الفهرس 
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Abstract
This work presents a detailed study for the speed control of fraction horse-power universal motors. The control methods described here, employe thyristorized control circuits connected in series with the motor when it is supplied from an A,C.source. The speed control is achievd by varying the triggering angle in an open loop or a closed loop system. WHEN THE MOTOR IS SUPPLIED from A FULLY CONTROLLED RECTIFIER BRIDGE, THE SPEED CONTROL MAY ALSO BE ACHIEVED BY THE SAME THYRISTOR CIRCUI USED ABOVE. Afree-wheeling diode may be used with the fully controlled bridge or free-wheeling action may occur if a plain rectifier bridge is used in series with a triac.
Atheotetical study of universal motors when fed from uncontrolled A.C or D.C. supply is given. This analysis covers both the steady and transient states. The effect of feeding the motor from a controlled A.C. or D.C.supply is investigated. Performance characteristics of the motor are then obtained under different modes of operation.
An experimental model was built and tested to verify the theoritical results. Experimental results were found to be in a close agreement with theoritical results.