1. L.W.T.R for small A/C
Airplane & System Description
Prepared by : Eng. Raeed Tarek Gouda
A/C Electric
Customized by: Eng. Shady Youssef
12/26/2022 1
5. Electric
1- Power sources
I. Battery.
Battery Functions.
Battery Principle of Operation.
Battery Construction.
Types of Batteries.
Battery Location.
Battery removal and installation
Battery Charging & Discharging.
Battery Capacity and Discharge Rates.
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6. Electric
1- Power sources
I. Battery.
Battery Functions.
A. Transient conditions. (At starting large D.C motor…)
B. Supplying power for short term to heavy loads. (when
generator or ground power is not available, at Engine).
C. Emergency conditions.(to operate flight instruments…For
30 min as the capacity of the batteries allow).
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7. Electric
1- Power sources
I. Battery.
Battery Principle of Operation.
Conversion of Chemical Energy into Electrical Energy.
This is done by the exchange of electrons due to the
chemical reaction between the Electrodes and the
Electrolyte.
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8. Electric
1- Power sources
I. Battery.
Battery Construction.
An aircraft battery consists of a number of
individual cells interconnected together.
It contain separators between plates.
Each cell consists of an odd number of -Ve plates
and even number of +Ve plates.
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9. Electric
1- Power sources
I. Battery.
Types of Batteries.
Lead Acid battery.
Nickel-Cadmium battery.
Battery type is derived from the plate material (electrodes)
and liquid (electrolyte) that is used during construction.
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10. Electric
1- Power sources
I. Battery.
Battery Charging & Discharging.
Battery will be CHARGING when the generator is
operating or external power is applied.
Whenever a battery is supplying power, it is said to be
DISCHARGING.
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11. Electric
1- Power sources
I. Battery.
Battery Location.
Batteries located within the aircraft's main electrical
equipment bay where “Adequate heat dissipation,
ventilation and protection is provided”.
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12. 1- Power sources
I. Battery.
Removal
• Detach the negative (black)
• Detach the positive (red) battery cable from the battery
Installation
• Detach the (red) battery cable from the battery
• Detach the negative (black)
Battery installation and removal .
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13. Electric
1- Power sources
I. Battery.
Battery Capacity and Discharge Rates
The maximum current, in AMPERES, which the battery will
deliver for a known time period, in HOURS, until the output
voltage has fallen to minimum value.
It depend on the:
Discharge Rate
It is the time taken to discharge until a allowable minimum
voltage.
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14. Electric
1- Power sources
II. Generators.
Power Generation Theory.
Types of Generators.
Generators protection.
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15. Electric
1- Power sources
II. Generators.
Power Generation Theory.
A Generator is a machine that converts mechanical energy into
electrical energy by process of electromagnetic induction “Magnetic
Principles”.
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16. Electric
1- Power sources
II. Generators.
Types of Generators.
D.C & A.C Generator
In both DC. and AC. types, the voltage induced is Alternating.
The difference is in the method by which electric energy is
collected and applied to the circuit externally connected to the
generators.
In DC. Generator the collector is commutator
In AC. Generator the collector is Slip Rings
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 16
17. Electric
1- Power sources
II. Generators.
Types of Generators.
D.C Generator
A.C Generator
Alternator (3 phase A.C generator with built-in rectifier).
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 17
18. Electric
1- Power sources
II. Generators.
Types of Generators.
Alternator.
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 18
19. Electric
1- Power sources
III. Power conversion.
Static Inverter.
it’s convert DC AC
28 V DC 115 V AC , 400 Hz
The advantages of a static inverter are:-
• High efficiency & Low weight.
• Low maintenance and long life.
• not need warm up time.
• Quiet in operation.
• Has a fast response to load changes.
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 19
20. Electric
1- Power sources
III. Power conversion.
Rectifier circuit
it’s convert AC DC
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 20
22. Electric
2- Protection.
I. Fuses.
Is thermal device designed to protect the cable and
circuit against the flow of short circuit and over load
currents .
Use for one time.
II. Current limiter.
is thermal device designed to limit the current but not
like fuse it has high melting point.
Also use for one time.
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 22
23. Electric
2- Protection.
III. Circuit breakers.
It’s mechanical trip device actuated by the heating of a
bi-metallic element .
It’s can closed and open the circuit manually or
automatically under all conditions ( no load ـــfull
load– short circuit )
It’s very useful equipment for switching such as ( ADF ,
NAV, DME , ………)
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 23
24. Electric
2- Protection.
IV. Relays
It’s a device use to connect between two high
voltage point controlled by coil.
It’s a device use to protect from over high
voltage .
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 24
27. Electric
1- Power sources
I. Battery Or External Power .
II. Generator( Alternator + External Power).
III. Power conversion Equipment.
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 27
28. Electric
1- Power sources
I. Battery.
Only one main battery.
It’s Lead –Acid battery with 24
V,12.75Amp/Hrs. (5 hours –rate).
Its’ location is inside the engine cowling on
left firewall
It’s Emergency component so should be in
fully charged state at all times.
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 28
29. Electric
1- Power sources
I. Battery.
Standby battery located between the firewall
and the instrument panel
the standby battery will give power to the
essential bus for a period of time in the even
that the alternator and main battery has
been failed.
the battery capacity is 8 amp-hour
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 29
30. Electric
1- Power sources
II. Alternator
It’s Belt driven alternator with 28 volt DC.
60 Ampere alternator Powers the system.
Its’ location on the forward side of the engine, below
and to the right of the crankshaft.
The Alternator controlled by ACU (Alternator control
unit )
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 30
31. Electric
1- Power sources
II. External power
An external power receptacle is located in left side of
engine cowl near of firewall and accepts a standard
AN-type plug.
The power unit should be capable of delivering at
least 300 Amperes for starting.
The volt not higher than 30 volt.
The battery should be left on to absorb any transient
electrical spikes & all avionics and electrical switches
must be off.
Prepared by : Eng. Raeed Tarek Gouda
12/26/2022 31
