Traction motor refers to an
electric motor providing the primary rotational torque of a machine, usually for conversion into
linear motion (
traction).
Traction motors are used in electrically powered rail vehicles such as
electric multiple units and
electric locomotives, other electric vehicles such as
electric milk floats,
elevators and
conveyors as well as vehicles with electrical transmission systems such as
diesel-electric, electric
hybrid vehicles and
battery electric vehicles. Additionally, electric motors in other products (such as the main motor in a
washing machine) are described as traction motors.
Transportation applications
Railroad
Traditionally, these were
series-wound brushed DC motors, usually running on approximately 600 volts. The availability of high-powered semiconductors (such as
thyristors and the
IGBT) has now made practical the use of much simpler, higher-reliability
AC induction motors known as asynchronous traction motors.
Synchronous AC motor are also occasionally used, as in the French
TGV.
Before the mid-20th century, a single large motor was often used to drive multiple
driving wheels through
connecting rod that were very similar to those used on
steam locomotives. Examples are the
Pennsylvania Railroad DD1,
FF1 and
L5 and the various
Swiss Crocodiles. It is now standard practice to provide one traction motor driving each axle through a gear drive.
Usually, the traction motor is three-point suspended between the
bogie frame and the driven...
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