UPRVUNL AE key terms

The ratio of real power (kW) actually consumed to apparent power (kVA) supplied; a low value means more current flows for the same useful work, raising losses and billing penalties.

Power that oscillates between source and inductive or capacitive loads without doing useful work, measured in kVAR; it is needed to sustain magnetic fields in motors and transformers.

Average load over a period divided by the peak load in that period; a higher figure means plant and equipment are used more evenly and generation cost per unit falls.

The ratio of the sum of individual maximum demands of consumers to the maximum demand of the whole system; it is always greater than one and reduces required installed capacity.

A group of shunt-connected capacitors used to supply reactive power locally, correcting a lagging power factor and relieving the supply system of reactive current.

A switching device that makes, carries and interrupts fault current automatically, extinguishing the arc between its contacts so the circuit can be opened safely under load.

A sensing device that detects abnormal current, voltage, frequency or temperature and sends a trip signal to a circuit breaker to isolate the faulty section.

A scheme that compares currents entering and leaving a protected zone; any difference indicates an internal fault and triggers tripping, giving fast and selective protection for transformers and generators.

An instrument transformer that steps high line current down to a standard low value for meters and relays, while insulating the measuring circuit from the high-voltage line.

Deliberate connection of exposed metalwork or a neutral point to the ground so fault current has a low-resistance path, limiting touch voltage and enabling protective devices to operate.

The resistance offered by insulation between conductors or between a conductor and earth, measured with a megger; a falling value warns of moisture, ageing or impending failure.

Refined mineral oil used in transformers for insulation and heat transfer; its dielectric strength and moisture content are periodically tested to confirm the unit remains safe.

A gas-actuated protective device fitted in the pipe between a transformer tank and conservator; it alarms on slow gas accumulation and trips on violent oil surge caused by an internal fault.

The ideal thermodynamic cycle for steam power plants, comprising pump, boiler, turbine and condenser processes; its efficiency sets the benchmark for coal-based generation.

Raising steam temperature above its saturation value at the same pressure before it enters the turbine, which increases cycle efficiency and reduces blade erosion from wetness.

The sub-atmospheric pressure maintained in a steam condenser so exhaust steam expands further and does more work; poor vacuum directly reduces turbine output and efficiency.

Ratio of heat usefully absorbed by steam to heat released by fuel combustion, commonly found by indirect (heat loss) method accounting for dry flue gas, moisture and unburnt losses.

Air supplied beyond the theoretical stoichiometric quantity needed for complete combustion; too little causes unburnt fuel loss, too much carries heat away in the flue gas.

The small designed gap between a shaft and its bearing surface that allows an oil film to form; incorrect clearance causes overheating, vibration or seizure in rotating machines.

Continuous or periodic measurement of vibration, temperature, oil debris and noise on running plant to detect developing faults early and plan maintenance before breakdown occurs.

A high-gain differential amplifier used with feedback networks to perform addition, subtraction, integration, filtering and comparison; ideal behaviour assumes infinite gain and input impedance.

Returning a fraction of the output signal to the input; negative feedback stabilises gain and widens bandwidth, while positive feedback produces oscillation or latching behaviour.

The smallest voltage change a converter can distinguish, set by its bit count and reference voltage; an n-bit ADC divides the full range into 2^n steps.

A device converting one form of energy into another, such as pressure into an electrical signal, forming the first element of any measurement or control loop.

Comparing an instrument's reading against a traceable standard and adjusting it so errors stay within permitted limits, usually recorded as a certificate valid for a stated period.

The mass of water divided by mass of cement in a concrete mix; it governs strength and durability, with lower values giving stronger but less workable concrete.

The ease with which fresh concrete can be mixed, placed and compacted without segregation; commonly assessed by slump, compaction factor or vee-bee tests.

Keeping concrete moist and at a suitable temperature after placing so cement hydration continues, developing design strength and reducing shrinkage cracking.

The internal moment at a section of a beam equal to the algebraic sum of moments of all forces on one side of that section; it produces bending stress across the depth.

The internal force at a beam section equal to the algebraic sum of transverse forces on one side; its variation along the span defines shear reinforcement requirements.

A sequence following a hidden rule such as constant difference, ratio, squares or alternating operations; the task is to identify the rule and supply the missing term.

A reasoning item where letters or words are transformed by a fixed rule, such as shifting positions or reversing order, and the candidate must apply the same rule to a new word.

A pair-based reasoning item testing the relationship between two items, such as worker and tool or cause and effect, which must then be matched in a second pair.

A logic item presenting statements about categories and asking which conclusions necessarily follow, solved by drawing set diagrams or applying standard validity rules.

A reasoning problem describing family links through sentences or symbols, requiring the candidate to trace relationships and identify how two persons are related.

A problem tracking a person's path through turns and distances, asking for final direction, net displacement or straight-line distance from the start point.

Counting methods where permutation treats order as important and combination treats it as irrelevant; choosing the right one is essential for arrangement and selection problems.

The ratio of favourable outcomes to total equally likely outcomes in a sample space, used for dice, cards, balls and selection problems in aptitude tests.

Aptitude problems relating rate of work, number of workers and days taken, solved by converting each worker's output to a per-day fraction of the total job.

A variant of time-and-work problems where inlet pipes fill and outlet pipes empty a tank; rates are added or subtracted to find net filling time.

Interest computed only on principal (simple) versus on principal plus accumulated interest (compound); compound growth follows a power law over the number of periods.

A fraction expressed per hundred, used to compare quantities and forming the base of profit-loss, discount, interest and data-interpretation calculations.

System software that manages hardware, memory, files and processes and provides services to application programs; examples include Windows, Linux and Unix variants.

Volatile read-write memory holding programs and data currently in use; its contents are lost when power is removed, unlike ROM or secondary storage.

Hardware or software that filters network traffic against rules, blocking unauthorised access while permitting approved communication between networks or hosts.

In Hindi grammar, the joining of two adjacent sounds or words where the ending and beginning modify into a combined form, classified as swar, vyanjan or visarga sandhi.

A Hindi compound word formed by merging two or more words into one unit, with types such as tatpurush, dvandva, bahuvrihi and dvigu determined by the relation between members.

A Hindi prefix particle placed before a root word that modifies or intensifies its meaning, such as anu, prati, vi and sam.

A fixed English expression whose meaning cannot be derived from its individual words; questions ask for the correct meaning or a suitable one-word substitute.

Vocabulary items asking for a word of similar meaning or of opposite meaning to a given word; accuracy depends on knowing the word's exact sense in context.

A grammar item in which a sentence is divided into parts and the candidate identifies the part containing a grammatical mistake such as wrong tense, preposition or agreement.

The rule that a verb must match its subject in number and person, with special cases for collective nouns, indefinite pronouns and phrases inserted between subject and verb.