29-07-2011, 03:23 PM
[attachment=14901]
AIM
To draw the V and inverted V curves of a 3 phase Synchronous Motor.
NAME PLATE DETAILS:
3ǾSYNCHRONOUS MOTOR DC EXCITATION
FUSE RATING:l
125% of rated current (full load current)
For DC excitation:
For synchronous motor:]
PRECAUTION:
(1) The Potential barrier should be in maximum position.
(2) The motor should be started without load .
(3) Initially TPST switch is in open position.
PROCEDURE:
(1) Note down the name plate details of the motor.
(2) Connections are made as pr the circuit diagram..
(3) Close the TPST switch.
(4) By adjustingthe autotransformer from the minimum position to the maximum position the rated supply is given to motor. The motor starts as an induction motor.
(5) In order to give the excitation to the field for making it to run as the synchronous motor, close the DPST switch.
(6) By varying the field rheostat note down the excitation current, armature current and the power factor for various values of excitation.
(7) The same process has to be repeatedfor loaded condition.
(8) Later the motor is switched offand the graph is drawn.
GRAPH:
The graph is drawn for-
(1) Armature current Vs Excitation current.
(2) Power factor Vs Excitation current.
RESULT:
The V-curves and inverted V-curves of the 4 phase synchronous motor have been drawn.
