問題一覧
1
On an aircraft DC generator the pole pieces are :
electromagnets
2
the most common type used at the A/C
is Shunt wound
3
The coil ends connected to adjacent commutator segment :
Lap winding
4
The speed of a series motor is dependent
upon the load.
5
If the heavy mechanical load is removed from a series motor the speed will:
increased and the armature current will decrease.
6
If a DC shunt motor lost its residual magnetism it would :
run normally
7
Additional generator poles in a DC motors are provided
to Compensation for the armature reaction
8
The current consumed is decreased as the
rotation speed increased while starting in the DC motor.
9
Armature reaction is when:
field excited, armature excited.
10
To decrease the arcing at the brushes in a high output generators we
add interpoles and compensating winding
11
In the series motor, the field windings, consisting of a relatively :
few turns of heavy wire
12
Number of cycle completed per second :
frequency
13
Alternating polarity from an alternator takes on a distinct shape, known
as a sine wave.
14
Root mean square:
is the equivalent DC heating effect
15
The peak value of an aircraft 115v single phase is :
162.6
16
A sine wave of RMS value 7.06 volts has a peak to peak value of.
20 volt
17
Peak value=
RMS/0.707
18
The form factor of an AC waveform can be found by :
RMS value divided by the average value
19
Square-shaped waveforms always have crest and form factors equal to 1, since
the peak is the same as the RMS and average values
20
Three phase
star connection(Y)
21
Split phase means:
single phase
22
Line voltage with a delta type connection will be the same as
phase voltage.
23
The max. Value of voltage in either (+ve) or (– ve) direction is.
The peak value
24
The AC waveform has mark-to-space ratio 0.5 this means :
the space is twice the mark
25
constant direction :
direct current
26
The Form Factor of an AC waveform can be found by.
RMS value divided by the average value