[Hotdog1]

Isnt that only the back emf though?

 

[NSBHSchoolie]

You just need to remember 2 things:
1) It's not a force, it's really voltage or energy (same same)
2) It's an induced voltage.

 

[t-i-m-m-y]

yes emf also happens in chemistry- for those of u who don't do it.. and yes its not a force- it causes a potential difference, if hooked into a completed circuit

*brings back dreaded memories of galvanic cells

 

[allyteaded]

Originally posted by +:: $i[Q]u3 ::+
emf is just another word for the voltage (a potential difference).... like.... it just means there's a current through the wire...

emf is not a current, it's a potential difference. If the circuit is completed, then current is allowed to flow.

And yes, Elizabethy defined back emf. But dude, what's with the capitals? Can't find the capslock key?

oh and timmy, what's wrong with linux? I know this is OT but your avatar is so cruel...

 

[t-i-m-m-y]

Originally posted by allyteaded

oh and timmy, what's wrong with linux? I know this is OT but your avatar is so cruel...

oh.. i just found the avatar off the net and photoshopped it- i have nothing against linux