21-03-2014, 11:49 AM
[u]Introduction to DC Motors[/u]
DC Motors.pdf (Size: 56.52 KB / Downloads: 65)
INTRODUCTION
The purpose of this experiment is to examine the construction of a DC
motor/generator, to learn the basic motor wiring connections, and to study the
performance characteristics of a shunt and series dc motor. INSTRUMENTS
AND COMPONENTS:
Power Supply Module (120Vac, 0-120Vdc)
EMS 8821
DC Metering Module (200V, 5A)
EMS 8412
DC Motor/Generator Module
EMS 8211
Connections Leads
EMS 8941
Timing Belt
EMS 8942
Electrodynamometer Module
EMS 8911
Strobotac
BACKGROUND
Direct current motors are unsurpassed for adjustable-speed applications, and for
applications with severe torque requirements. Millions of fractional horsepower DC
motors are used by the transportation industries in automobiles, trains and aircraft
where they drive fans and blowers for air conditioners, heaters and defrosters; they
operate windshield wipers and raise and lower seats and windows. One of their
most useful functions is for the starting of gasoline and Diesel engines in autos,
trucks, buses, tractors and boats.
The DC motor contains a stator and a rotor, the latter being more commonly called
an armature. The stator contains one or more windings per pole, all of which are
designed to carry direct current, thereby setting up a magnetic field.
The armature and its windings are located in the path of this magnetic field, and
when the winding also carries a current, a torque is developed causing the motor to
turn.
CONCLUSION
1. Calculate the starting torques from the t0rque-speed graphs.
2. How does the starting torque vary between motors operating at the same
current?
3. Which motor has better speed regulation and why?