# GCSE Physics (19/05) The Motor EffectWatch

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Thread starter 5 years ago
#1
I was just wondering with Unit 3 coming up in Physics tomorrow, what exactly is the motor effect. I know a coil "experiences a force" but is this force due to a magnetic field being created, which repels the magnets either side of the coil?

I'd just appreciate it if someone could simply the whole motor effect thing for me as the revision guide doesn't explain it greatly.

Thanks
0
5 years ago
#2
Ah.. The Motor Effect:
The wire which you put in between the permanent magnet creates two magnetic fields- one from passing current through the wire and the other is the usual magnetic field surrounding a permanent magnet. These two fields interact to produce a force (either up or down). You find out whether it's up/down using Fleming's left-hand law!
Thumb= Motion
First Finger= Magnetic field (North to South)
Second Finger- Direction of the flow of current
Because the motor effect results in a force, you can use it to produce movement: (In the spec, you're expected to know how a Simple d.c electric motor works)
1. Loop of wire placed in a magnetic field
2. d.c current flows through the loop of wire.. the two sides of wire ('arms' near N and S) experience a force in Opposite directions because direction of current in each 'arm' is opposite.
3. Essentially, this is what causes the loop to rotate around it's axis (one force acts up, one force acts down)
4. There'll be a point when the loop reaches a vertical position; the forces will start acting (one up and one down) on the same arms of the loop, the loop gets stuck. You can keep the motor rotating by swapping the direction the forces are acting on.
5. A split-ring communicator can do this: it swaps the loop every half-turn! This also reverses current direction.

This is a simple as I could explain the goddamn Motor Effect.. I hope I helped..? Good luck with your exams tomorrow!
1
5 years ago
#3
Essentially, the current through the wire creates a magnetic field which interacts with the permanent field to create a force. This force is then harnessed by having the current flow in opposite directions which causes an opposite pair of forces which cause the motor to spin. A split ring commutator is used to maintain the forces in the correct directions.

Click here if you want more explanation.

http://www.thestudentroom.co.uk/show....php?t=2634601

Posted from TSR Mobile
1
Thread starter 5 years ago
#4
Thank you both for the replies, I'll be looking forward to a question on the motor effect now
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