Traction application -- Which type of motor is best?

[smruti]

in traction applications which motor is best suitable? previoulsy dc series motors were used in traction applications due to there excellent starting torque.but now a days it is being replaced by induction motors.why can't we employ synchronous machine in traction application?

 

[Jeff Rosenbury]

What is a traction application?

It sounds like the drive wheel on an electric vehicle/robot.

I can easily foresee problems when the torque is so high the wheels lose traction on starting. In the case of an automobile, the weight of the electric motor would be unsprung weight, so choosing a motor that matches the needed performance with minimal weight is a high priority. Then there are safety issues. What happens when the electronics blow at 70mph? Then there are power feed issues.

This is a very tricky bit of engineering with lots of variables. Hopefully those involved have considered the options. Still, perhaps you can build a better mousetrap.

 

[Windadct]

Traction typically refers to rail - the induction motors cost less. Since they would both require a VF drive - the Eff of the induction motor is good enough, and the drive does allow pretty high torque at low speed.

 

[FOIWATER]

It has to do with control. In older traction applications involving DC motors (electric trains, electric vehicles (see komatsu fleet of 930E electric drive train), contactors are used for control. Due to the advent and easy implentation of power electronics (I am thinking IGBT) which allow you to convert a DC signal into a variable AC signal (better control of the frequency) You get better speed control.

Also induction motors have far less maintenance. I used to work as an industrial electrician maintaining a fleet of komatsu haul trucks (we had both AC and DC drive systems).

A frequent cause for maintenance was motor flashing (DC) and brush wear. Never once did I ever see a AC traction motor fail.

 

[smruti]

It has to do with control. In older traction applications involving DC motors (electric trains, electric vehicles (see komatsu fleet of 930E electric drive train), contactors are used for control. Due to the advent and easy implentation of power electronics (I am thinking IGBT) which allow you to convert a DC signal into a variable AC signal (better control of the frequency) You get better speed control.

Also induction motors have far less maintenance. I used to work as an industrial electrician maintaining a fleet of komatsu haul trucks (we had both AC and DC drive systems).

A frequent cause for maintenance was motor flashing (DC) and brush wear. Never once did I ever see a AC traction motor fail.

thank you...