SPEED CONTROL OF DC SHUNT MOTOR - Computer Programming

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Monday, April 4, 2011

SPEED CONTROL OF DC SHUNT MOTOR
AIM:
To obtain speed control of DC shunt motor by
1. Varying armature voltage with field current constant.
2. Varying field current with armature voltage constant

APPARATUS REQUIRED:
 S.No. Apparatus Range Type Quantity 1 Ammeter (0-20) A MC 1 2 Voltmeter (0-300) V MC 1 3 Rheostats 1250W, 0.8A50W, 3.5A Wire Wound Each 1 4 Tachometer (0-3000) rpm Digital 1 5 Connecting Wires 2.5sq.mm. Copper Few

PRECAUTIONS:
1. Field Rheostat should be kept in the minimum resistance position at the time of starting and stopping the motor.
2. Armature Rheostat should be kept in the maximum resistance position at the time of starting and stopping the motor.

PROCEDURE:
1. Connections are made as per the circuit diagram.
2. After checking the maximum position of armature rheostat and minimum position of field rheostat, DPST switch is closed
(i)    Armature Control:
1. Field current is fixed to various values and for each fixed value, by varying the armature rheostat, speed is noted for various voltages across the armature.
(ii)  Field Control:
1. Armature voltage is fixed to various values and for each fixed value, by adjusting
the field rheostat, speed is noted for various field currents.
2. Bringing field rheostat to minimum position and armature rheostat to maximum
position DPST switch is opened.

TABULAR COLUMN:
(i) Armature Voltage Control:
 S.No. If1 = If2 = If3 = Armature VoltageVa ( Volts) SpeedN (rpm) Armature VoltageVa ( Volts) SpeedN (rpm) Armature VoltageVa ( Volts) SpeedN (rpm)

(ii) Field Control:
 S.No. Va1 = Va2 = Va3 = Field CurrentIf (A) SpeedN (rpm) Field CurrentIf (A) SpeedN (rpm) Field CurrentIf (A) SpeedN (rpm)

MODEL GRAPHS:

RESULT:
Thus the speed control of DC Shunt Motor is obtained using Armature and Field control methods.