Chapter 4 Electrical Systems Flashcards
Electrons flow from the ___ to the ___ side
Negative, positive
Electricity involves many terms that can be directly related to water plumbing. Voltage is comparable to, and can be thought of as, the ___ that pushes water through pipes. Current is the amount of ___ actually flowing through the pipes at any given time.
Pressure, Water
The greater the ___ (voltage) in a line, the greater the amount of ___ (electric current) that flows.
Water pressure, water
Using the water analogy, the alternator can be thought of as the ___ which provides water pressure to the ___ and the ___
Pump, primary bus, avionics bus
A spinning alternator causes electric ___ to flow into the primary bus and through the electrical equipment. It then returns to its ___ sources in a manner similar to the tray in our water analogy. This tray is called the ___.
Current, original, electrical ground
The electrical ground is not the ground upon which you stand. It’s usually the airplane’s …
metal frame
A load meter is located between the ___ and the ___ of our water (electrical) system.
Pump (alternator), primary bus
The load meter shows the ___ placed on the pump (alternator) by the airplane’s water (electrical) system.
water load (current)
A zero reading on the load meter (a full left deflection) means that the water pump (alternator) ___ providing pressure to the primary bus.
isn’t
A zero reading on the load meter means the alternator ___ providing electricity to the primary bus or there is ___ electrical current drawn by the airplane’s electrical equipment. This can happy when the ___ fails or all the airplane’s electrical equipment is turned off.
isn’t, no, alternator
Amps are a measure of ___ flow.
current
Circuit breakers protect electrical equipment and wires from receiving more ___ than they can safely handle
current
In the actual electrical system, the battery ___ stores the electrical charge provided by the alternator.
chemically
It’s the ___ which allows you to operate the airplane’s electrical equipment when the engine isn’t running or when the alternator fails in flight.
Battery
a 35 amp hour battery should (in theory) provide ___ amps of continuous current to the electrical system for one hour
35
While airplane batteries are rated at 12 or 24 volts, airplane electrical systems (their alternators) are rated for ___ or ___ volts.
14,28
Between the positive terminal of the battery and the primary bus is an ammeter, called a ___ ammeter.
Charge-discharge
As the name implies, the charge-discharge ammeter tells you if electrical current is flowing into or out of the ___
battery
A positive deflection of the charge-discharge ammeter usually implied that the battery is being…
charged
A negative needle deflection on the charge-discharge ammeter usually implies that the ___ is supplying the primary bus with electrical current
battery
Normally, the needle of the charge-discharge ammeter should be resting near the ___ or ___ mark. This implies that the battery is neither being charged nor discharged (a good sign)
zero, center
After startup, the battery is sure to be slightly drained. You can expect to see a ___ needle deflection of five, maybe sis or seven needle widths on the ammeter right after engine start
Positive (+)
Most airplane operation manuals suggest that after approximately ___ of cruising flight, the ammeter needle should return to within a two-needle-width deflection from center on the positive (+) or charging side.
30 minutes
Excess voltage resulting from a battery overcharge can ___ battery fluid (electrolyte), damaging the battery and possibly causing a battery
Boil off, fire
A needle deflection on the ___ side means current is flowing out of the battery onto the primary bus
negative (-)
Load meters provide impoartant indications about the health of the airplane’s electrical system. Unlike charge-discharge ammeters, they are calibrated to reflect the actual ___ load placed on the alternator
ampere
Load meters with a zero or full-left deflection indicate the alternator ___ providing current to the primary bus
isn’t
During flight with the electrical equipment in use, a full left deflection of the load meter needle is similar to a charge-discharge ammeter reading pointing to the ___ side of its scale.
negative (-)
A load meter needle deflection the the right of the zero index represents the ___ drain on the alternator.
electrical current
If you add all the electrical current used by the active electrical equipment, this sum should be equal to the amount of the load meter ___ deflection.
needle’s
Radios typically consume ___ amp(s) of current while receiving about ___ amp(s) while transmitting
one-half, 5
With two radios, two nav radios, one electric gyro, a transponder and an autopilot in use, a 16 amp deflection should be shown on the load meter. A needle deflection less than 16 amps implies that the ___ isn’t providing enough current to run the equipment
alternator
Load meter needle deflections less than the summed amperage of active and properly working electrical equipment imply that the ___ will eventually be ___.
Battery, drained
Supposed the load meter’s needle deflection is greater than the needs of the electrical equipment. This can lead to…
Evaporating battery fluid or battery and electrical fires
Voltage regulators or alternator control units (they’re essentially the same thing) regulate the ___ output
Alternator’s
Voltage regulators help alternators maintain a ___ voltage output under varying RPM conditions
Constant
Alternators need a little bit of electricity running through them before they’ll start producing electricity. This small amount of electrical prime is called the ___
Alternator field current
If your airplane has a low-voltage light, it can illuminate…
During low engine idle, and When the alternator has been taken offline
If your airplane has a high-voltage warning light, it can activate:
When the alternator puts out excessive voltage and if the voltage regulator malfunctions.
If you need the equipment that was disable by the popped circuit breaker, a good recommendation is to never reset the circuit breaker ___
More than one time
Manually taking the alternator offline becomes and important consideration if ___ condition occurs and the circuitry doesn’t ___ isolate the alternator.
An over voltage, automatically
If the battery is dead, the ___ isn’t going to work.
Alternator
If the voltage regulator goes bad and the alternator produces too much voltage, you can take the alternator offline by pulling the ___ circuit breaker
Main alternator
Turning off the alternator half of the mater switch on many airplanes will shut off the ___ field current flow, thus deactivating the ___
Alternator, alternator
If faced with an errant voltage regulator in flight which forces you to deactivate the alternator, unload the system by turning off ___ equipment
all nonessential electrical
