aircraft electrical systems ted spitzmiller 1aircraft electrical systems
TRANSCRIPT
AircraftElectrical Systems
Ted Spitzmiller
1Aircraft Electrical Systems
C-182T Electrical System
2Aircraft Electrical Systems
What is Electricity?
• Flow of electrons from one atom to another
+-
3Aircraft Electrical Systems
Like a bucket brigade
4Aircraft Electrical Systems
Where do we get ‘positive 'attraction—from a battery…
5Aircraft Electrical Systems
Putting some ‘resistance’ into the flow provides useful ‘work’
6Aircraft Electrical Systems
‘Current’ flows in the opposite direction to the electrons
• Voltage (E) is the ‘pressure’ of the electrons
• Measured in Volts
• Current (I) is the ‘amount’ of electrons flowing
• Measured in AmpsE
7Aircraft Electrical Systems
Moving a coil in a magnet generates electricity to recharge the battery
8Aircraft Electrical Systems
Two types of ‘current’
9Aircraft Electrical Systems
10Aircraft Electrical Systems
Why is Electricity Dangerous• Minimum current a human can feel depends on
current type (AC or DC) and freq. – 1 mA of AC at 60 Hz (1/1000 of an amp)– 5 mA for DC.
• High current can cause tissue damage or fibrillation (cardiac arrest)– 60 mA of AC (rms, 60 Hz) – 300–500 mA of DC
• AC at 120 V, 60 Hz is an especially dangerous because it usually exceeds the let-go threshold
• Seriousness of the shock depends on current path through the body Ohms law E=IR
11Aircraft Electrical Systems
Quiz time
• Electricity is the ‘flow’ of:a) Protonsb) Neutronsc) Electronsd) Klingons
12Aircraft Electrical Systems
Question 2
• In a DC circuit, the positive force used to make the current flow is often obtained from:a) Wall socketb) Batteryc) Alternator
13Aircraft Electrical Systems
Question 3
• To keep a battery from depleting its ‘charge’, rapidly (and perhaps burning up) each item to be powered must provide some form of electrical:a) Capacitanceb) Inductancec) Resistance
14Aircraft Electrical Systems
Question 4
• In a light bulb, the electrical resistance is in the form of the:a) Socketb) Filamentc) Glass enclosure
15Aircraft Electrical Systems
Question 5
• In an electrical circuit, the amount of electron flow is measured by the:a) Ammeterb) Voltmeterc) Loadmeter
16Aircraft Electrical Systems
Question 6
• The pressure of the electron flow is measured by the:a) Ammeterb) Voltmeterc) Dosimeterd) Parkingmeter
17Aircraft Electrical Systems
Question 7
• The purpose of a circuit breaker is to:a) Sense current that may be too high for the
circuit.b) Interrupt the flow of electricity to the ‘load’c) Protect the airplane’s electrical wiringd) Prevent an electrical fire
18Aircraft Electrical Systems
How much voltage does it take to kill a person?
a) 15,000 voltsb) 120 voltsc) While voltage may be a factor, as little as 30
ma of current can cause ventricular fibrillation..
19Aircraft Electrical Systems
What is a ‘short circuit’?
a) A direct path from a ‘ground’ to the positive source of power
b) A abnormal low resistance connection c) A possible destructive condition in an
electrical circuitd) All of the above
Aircraft Electrical Systems 20