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

Answer Posted / 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.

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