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1.What is electric traction?
ANS-Electric traction means using the
electric power for traction system (i.e. for railways,trams, trolleys etc).
Electric traction means
use of the electricity for all the above machines. Now a days,
magnetic traction is also
used for bullet trains.and basically dc motors are used for electric traction systems.
electric power for traction system (i.e. for railways,trams, trolleys etc).
Electric traction means
use of the electricity for all the above machines. Now a days,
magnetic traction is also
used for bullet trains.and basically dc motors are used for electric traction systems.
2.How
can you start-up
the 40w tube lite with 230v AC/DC
without using an choke/Coil?
can you start-up
the 40w tube lite with 230v AC/DC
without using an choke/Coil?
ANS-It’s possible by means of Electronic chokes,otherwise it’s not possible
to ionize the particles in tube light with normal voltage.
to ionize the particles in tube light with normal voltage.
3.What is “pu” in electrical engineering?
ANS-Pu stands for per unit and this will be used in single line diagram of power distribution and it is like a huge
electrical circuit with no of components (generators, transformers, loads) with
different ratings (in MVA and KV). To bring all the ratings into common
platform we use pu concept in which, in general largest MVA and KV ratings of the component is
considered as base values, then all other component ratings will get back into this basis.Those values are called as pu values.
(p.u=actual value/base value).
electrical circuit with no of components (generators, transformers, loads) with
different ratings (in MVA and KV). To bring all the ratings into common
platform we use pu concept in which, in general largest MVA and KV ratings of the component is
considered as base values, then all other component ratings will get back into this basis.Those values are called as pu values.
(p.u=actual value/base value).
4.Operation
carried out in Thermal power
stations?
carried out in Thermal power
stations?
ANS-The water is obtained in the boiler and
the coal is burnt so that steam is obtained this steam is allowed to hit the
turbine , the turbine which is coupled with the generator generates the
electricity.
the coal is burnt so that steam is obtained this steam is allowed to hit the
turbine , the turbine which is coupled with the generator generates the
electricity.
5.Why
link is provided
in neutral of an ac circuit and fuse in phase of ac circuit?
link is provided
in neutral of an ac circuit and fuse in phase of ac circuit?
ANS-Link is provided at a Neutral common
point in the circuit from which various connection are taken for the individual
control circuit and so it is given in a link form to withstand high Amps. But
in the case of Fuse in the Phase of AC circuit it is designed such that the
fuse rating is calculated for the particular circuit (i.e load) only.So if any
malfunction happen the fuse connected in the particular control circuit alone
will blow off.
point in the circuit from which various connection are taken for the individual
control circuit and so it is given in a link form to withstand high Amps. But
in the case of Fuse in the Phase of AC circuit it is designed such that the
fuse rating is calculated for the particular circuit (i.e load) only.So if any
malfunction happen the fuse connected in the particular control circuit alone
will blow off.
6.What is the difference between electronic
regulator and ordinary electrical rheostat regulator for fans?
regulator and ordinary electrical rheostat regulator for fans?
ANS-The difference between the electronic and
ordinary electrical regulator is that in electronic regulator power losses are
less because as we decrease the speed the electronic regulator gives the power
needed for that particular speed but in case of ordinary
rheostat type regulator, the power wastage
is same for every speed
and no power is saved.In electronic regulator, triac is employed for speed control
by varying the firing angle
speed and it is controlled but in rheostatic ,control resistance is
decreased by steps to achieve speed control.
ordinary electrical regulator is that in electronic regulator power losses are
less because as we decrease the speed the electronic regulator gives the power
needed for that particular speed but in case of ordinary
rheostat type regulator, the power wastage
is same for every speed
and no power is saved.In electronic regulator, triac is employed for speed control
by varying the firing angle
speed and it is controlled but in rheostatic ,control resistance is
decreased by steps to achieve speed control.
7.How tube light circuit is connected
and how it works?
and how it works?
ANS-A choke is connected in one end of the
tube light and a starter is in series with the circuit. When supply is provided
,the starter will interrupt the supply cycle of AC. Due to the sudden change of
supply the chock will generate around 1000volts . This volt will capable of to
break the electrons inside the tube to make electron flow. once the current
passes through the tube the starter circuit will be out of part. now there is
no change of supply causes choke voltage normalized and act as minimize the
current.
tube light and a starter is in series with the circuit. When supply is provided
,the starter will interrupt the supply cycle of AC. Due to the sudden change of
supply the chock will generate around 1000volts . This volt will capable of to
break the electrons inside the tube to make electron flow. once the current
passes through the tube the starter circuit will be out of part. now there is
no change of supply causes choke voltage normalized and act as minimize the
current.
8.whats is MARX
CIRCUIT?
CIRCUIT?
ANS-It is used with generators for charging a
number of capacitor in parallel and discharging them in series.It is used when
voltage required for testing is higher than the available.
number of capacitor in parallel and discharging them in series.It is used when
voltage required for testing is higher than the available.
9.What is encoder, how it function?
ANS-An encoder is a device used to change a
signal (such as a bitstream) or data into a code. The code may serve any of a
number of purposes such as compressing information for transmission or storage,
encrypting or adding redundancies to the input code, or translating from one
code to another. This is usually done by means of a programmed
algorithm,especially if any part is digital, while most analog encoding is done
with analog circuitry.
signal (such as a bitstream) or data into a code. The code may serve any of a
number of purposes such as compressing information for transmission or storage,
encrypting or adding redundancies to the input code, or translating from one
code to another. This is usually done by means of a programmed
algorithm,especially if any part is digital, while most analog encoding is done
with analog circuitry.
10.What are the advantages of speed control
using thyristor?
using thyristor?
ANS-Advantages :1. Fast Switching
Characterstics than Mosfet, BJT, IGBT 2. Low cost 3. Higher Accuray.
Characterstics than Mosfet, BJT, IGBT 2. Low cost 3. Higher Accuray.
11.Why Human body feel Electric
shock ?? n in an Electric train during running
, We did nt feel any Shock ?
why?
shock ?? n in an Electric train during running
, We did nt feel any Shock ?
why?
ANS-Unfortunately our body is a pretty good
conductor of electricity, The golden rule is Current takes the lowest resistant
path if you have insulation to our feet as the circuit is not complete (wearing
rubber footwear which doing some repairs is advisable as our footwear is a high
resistance path not much current flows through our body).The electric train is
well insulated from its electrical system.
conductor of electricity, The golden rule is Current takes the lowest resistant
path if you have insulation to our feet as the circuit is not complete (wearing
rubber footwear which doing some repairs is advisable as our footwear is a high
resistance path not much current flows through our body).The electric train is
well insulated from its electrical system.
12.what is the principle of motor?
ANS-Whenever a current carrying conductor is
placed in an magnetic field it produce turning or twisting movement is called
as torque.
placed in an magnetic field it produce turning or twisting movement is called
as torque.
13.Why, when birds sit on transmission lines
or current wires doesn’t get shock?
or current wires doesn’t get shock?
ANS-Its true that if birds touch the single
one line (phase or neutral) they don’t get electrical shock… if birds touch 2
lines than the circuit is closed and they get electrical shock.. so if a human
touch single one line(phase) then he doesn’t get shock if he is in the air (not
touching – standing on the ground if he is standing on the ground then touching
the line (phase) he will get a shock because the ground on what we standing is
like line (ground bed – like neutral)? and in the most of electric lines the
neutral is grounded..so that means that human who touch the line closes the
circuit between phase and neutral.
one line (phase or neutral) they don’t get electrical shock… if birds touch 2
lines than the circuit is closed and they get electrical shock.. so if a human
touch single one line(phase) then he doesn’t get shock if he is in the air (not
touching – standing on the ground if he is standing on the ground then touching
the line (phase) he will get a shock because the ground on what we standing is
like line (ground bed – like neutral)? and in the most of electric lines the
neutral is grounded..so that means that human who touch the line closes the
circuit between phase and neutral.
14.what is meant by armature reaction?
ANS-The effect of armature flu to main flux
is called armature reaction. The armature flux may support main flux or opposes
main flux.
is called armature reaction. The armature flux may support main flux or opposes
main flux.
15.what happen if we give 220 volts dc supply to d bulb r tube light?
ANS-Bulbs [devices] for AC are designed to
operate such that it offers high impedance to AC supply. Normally they have low
resistance. When DC supply is applied, due to low resistance, the current
through lamp would be so high that it may damage the bulb element.
operate such that it offers high impedance to AC supply. Normally they have low
resistance. When DC supply is applied, due to low resistance, the current
through lamp would be so high that it may damage the bulb element.
16.Which
motor has high Starting Torque
and Staring current
DC motor, Induction motor or Synchronous motor?
motor has high Starting Torque
and Staring current
DC motor, Induction motor or Synchronous motor?
ANS-DC Series motor has high starting torque.
We can not start the Induction motor and Synchronous motors on load, but can
not start the DC series motor without load.
We can not start the Induction motor and Synchronous motors on load, but can
not start the DC series motor without load.
17.what is ACSR cable and where we use it?
ANS-ACSR means Aluminium conductor steel
reinforced, this conductor is used in transmission & distribution.
reinforced, this conductor is used in transmission & distribution.
18.What is vaccum currcuit breaker.define with cause and where be use it Device?
ANS-breaker
is normally used to break
a ciruit. while
breaking the circuit,
the contact terminals will be separated. At the time of seperation an air gap
is formed in between the
terminals. Due to existing current
flow the air
in the gap is ionised and results in the arc. various mediums
are used to quench this arc in respective CB’s.
but in VCB the medium is
vaccum gas. since the air in the CB is having vaccum pressure the arc formation
is interrupted. VCB’s can be used upto kv.
is normally used to break
a ciruit. while
breaking the circuit,
the contact terminals will be separated. At the time of seperation an air gap
is formed in between the
terminals. Due to existing current
flow the air
in the gap is ionised and results in the arc. various mediums
are used to quench this arc in respective CB’s.
but in VCB the medium is
vaccum gas. since the air in the CB is having vaccum pressure the arc formation
is interrupted. VCB’s can be used upto kv.
19.What will happen when power factor is
leading
leading
ANS-in distribution of power? If their is high power factor, i.e if the power factor is close to one:
1.losses in form of heat will be reduced,
2.cable becomes less bulky and easy to carry, and very
cheap to afford
cheap to afford
3.it also reduces over heating of transformers.
20.whats the one main difference between UPS & inverter ? And electrical engineering & electronics engineering ?
ANS-.uninterrupt power supply is mainly use
for short time . means according to ups VA it gives backup. ups is also two
types : on line and offline . online ups having high volt and amp for long time
backup with with high dc voltage.but ups start with 2v dc with 7 amp. but
inverter is startwith 2v,24,dc to 36v dc and 20amp to 80amp battery with long
time backup.
for short time . means according to ups VA it gives backup. ups is also two
types : on line and offline . online ups having high volt and amp for long time
backup with with high dc voltage.but ups start with 2v dc with 7 amp. but
inverter is startwith 2v,24,dc to 36v dc and 20amp to 80amp battery with long
time backup.
21.What is 2 phase motor?
ANS- two phase motor is a motor with the the
starting winding and the running winding have a phase split. e.g;ac servo
motor.where the auxiliary winding and the control winding have a phase split of
90 degree.
starting winding and the running winding have a phase split. e.g;ac servo
motor.where the auxiliary winding and the control winding have a phase split of
90 degree.
