Power Generator

151. The synchronous reactance of an alternator ___________ as the iron is saturated

1. decreases
2. remains the same
3. increases
4. becomes doubled

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152. The synchronous reactance of an alternator is due to

1. leakage flux
2. armature reaction
3. dc field excitation
4. hysteresis loss

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153. The temperature rise of a transformer is directly proportional to

1. apparent power
2. leakage reactance
3. reactive power
4. true power

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154. The terminal voltage of a ___________ generator vary widely with changes in load current

1. series
2. flat compounded
3. shunt
4. over compounded

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155. The torque developed by a dc motor is directly proportional to

1. flux per pole x armature current
2. armature resistance x applied voltage
3. armature resistance x armature current
4. flux per pole x applied voltage

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156. The transformer that should never have the secondary open circuited when primary is energized is

1. power transformer
2. auto transformer
3. voltage transformer
4. current transformer

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157. The voltage of the bus bar to which several alternators are paralleled may be raised by simultaneously of all alternators

1. increasing field excitation
2. decreasing field excitation
3. increasing input to prime movers
4. decreasing input to prime movers

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158. The voltage output of a cell depends on

1. its elements
2. electromotive series
3. its electrodes
4. electrochemical series

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159. The voltage per turn of the primary of a transformer is the voltage per turn of the secondary

1. more than
2. the same as
3. less than
4. twice

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160. The voltage regulation of an alternator is larger than of a dc generator because of

1. large armature resistance
2. large leakage reactance
3. complex effects of armature reaction
4. small armature resistance

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