Electric Motor

Electric Motor - Transcript

Electric Motor Electric
By Princess Barcega APG School

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Magnetic Force On A Current Carrying Conductor
The magnetic force F the conductor experiences is equal to the product of its length L within the field the current I in the conductor the external magnetic field B and the sine of the angle between the conductor and the magnetic field In short conductor F BIL sin F

The force on a current carrying The carrying conductor in a magnetic field conductor
When a current carrying conductor is placed in a When carrying magnetic field there is an interaction between the magnetic field produced by the current and the permanent field which leads to a force being force experienced by the conductor experienced

The magnitude of the force on the conductor depends on the magnitude of the current which it carries The on force is a maximum when the current flows perpendicular to the field as shown in diagram A on perpendicular the left below and it is zero when it flows parallel to parallel the field as in diagram B on the right the

Fleming s left hand rule Fleming s

The directional relationship of I in the conductor the external magnetic field and the force the conductor experiences experiences

I B F

Motion of a current carrying loop in a magnetic field magnetic

F

Rotation I

N
brushes

L

R F

S
Commutator rotates with coil

Vertical position of the loop Vertical
Rotation

N

S

Electric Motor Electric
An electromagnet is the basis of an An electric motor An electric motor is all about magnets and magnetism A motor uses magnets to magnetism magnets create motion Opposites attract and likes repel Inside an Opposites electric motor these attracting and repelling forces create rotational motion rotational A motor is consist of two magnets motor

Parts of the Motor Parts
Armature or rotor Armature Commutator Brushes Axle Field magnet DC power supply of some sort DC

Motor Illustration Motor

Armature Armature
The armature is an The electromagnet made by coiling thin wire around two or more poles of a metal core metal The armature has an axle axle and the commutator is attached to the axle When you run electricity into this electromagnet it creates a magnetic field in the armature that attracts and repels the magnets in the stator So the armature spins stator through 180 degrees through To keep it spinning you have To to change the poles of the electromagnet electromagnet

Commutator and Brushes Commutator
Commutator is simply a pair of plates Commutator attached to the axle These plates provide attached the two connections for the coil of the electromagnet electromagnet Commutator and brushes work together to let current flow to the electromagnet and also to flip the direction that the electrons are flowing at just the right moment are

The contacts of the commutator are attached to the axle of the electromagnet so they spin with the magnet The brushes are just two pieces of the springy metal or carbon that make contact with the contacts of the commutator the

Spinning Armature Spinning

Example of Motor Example

Answer the questions Answer

A current carrying coil in a magnetic field experiences a turning effect

How can the turning effect be increased A increase the number of turns on the coil B reduce the size of the current C reverse the direction of the magnetic field D use thinner wire for the coil

What are the directions of the force in the left and right loop and

A student sets up the apparatus shown in order to make a relay

Which metal should be used to make the core A aluminium B copper D steel C iron