A PLC is programmed to drive three motors A, B and C as follows : After runni

A PLC is programmed to drive three motors A, B and C as
follows :
After running motor A for an hour, motor B should get ON and
motor A should get OFF.
And after running motor B for an hour, motor C should get ON
and motor B should get OFF.
And after running motor C for an hour, motor A should get ON
and motor C should get OFF.
(That is, a cyclic repetition with time period one hour)

Now, the second condition is:
If any motor gone faulty and is tripped, the consecutive
motor should get ON and
the faulty (tripped) motor should be eliminated from cyclic
repetition.
The remaining two motors should bear the cyclic repetition
of one hour each.
(For healthy motor take logic as high and for tripped motor
take logic as low)

Now, the third condition is:
When motor A load(Amps) exceeds 60% of its rated load, motor
B should get ON in parallel to motor A.
And when both motors A & B are running in parallel, and if
their load exceeds 60% of their rated load,
motor C should also start in parallel to A & B.
[Here the cyclic repetition is eliminated, until their loads
become normal(40%)]
[Take logic high(1) for load at 60% and logic low(0) for
load at 40%]

Now draw a flow chart or a ladder diagram to fulfill the
above condition.

Question Posted / david vara

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