文档介绍：Brushless DC Motors
Sohaib Hasan
Motor Basics
What is a motor
Converts electrical energy into kinetic energy
Where did it come from
Identification of rotating magnetic field principle by Nicola Tesla in 1882
Introduction of Electric Motor by Nicola Tesla in December 1889 (. Patent 0416194)
Parts of a Motor
End Bell Fastners
Shaft Key & Keyways
Bearing & Brushings
End Ball Flanges
Identification Plates
Wire Warnish
Commutators
Brush Holders
Laminations
Conduit Connection Box
Magnets (Ferrites)
Brushless Motor Components
Brush Type Motor Components
Images courtesy of Hernon Adhesives & Sealents
()
Parts of a Motor
Images courtesy of How Stuff Works
()
How It Works
When electric current passes through a coil in a magnetic field, the magnetic force produces a torque which turns the motor.
Force in Motor:
F=ILB
F = Force
B = Magnetic Field
L = Length of Conductor
I = Current in Conductor
Torque in Motor:
T = IBA sin θ
A = LW
L = Length of Winding
W = Width of Winding
Images courtesy of Wikipedia
()
Motor Types
Brushless DC Motor
No Commutators
Position of Coils with respect to the magnetic field is sensed electronically.
Current is commutated through electronic switches to appropriate phases.
How it Works
Halls Sensors sense the position of the coils
The Decoder Circuit turns appropriate switches on and off
The voltage through the specific coils turns the motor
Images courtesy of Servo Magnetics
(-pole/2pole-bldc-)
Advantages
Increased Reliablilty & Efficiency
Longer Life
Elimination of Sparks from Commutator
Reduced Friction
Faster Rate of Voltage & Current
Precision Voltage & Current Applied to Field Coils
Applications
Low Power
Consumer Electronics
Medical Field
High Power
Industria