counter electromotive force: meaning, definition, pronunciation and examples
C2Technical, Academic
Quick answer
What does “counter electromotive force” mean?
A voltage generated within an electrical motor or generator that opposes the supply voltage, thereby regulating current flow.
Audio
Pronunciation
Definition
Meaning and Definition
A voltage generated within an electrical motor or generator that opposes the supply voltage, thereby regulating current flow.
In physics and electrical engineering, the electromotive force (EMF) induced in a motor armature due to its rotation in a magnetic field, which acts against the applied voltage and limits the armature current.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Spelling conventions follow the general UK/US patterns for other compound terms (e.g., 'counter-electromotive force' with a hyphen is sometimes seen in UK technical writing, but the open form is standard).
Connotations
Identical technical meaning and connotation in both varieties.
Frequency
Exclusively used in technical contexts (electrical engineering, physics) with identical frequency in both regions.
Grammar
How to Use “counter electromotive force” in a Sentence
The [motor] generates a significant counter electromotive force.Counter electromotive force is [proportional/opposed] to [speed/armature current].Vocabulary
Collocations
Examples
Examples of “counter electromotive force” in a Sentence
verb
British English
- The armature counter-electromotives as it rotates.
- The motor is counter-electromotiving against the supply.
American English
- The winding counter-electromotives under load.
- The generator began to counter-electromotive.
adverb
British English
- The voltage reacted counter-electromotively.
- The system functioned counter-electromotively.
American English
- The current was reduced counter-electromotively.
- It operated counter-electromotively to stabilise the circuit.
adjective
British English
- The counter-electromotive effect was significant.
- We measured the counter-electromotive voltage.
American English
- The counter-electromotive response limits the current.
- A strong counter-electromotive field was present.
Usage
Meaning in Context
Business
Rare, except in technical sales or specifications for electric motors and drives.
Academic
Core term in physics and electrical engineering courses, textbooks, and research papers on motor theory.
Everyday
Virtually never used in everyday conversation.
Technical
Standard term in design, analysis, and troubleshooting of electric machines, motor controllers, and inductive circuits.
Vocabulary
Synonyms of “counter electromotive force”
Vocabulary
Antonyms of “counter electromotive force”
Watch out
Common Mistakes When Using “counter electromotive force”
- Pronouncing 'electromotive' as 'electro-motive' (four syllables) instead of the correct five (e-lec-tro-mo-tive).
- Confusing it with 'back current' instead of 'back voltage'.
- Using 'counter-electromotive force' as a verb.
FAQ
Frequently Asked Questions
No. Resistance opposes current uniformly and dissipates energy as heat. Counter EMF opposes the applied voltage in a speed-dependent manner and is a fundamental part of energy conversion in motors/generators.
It provides a natural feedback signal proportional to motor speed. This principle is used in sensorless speed control algorithms and is crucial for understanding motor behaviour under load.
Yes. When a motor's power is suddenly disconnected, the collapsing magnetic field can induce a very high counter EMF (voltage spike) that can damage electronic components, necessitating protective circuits like flyback diodes.
Yes, the concept is analogous. In AC induction motors, it is often discussed in terms of 'back EMF' or the voltage induced in the stator by the rotor's rotating magnetic field, affecting the current drawn from the supply.
A voltage generated within an electrical motor or generator that opposes the supply voltage, thereby regulating current flow.
Counter electromotive force is usually technical, academic in register.
Counter electromotive force: in British English it is pronounced /ˌkaʊntər ɪˌlɛktrəʊˈməʊtɪv fɔːs/, and in American English it is pronounced /ˌkaʊn(t)ər ɪˌlɛktroʊˈmoʊdɪv fɔːrs/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “No common idioms exist for this technical term.”
Learning
Memory Aids
Mnemonic
Imagine a motor as a stubborn donkey. The voltage you apply tries to make it run (electromotive force), but as it speeds up, it generates its own kick-back force (counter electromotive force) that says 'slow down!'
Conceptual Metaphor
A REGULATOR or GOVERNOR; a natural, self-induced braking force that maintains balance.
Practice
Quiz
What is the primary function of counter electromotive force in a DC motor?