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SSC JE General Engineering (Electrical) Flashcards
51 question-and-answer cards covering General Engineering (Electrical) as it is examined in SSC JE. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the General Engineering (Electrical) deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
What is the operating principle of a PMMC (Permanent Magnet Moving Coil) instrument and what does it measure?
It works on the motor principle—a current-carrying coil in a permanent magnetic field experiences a torque. It measures only DC, has a uniform (linear) scale, and is used with rectifiers/shunts for other ranges.
How is a galvanometer converted into an ammeter and into a voltmeter?
Into an ammeter: connect a low-resistance shunt in parallel. Into a voltmeter: connect a high-resistance multiplier in series.
What does a wattmeter measure and what is the basic operating type used?
A wattmeter measures electrical power (watts). The common type is the electrodynamometer (dynamometer) wattmeter, having a fixed current coil and a moving voltage (pressure) coil; deflection ∝ VI cos φ.
What is the working principle of an energy meter (induction type)?
It works on the induction principle: interacting fluxes from current and voltage coils induce eddy currents in an aluminium disc, producing torque that rotates the disc at a speed proportional to power; the number of revolutions measures energy (kWh).
What is a Wheatstone bridge used for and the balance condition?
It measures unknown resistance. At balance (no galvanometer current), P/Q = R/S, i.e., the products of opposite arms are equal: P·S = Q·R.
State the EMF equation of a DC generator.
Eg = (PΦZN)/(60A) volts, where P = poles, Φ = flux per pole, Z = total armature conductors, N = speed in rpm, A = number of parallel paths.
What is back EMF in a DC motor and why is it important?
Back EMF (Eb = PΦZN/60A) is the EMF induced in the armature that opposes the supply voltage. It regulates armature current automatically: Ia = (V - Eb)/Ra, and makes the motor self-regulating with load.
How are DC machines classified based on field excitation?
Separately excited (field from external source) and self-excited; self-excited types are series-wound, shunt-wound, and compound-wound (further long/short shunt, cumulative/differential).
State the torque equation of a DC motor.
Armature torque Ta = (PΦZIa)/(2πA) N·m, i.e., torque is proportional to flux and armature current (Ta ∝ Φ·Ia).
What is the EMF equation of a transformer?
E = 4.44 f N Φmax volts, where f = frequency, N = number of turns, and Φmax = maximum flux. The turns ratio E1/E2 = N1/N2 = I2/I1.
What are the two main losses in a transformer and how do they vary?
Core (iron) losses—hysteresis and eddy current—are constant and independent of load. Copper losses (I²R) are variable and proportional to the square of load current. Maximum efficiency occurs when copper loss = iron loss.
What is the working principle of a three-phase induction motor and slip?
A rotating magnetic field produced by 3-phase stator currents induces currents in the rotor (transformer action), producing torque. Slip s = (Ns - N)/Ns, the fractional difference between synchronous speed and rotor speed.
Give the formula for synchronous speed of an AC machine.
Ns = 120f/P rpm, where f is supply frequency in Hz and P is the number of poles.
Why is a synchronous motor not self-starting, and how is it started?
At standstill the rotor cannot follow the rapidly rotating stator field, so net average torque is zero. It is started using damper (amortisseur) windings as an induction motor, or by an auxiliary/pony motor, then synchronized.
What is the effect of varying excitation in a synchronous motor (V-curves)?
At constant load, under-excitation makes the motor draw lagging current, over-excitation makes it draw leading current, and normal excitation gives unity power factor (minimum armature current). Plotting Ia vs field current gives V-curves.
What is a synchronous condenser?
An over-excited synchronous motor running on no load, used to supply leading reactive power (VAR) for power factor improvement and voltage control in power systems.
What is voltage regulation of an alternator (synchronous generator)?
It is the rise in terminal voltage when full load is removed (field excitation and speed constant), expressed as a percentage: %Reg = [(E - V)/V] × 100, where E is no-load EMF and V is full-load terminal voltage.
Differentiate base load and peak load power plants.
Base load plants (e.g., thermal, nuclear, large hydro) supply the constant minimum demand continuously at high load factor. Peak load plants (e.g., gas turbines, pumped storage, diesel) supply short-duration peak demand and start/stop quickly.
Why is power transmitted at high voltage over long distances?
For a given power, higher voltage means lower current, which reduces I²R line losses and voltage drop, allows thinner conductors, and improves transmission efficiency.
Why is electrical power generated and transmitted as three-phase AC rather than DC or single-phase?
Three-phase AC enables easy voltage transformation, gives constant power, requires less conductor material than single-phase for the same power, and produces a rotating magnetic field for motors. AC is easily stepped up/down by transformers.
Define load factor and diversity factor.
Load factor = average load / maximum demand (over a period); higher is more economical. Diversity factor = sum of individual maximum demands / maximum demand of the whole system (always ≥1).
What methods of electric heating use induced/eddy currents and dielectric loss?
Induction heating heats conducting materials via eddy currents induced by an alternating magnetic field. Dielectric heating heats insulating materials by molecular friction from a high-frequency alternating electric field.
What is the ideal speed-time curve / important requirement for traction motors, and which motor is preferred for DC traction?
Traction needs high starting torque and good speed control. The DC series motor is preferred because it provides high starting torque, automatically reduces speed on heavy load, and is self-regulating (Ta ∝ Ia²).
Differentiate intrinsic and extrinsic semiconductors, and N-type vs P-type doping.
Intrinsic = pure semiconductor (e.g., Si, Ge). Extrinsic = doped. N-type is doped with pentavalent atoms (electrons are majority carriers); P-type is doped with trivalent atoms (holes are majority carriers).
What this deck covers
The General Engineering (Electrical) deck follows the SSC JE General Engineering (Electrical) syllabus — 11 chapters and 23 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 4.6 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 189 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
General Engineering (Electrical) flashcards FAQ
How many General Engineering (Electrical) flashcards are in this SSC JE deck?
51 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these SSC JE flashcards free?
Yes. The preview here is free to read with no signup, and the full 51-card deck is free inside the Examius app.
What do the General Engineering (Electrical) cards cover?
They follow the SSC JE General Engineering (Electrical) syllabus — 11 chapters and 23 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.