DC Electrics - DC Motors 7
Electromagnetic Indicators
The electromagnetic indicator was introduced as a replacement for the simple filament lamp indicator.
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ElectricsDC |
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OPEN |
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O P E N |
DOLLS EYE |
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PRISM |
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Figure 7.11 |
Electromagnetic indicators |
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The types in common use are the doll’s eye and prism indicators which are illustrated in Figure 7.11. The pictorial presentations offered by these indicators are further improved by the painting of ‘flow lines’ on the appropriate panels so that they interconnect the indicators with the system control switches, essential indicators and warning lights.
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Questions |
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1. |
Rotary actuators are used for: |
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a. |
undercarriage retraction |
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b. |
centre of gravity assessment |
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c. |
operation of fuel cocks |
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d. |
movement of control surfaces |
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2. |
Actuator normal travel is controlled by: |
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a. |
a clutch |
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b. |
limit microswitches |
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c. |
mechanical indicators |
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d. |
mechanical stops |
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3. |
On a twin engined DC aircraft having two DC generators load sharing is achieved |
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by: |
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a. |
equalizing engine RPMs |
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b. |
an equalizing circuit to sense the difference and equalize the voltages of the |
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two generators |
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c. |
synchronizing relays and voltage coil tuners |
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d. |
an equalizing circuit to sense the difference and equalize the field currents of |
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the two generators |
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4. |
Pilots are informed of rotary actuator positions by: |
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a. |
non-return valves |
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b. |
lights or doll’s eye indicators |
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c. |
travel indicators |
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d. |
veger counters |
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5. |
Press-to-test lights are used: |
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a. |
to indicate to the pilot that the circuit has power and is complete |
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b. |
to control the movement of a rotary actuator |
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c. |
to indicate to the pilot that the circuit has operated |
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d. |
only to indicate to the pilot that the equipment has malfunctioned |
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6. |
A device for changing AC to DC is: |
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a. |
an inverter |
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b. |
a rotary transformer |
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c. |
a rectifier |
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d. |
an alternator |
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7. |
An inching control is used in conjunction with: |
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a. |
a linear actuator |
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b. |
a rotary actuator |
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c. |
a combination of linear and rotary actuator |
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d. |
a rectifier |
116
Questions 7
8.Friction clutches are fitted to actuators for:
a.protection against mechanical overload
b.protection against brake on loads
c.protection against non-return valve failure
d.protection against supply failures
Questions 7
117
7 Answers
Answers
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Answers 7
118