A dc motor running on dc drive whose input is 3ph AC what
will happen if we change the phase sequence of dc drive for
e.g (R Y B) is connect as R B Y, will the motor run as same
as previously running before changing phase without any effect
Answers were Sorted based on User's Feedback
Answer / dinesh lokhande
Basically DC drive consists of Thyristor controlled
rectifier circuit which converts AC to DC and provides
supply to motor armature. As per arrangement of thyristor
circuit DC polarity always remains constant inspite of
change in AC supply phase sequence.
Thus there will not be any change in motor performance.
My answer may be wrong....
If anybody knows the firm answer can correct me...
|Is This Answer Correct ?||12 Yes||2 No|
Answer / anil bhatia
this answer is for Mr Arun Kokje . you can ask equation in proper place not in answer side .find the initial current and time to reach this motor to run in running in full speed current. the initial impedance of this motor is very low (300HP), it is just create like near to sort circuit current for 1250 KVA DG.
soft starter will solve your problem .
|Is This Answer Correct ?||1 Yes||0 No|
Answer / arun kokje
I HAVE GIVEN MY ANSWER AS YES BECAUSE BY CHANGING AC INPUT
PHASES THE POLARITY OF DC OUTPUT SHALL REMAIN SAME HENCE NO
CHANGE IN DIRECTION OF MOTOR. I HAVE ONE QUESTION AS WHAT
WILL HAPPEN IF THE DC DRIVE OF SAY 300HP MOTOR WILL VRUN
THROUGH 1250KVA CAPACITY D.G. SET INSTEAD OF RUNNING ON
GRID. I RUN ON GRID WHEN IT WAS RUNNING SMOOTH BUT WHEN I
RUN ON DG SET IT WAS GIVING HUNTING IN VOLTS,CURRENT AND SPEED.
|Is This Answer Correct ?||0 Yes||0 No|
Answer / nimda
The dc drive may not work at all if you connect your input
power with wrong phase sequence because the firing pulses to
the thyristors will be in wrong sequence. So the motor may
not start at all. There are different types of dc motors but
usually the direction of rotation doesn't change by changing
the polarity at the power source. To change the direction of
rotation you must usually swap either the polarity of the
field winding or the polarity of the rotor winding.
|Is This Answer Correct ?||1 Yes||1 No|
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