Marine Electrical 2009 Objective Paper


In the illustration, if the device in figure "A" has a step-up ratio of 10 to 1, what voltage should be measured at the secondary shortly after the primary of the device is connected to 110 volts DC?

0 volts

110 volts

11 volts

1100 volts

Answer-0 Volts (Because he is Talking About DC These type of Question is Just to Confuse You)


To prevent the race of a dc series motor what arrangement should make?

A.allways start at heavy load.

B.use a strong series-weak shunt compound dc motor.

C.use a weak series- strong shunt compound dc motor.

D. All of the above.

Answer-C


The armataure resistance of a 200 V d.c. machine has 0.5 ohm. If the full load armature current is 50 A, what will be the induced e.m.f. when, the machine acts as

(i) generator (ii) motor will be

(a) 230 V, 170 V

(b) 210 v, 190 v,

(c) 225 V, 175 C

(d)202.5 V, 197.5 V

Answer-C Because(e=v+ir gen, e=v-ir motor)


the winding resistance of a coil can be increased by___________the number of turns or using a _________wire.

Answer-Increase and Thinner Wire


A FUSE WILL BLOW FOR ALL OF THE LISTED REASON EXCEPT

1. excessive vibration

2. extremely hot surrounding

3. loose fuse clips

4. low contact resistance with the fuse

Answer-4


velocity & impedence of RLC circuit was found by ---------------vector

Answer-Adding the Phase Vector


What happens to the strength of electro magnetic field when current passing through an inductor is halfed ________

a.

b.

c. 2

d. 4

Answer-A


Fuses placed in series with a thermal trip = - type circuit breaker are used for

A.Time-delay protection

B.Short-circuit protection

C.Short duration surge protection

D.Sustained overload protection

Answer-D


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