7
1-63. The output voltage of a control
transformer on electrical zero is which of
the following relative values?
1. Equal to the supply voltage
2. Half the supply voltage
3. Maximum
4. Minimum
1-64. When a tri-speed synchro system is being
zeroed, which synchro should be zeroed
first?
1. Coarse
2. Medium
3. Largest
4. Fine
1-65. What method of zeroing a synchro is the
fastest but NOT the most accurate?
1. The dc voltmeter method
2. The ac voltmeter method
3. The synchro-tester method
4. The electrical-lock method
1-66. The electrical-lock method of zeroing a
synchro requires accessible leads and
which of the following conditions?
1. A rotor free to turn
2. A stator free to turn
3. A supply voltage to the stators
4. A zero-volt potential between S1 and
S2
1-67. A synchro is zeroed by the use of a
synchro tester. After it is zeroed, the S1
and S3 leads are shorted together, and the
synchro tester dial moves. What does
this indicate?
1. The synchro is zeroed correctly
2. The synchro is not zeroed correctly
3. The supply voltage is too low
4. The supply voltage is too high
1-68. If you find that a synchro has bad
bearings, which of the following actions
should you take?
1. Replace the bearing
2. Lubricate the synchro
3. Replace the synchro
4. Continue to use it
1-69. Which of the following troubles is
common in newly installed synchro
systems?
1. Dirty brushes
2. Improper wiring
3. Worn slip rings
4. Shorted synchro windings
1-70. What type of indicating device is usually
installed in the stator circuit of a torque
synchro system?
1. A voltmeter indicator
2. An ohmmeter indicator
3. An overload indicator
4. A blown-fuse indicator
1-71. A synchro system with four receivers is
malfunctioning. All of the receivers have
incorrect readings. Which of the
following is/are the most likely cause(s)
of the trouble?
1. Damper failure
2. The transmitter
3. One of the receivers
4. All of the receivers
1-72. An ac voltmeter is connected between
windings S1 and S3 of a synchro
transmitter. Which of the following rotor
positions should give a zero voltage
reading?
1.
180º
2.
240º
3.
300º
4.
330º
