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Power Systems (DC Transmission and Distribution)1. If in a d.c.
2-wire feeder, drop per feeder conductor is 2%, transmission
efficiency ofthe feeder is ........................... percent.(a)
98(b) 94(c) 96(d) 99
2. Transmitted power remaining the same, if supply voltage of a
dc 2-wire feeder is increased by 100 percent,saving in copper is
.......................... percent.(a) 50(b) 25(c) 100(d) 75
3. A uniformly-loaded d.c. distributor is fed at both ends with
equal voltages. As comparedto a similar distributor fed at one end
only, the drop at middle point is(a) one-half(b) one-fourth(c)
one-third(d) twice.
4. In a d.c. 3-wire distributor using balancers and having
unequal loads on the two sides(a) both balancers run as motors(b)
both balancers run as generators(c) balancer connected to
heavily-loaded side runs as a motor(d) balancer connected to
lightly-loaded side runs as a motor.
5. As compared to a dc 2-wire distributor, a 3-wire distributor
with same maximum voltageto earth uses only......................
percent of copper.(a) 66.7(b) 33.3(c) 31.25(d) 150
6. In a d.c. 3-wire distribution system, balancer fields are
cross-connected in order to(a) make both machines run as unloaded
motors.(b) equalize voltages on the positive and negative outers(c)
boost the generated voltage(d) balance loads on both sides of the
neutral.
Answers1. (c) 2. (a) 3. (b) 4. (d) 5. (c) 6. (a)
Power Systems (DC Transmission and Distribution)
