Electric Motors. Applications. Fans Blowers Machine tools (drill) Appliances (blender, food processor) Wristwatches Disk drives Pumps Etc. How it works. Simply put, an electric motor converts electrical energy into mechanical energy (work)
Applications • Fans • Blowers • Machine tools (drill) • Appliances (blender, food processor) • Wristwatches • Disk drives • Pumps • Etc.
How it works • Simply put, an electric motor converts electrical energy into mechanical energy (work) • They operate through interacting magnetic fields and current-carrying conductors to produce a force • (This might sound familiar)
Parts of a Permanent-magnet motor • Battery • Magnet • Brush • Armature
Brushed DC motor • Oscillating current in wound rotor • Split-ring commutator • Wound or permanent magnet stator • Limitations • friction as brushes press against communtator • sparks can cause shorting through adjacent sections (limits max speed, as melting of the commutator may occur)
LHR for the motor principle • If the thumb points in the direction of the current flow (real current), fingers are the B-field, palm is the force • Iis the current in the conductors, [A] • l is the length of the conductor in the field [m] • Bis the magnetic field, [T]
Time to motor • Motors are easy to make, so let’s try! • Check out the following simple designs and try to identify the parts • Make sure the force on your coil agrees with LHR