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AIM:
To synchronize and operate the two electric sources in parallel with bus bar arrangement and draw the performance characteristic curves.
NAME PLATE DETAILS:
3Ǿ alternator DC shunt motor 3ǾLoad
FUSE RATING:
125% of rated current (full load current)
For DC shunt motor:
For ac alternator
PRECAUTIONS:
(1) The motor field rheostat should be in minimum resistance position.
(2) The Alternator field Potential divider should be at minimum voltage position.
(3) Initially all switches are in open position.
PROCEDURE:
SYNCHRONISATION:
(1) Note down the name plate details of motor and alternator.
(2) Connections are made as per the circuit diagram.
(3) Close the DPST switch.
(4) Using the 3-point starter start the motor, by varying motor field rheostat.
(5) By varying the potential divider , generated voltage is built up to rated voltage.
(6) Now close the TPST switch.
(7) TPST is closed and by varying the potential divider the field current is varied so that voltmeter reads the same voltage as measured above.
(8) When TPST is closed the lamps may flicker uniformly.
(9) If flickering is not uniform then the phase sequences of any two lines are changed.
(10) Now synchronization switch is closed when lamps are in dark period .
(11) Now the two sources are synchronized.
LOAD SHARING
(1) Connect the synchronized output with variable load.
(2) For various loads, note all the corresponding ammeter and voltmeter readings.
(3) Draw the graph between respective voltage and currents (V1 Vs V2, V2 Vs I1 and V1 Vs I1.).
V-CURVE
(1) After synchronization the prime mover should be switched off and
Potential divider should be brought to the maximum position.
(2) By adjusting the potential barrier tabulate the various Field currents
and corresponding Armature readings.
(3) To obtain V- curve draw the graph between Armature current and
Field current
RESULT:
The 3 phase alternator has been synchronized with the bus bars and the load characteristics obtained.