19-10-2010, 02:26 PM
Motors_F09.ppt (Size: 3.22 MB / Downloads: 377)
Motors
Sean DeHart
Smriti Chopra
Hannes Daepp
Electric Motor Basic Principles
Interaction between magnetic field and current carrying wire produces a force
Opposite of a generator
Conventional (Brushed) DC Motors
Permanent magnets for outer stator
Rotating coils for inner rotor
Commutation performed with metal contact brushes and contacts designed to reverse the polarity of the rotor as it reaches horizontal
Common Applications:
Small/cheap devices such as toys, electric tooth brushes, small drills
Lab 3
Pros:
Cheap, simple
Easy to control - speed is governed by the voltage and torque by the current through the armature
Cons:
Mechanical brushes - electrical noise, arcing, sparking, friction, wear, inefficient, shorting