The capacity of an accumulator is ? Study > Manual
The quantity of electricity that battery can supply during discharge.
a battery's capacity the quantity of electricity that it can supply during discharge the more electrolyte electrode material there in cell greater capacity of cell
a small cell has less capacity than a larger cell with same chemistry they develop same open circuit voltage
because of chemical reactions within cells capacity of a battery depends on discharge conditions such as magnitude of current (which may vary with time) allowable terminal voltage of battery temperature other factors the available capacity of a battery depends upon rate at which it discharged if a battery discharged at a relatively high rate available capacity will be lower than expected.
The moving part in an AC generator is usually referred to as the ?
The moving part in an ac generator usually referred to as The quantity of electricity that battery can supply during discharge.
a battery's capacity the quantity of electricity that it can supply during discharge the more electrolyte electrode material there in cell greater capacity of cell
a small cell has less capacity than a larger cell with same chemistry they develop same open circuit voltage
because of chemical reactions within cells capacity of a battery depends on discharge conditions such as magnitude of current (which may vary with time) allowable terminal voltage of battery temperature other factors the available capacity of a battery depends upon rate at which it discharged if a battery discharged at a relatively high rate available capacity will be lower than expected.
The purpose of bonding the metallic parts of an aircraft is to ?
The purpose of bonding metallic parts of an aircraft to Provide safe distribution of electrical charges currents.
the single earth return uses aircraft structure as a return path if component not electrical it does not need a return path but still requires bonding to equalise potential difference in event of static build up this why answer provide a single earth electrical devices false. A constant speed drive aims at ensuring That electric generator produces a constant frequency.
the single earth return uses aircraft structure as a return path if component not electrical it does not need a return path but still requires bonding to equalise potential difference in event of static build up this why answer provide a single earth electrical devices false. When a persistent underexcitation fault detected on an ac generator connected to aircraft mains with another ac generator protection device opens The exciter control relay generator breaker the tie breaker. A control relay a 'magnetic switch' which can isolate a circuit so in effect same as a 'breaker' an 'exciter breaker' an 'exciter control relay' are in effect same thing
an exciter breaker (exciter control relay) will isolate power to voltage regulator
the generator breaker will isolate generator from bus bar
the tie breaker will isolate two different bus bars from each other or can connect two generators to same bus bar
in most cases you will want to keep bus bars connected so that you can use all your services so you will trip generator breaker to isolate generator from bus bar the exciter breaker so you effectively shut down that generator
if you have 2 generators supplying same single bus bar then you will trip tie breaker to isolate generator the generator exciter breakers to isolate shut down generator. A test to assess state of charge of a lead acid battery would involve Comparing 'on loa 'off loa battery voltages. A control relay a 'magnetic switch' which can isolate a circuit so in effect same as a 'breaker' an 'exciter breaker' an 'exciter control relay' are in effect same thing
an exciter breaker (exciter control relay) will isolate power to voltage regulator
the generator breaker will isolate generator from bus bar
the tie breaker will isolate two different bus bars from each other or can connect two generators to same bus bar
in most cases you will want to keep bus bars connected so that you can use all your services so you will trip generator breaker to isolate generator from bus bar the exciter breaker so you effectively shut down that generator
if you have 2 generators supplying same single bus bar then you will trip tie breaker to isolate generator the generator exciter breakers to isolate shut down generator. The advantages of grounding negative pole of aircraft structure are 1 weight saving 2 easy fault detection 3 increase of short circuit risk 4 reduction of short circuit risk 5 circuits are not single wired lines the combination regrouping all correct statements Comparing 'on loa 'off loa battery voltages.
the fuselage used as an earth return electrical components on an aircraft which means that you only need one length of cable (the battery will be connected its negative pole) this saves weight space as you don't need two cables to complete a circuit
statement 3 increase of short circuit risk not an advantage statement 5 circuits are not single wired lines wrong
correct answer '1 2 4' the most correct one even if we are not totally agree with. 8 When an 'open circuit' occurs in an electrical supply system Loss of continuity will prevent its working components from functioning.
short circuit (open circuit) fault as most common failure of aircraft electrical power supply system when an 'open circuit' occurs components connected on circuit cease to operate. 9 An ac generator driven a csd unit Requires a voltage controller to maintain constant voltage under load. The csd (constant speed drive) a hydro mechanical unit fitted between engine gearbox the generator its function to maintain a constant generator speed regardless of engine speed
for a three phase generator to maintain 400hz this would be 8000 rpm although generator speed remains constant electrical load will vary according to services selected to maintain a steady output voltage strength of field (excitation) controlled the voltage regulator. 10 Consider variable pitch propeller of a turbo prop during deceleration When braking propeller supplies negative thrust absorbs engine power. when braking it means when you move power lever in reverse or beta range
in 'reverse' pitch position engine/propeller turns in same direction as in normal (forward) pitch position but propeller blade angle positioned to other side of flat pitch in reverse pitch air pushed away from airplane rather than being drawn over it reverse pitch results in braking action rather than forward thrust of airplane. 11 The correct formula to calculate total displacement of a multi cylinder piston engine the Piston area x piston stroke x number of cylinders. when braking it means when you move power lever in reverse or beta range
in 'reverse' pitch position engine/propeller turns in same direction as in normal (forward) pitch position but propeller blade angle positioned to other side of flat pitch in reverse pitch air pushed away from airplane rather than being drawn over it reverse pitch results in braking action rather than forward thrust of airplane. 12 When changing power on engines equipped with constant speed propeller engine overload avoided Increasing rpm before increasing manifold pressure. A small trick
propeller´s control the bravest
the first to enter (increase rpm before increase map) the last to leave (decrease map before decrease rpm. 13 The blade angle of a constant speed propeller Increases with increasing true air speed. When it refers to blade angle it refers to angle between chord line the direction of propeller rotation
the important bit in this question that it a constant speed prop you are correct in that angle of attack does decrease as forward speed increases so thrust decreases as well
therefore rpm would increase csu would sense increase in rpm would then increase blade angle to reduce rpm down to correct speed restore lost thrust. 14 A propeller blade twisted so as to Keep local angle of attack constant along blade. The angle of attack the angle between blade chord line the relative airflow trouble is relative airflow different along blade the blade rotating so bit nearest hub has a small speed at right angles to way aircraft going but bit near tip moving rapidly across aircraft flight path
to put real numbers on to this a 10 ft blade doing 3000rpm will have a tip speed of about 300mph so if aircraft going forward at 300mph relative airflow hitting tip at 45deg off aircraft centre line
thus if you want tip to have same angle of attack as root you have to twist blade 45deg along its length
the speed past tip will now be more like 440mph in total so if angle of attack the chord length were same you would get a lot more lift (thrust) out toward tip
but only reason why you might not want extra thrust because it might bend blade and if that worries you you can taper blade reducing chord length
blade design always a compromise but if you want best efficiency (least fuel consumption) in cruise you will twist blade so all sections reach their most efficient angle of attack at same time. 15 A pilot can actuate feathering system Pulling propeller control lever rearwards.
by pulling propeller control lever fully rearwards you will feather propeller (to minimize drag in event of an engine failure example) in normal flight you will pull or push propeller control lever to adjust blade pitch the different phases of flight (climb cruise descent)
. 16 When increasing true airspeed with a constant engine rpm angle of attack of a fixed pitch propeller Pulling propeller control lever rearwards. With fixed propellers throttle controls rpm
variations in forward speed affect angle of attack which varies in line with amount of airflow into propeller disc if you increase speed angle of attack reduces if you slow down it increases affecting lift/drag ratio meaning that a fixed pitch propeller gets less efficient as you move away from its optimum speed which usually set cruise. 17 A pressure relief valve in an oil system that does not seat correctly could result in Pulling propeller control lever rearwards. To prevent too high a pressure a pressure release valve (prv) fitted it comprises a stainless steel ball bearing a spring
the ball forced the spring against an oil port when oil pressure sufficiently high ball if forced off its seat oil allowed to bypass this restriction thus making sure that pressure never gets too high
if pressure relief valve not hermetic there will be a leak the pressure decreases. 18 In case of engine failure during flight blades of a constant speed propeller in a single engine aeroplane not fitted with feathering system Move in lowest pitch position the centrifugal force and/or spring force. In event of a problem causing engine to stop propeller goes to minimum pitch in order to reduce drag permits pilot to try to restart engine(if possible) with less drag you will have less propeller torque allowing a windmilling start a constant speed propeller system will make use of centrifugal force oil or gas pressure or a spring to reduce pitch. 19 For take off correct combination of propeller pitch 1 and propeller lever position 2 at brake release Move in lowest pitch position the centrifugal force and/or spring force. Pushing propeller control lever fully forward selects max rpm in order to achieve this propeller goes to a fine pitch this also called low pitch! high pitch would be a coarse pitch position
. 20 For piston engines mixture ratio the ratio between Mass of fuel mass of air entering cylinder. Pushing propeller control lever fully forward selects max rpm in order to achieve this propeller goes to a fine pitch this also called low pitch! high pitch would be a coarse pitch position
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