kilovolt-ampere
LowTechnical/Formal
Definition
Meaning
A unit of apparent electrical power, equal to one thousand volt-amperes, used primarily to rate the capacity of electrical equipment like transformers and generators.
It represents the total power (vector sum of real and reactive power) in an alternating current (AC) circuit. While kilowatts (kW) measure actual work done, kilovolt-amperes (kVA) measure the total power that must be supplied.
Linguistics
Semantic Notes
Crucially distinguishes between 'apparent power' (kVA) and 'real power' (kW). The ratio of kW to kVA is the power factor. Often used in specifications for equipment that must handle magnetic or capacitive loads.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or usage differences. Both use the term identically in electrical engineering contexts.
Connotations
Purely technical, with no regional connotative differences.
Frequency
Equally low-frequency in both dialects, confined to electrical engineering, power generation, and related industrial fields.
Vocabulary
Collocations
Grammar
Valency Patterns
The [equipment] is rated at [number] kVA.The [equipment] has a [number] kVA capacity.Vocabulary
Synonyms
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Used in procurement and specification documents for industrial equipment.
Academic
Taught in electrical engineering and physics courses dealing with AC circuit theory.
Everyday
Virtually never used in everyday conversation.
Technical
The primary context; used in design, specification, and analysis of electrical power systems.
Examples
By Part of Speech
adjective
British English
- The kVA rating is crucial for sizing the cable.
- We need a kVA-compliant generator.
American English
- The kVA rating determines the breaker size.
- Check the system's kVA requirements.
Examples
By CEFR Level
- The transformer has a big number on it for its power.
- The generator's power is shown in kilovolt-amperes.
- To select the correct uninterruptible power supply, you must know the load's required kilovolt-ampere rating.
- The discrepancy between the 500 kVA apparent power and the 400 kW real power output indicated a power factor of 0.8, necessitating corrective measures.
Learning
Memory Aids
Mnemonic
Think 'Kilo-Volt' and 'Ampere' – the two key electrical measurements multiplied together to get this unit of total apparent power.
Conceptual Metaphor
POTENTIAL FLOW: Electrical power as a measurable flow of potential (volt) and current (ampere).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'киловатт' (kilowatt). 'Килловольт-ампер' is the direct equivalent but the conceptual difference between apparent (kVA) and real (kW) power is critical.
Common Mistakes
- Using 'kilovolt-ampere' and 'kilowatt' interchangeably.
- Omitting the hyphen and writing as 'kilovolt ampere'.
- Incorrect pluralisation ('kilovolt-amperes' is standard).
Practice
Quiz
What does a kilovolt-ampere (kVA) primarily measure in an AC circuit?
FAQ
Frequently Asked Questions
kVA (kilovolt-ampere) measures apparent power—the total power in an AC system. kW (kilowatt) measures real power—the power that actually does useful work. The ratio (kW/kVA) is the power factor.
Equipment like transformers and generators must be sized to handle the total current flow, including the reactive (non-working) current. kVA rating reflects this total capacity, ensuring the equipment doesn't overheat from the magnetic or capacitive loads.
To convert kVA to kW, multiply the kVA value by the power factor (a number between 0 and 1). For example, 100 kVA with a power factor of 0.9 equals 90 kW. The exact power factor depends on the specific electrical load.
No, it is a highly specialised term. You will only encounter it in contexts related to electrical engineering, industrial power systems, and the specifications for large electrical appliances or backup power systems.