Ward Leonard Speed Control System for a DC Motor with Diagram

As a very flexible, reliable means of motor speed control, the Ward Leonard System is unmatched.

The system is made up of a driving motor which runs at almost constant speed and powers a dc generator as shown in the diagram. The generator output is fed to a dc motor. By varying the generator field current, its output voltage will change. The speed of the controlled motor thus can be varied smoothly from zero to full speed. 


Since control is achieved through the generator shunt field current, the control equipment is required only for small current values. A potentiometer or rheostat in the generator field circuit enables he variation of output voltage from zero to the full value and also in either direction. The controlled motor has a constant excitation. Its speed and direction are thus determined by the generator output. 


Depending upon the particular duties of the controlled motor, series windings may be incorporated in the field of the motor and also the generator. This may result in additional switching to reverse the controlled motor depending upon the compounding arrangements.

The driving motor or prime motor for the Ward Leonard System can be a dc motor, an ac motor, a diesel engine, etc. Any form of constant and almost constant speed drive can be used, since its function is only to drive the generator.


References

"Introduction to Marine Engineering" by T.A. Taylor





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www.marineengineeringonline.com




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Comments 12 comments

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thevoice 6 years ago from carthage ill

well explained hub thanks


peter GIZO 6 years ago

WHAT IS THE USE OF THE RECTIFIER IN THE DIAGRAME?


jinnu 6 years ago

what would be the panel diagram of this (word-leonard) method


aung_comy@yahoo.com 5 years ago

THE RECTIFIER IS USE DC SUPPLY FOR FEED TO GENERATOR AND MOTOR FIELD WINDING. BECAUSE THE FIELD WINDING HAVE TO USE DC CURRENT IN ORDER TO GET THE CONSTANT DC OUT PUT VOLTAGE.


tandroid 5 years ago

I actually understood for once.


REY 4 years ago

thanx,,,,i got wat i was searching for


Brian Hodgson 4 years ago

Very good explanation thank you


sateesh 4 years ago

very simple expalnation


Lawrence 4 years ago

Perfect explanation.


I. Comfort 4 years ago

Very simplified


I. Comfort 4 years ago

Very simplified


praveen k d 2 years ago

nice explain

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