Electric Motor

Electric Motor - Electric Motor Electric By Princess Barcega APG School Powerpoint hosted on www.worldofteaching.com Please visit for 100’s more

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Unformatted text preview: Electric Motor Electric By Princess Barcega APG School Powerpoint hosted on www.worldofteaching.com Please visit for 100’s more free powerpoints 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 (sinθ) 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 ...
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This note was uploaded on 11/08/2011 for the course PHYSICS 121 taught by Professor Richardvanfleet during the Winter '09 term at BYU.

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