field coil
LowTechnical
Definition
Meaning
An electromagnetic coil that generates a magnetic field in electrical machinery, such as motors, generators, or loudspeakers.
The term can refer more broadly to any coil whose primary function is to establish a magnetic field in an electromechanical device.
Linguistics
Semantic Notes
A 'field coil' is distinct from an 'armature coil'; the former creates the stationary magnetic field, while the latter interacts with it.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Spelling conventions for related terms may differ (e.g., 'metre' vs. 'meter' for measuring wavelength).
Connotations
Purely technical with identical connotations in both dialects.
Frequency
Identically low in both, confined to engineering, physics, and electronics contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
The [device] has a field coil.The field coil [is energized/fails].A [shunt/series] field coil provides excitation.Vocabulary
Synonyms
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Rare, only in manufacturing or procurement contexts for industrial motors.
Academic
Used in engineering and physics textbooks, lab manuals, and research papers.
Everyday
Virtually never used.
Technical
Core term in electrical engineering, motor repair, and electronics design.
Examples
By Part of Speech
adjective
British English
- The field-coil excitation was faulty.
- We need a field-coil resistance test.
American English
- The field coil assembly failed.
- Check the field coil resistance.
Examples
By CEFR Level
- A field coil is a part of some electric motors.
- The technician diagnosed the problem as a burnt-out field coil in the generator.
- In a DC motor, the field coil creates the stationary magnetic field.
- The design utilises a separately energised shunt field coil to allow for precise speed control of the motor.
- To troubleshoot, first measure the continuity across the field coil terminals to rule out an open circuit.
Learning
Memory Aids
Mnemonic
Imagine a sports field (field) with a coiled snake in the centre. The snake (coil) creates the 'atmosphere' (magnetic field) for the game.
Conceptual Metaphor
THE GENERATOR IS A PUMP; the field coil is the 'priming mechanism' that creates the pressure (magnetic field) to move electrons.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid direct translation 'полевая катушка' which sounds strange; use the established term 'обмотка возбуждения' or 'катушка возбуждения'.
- Do not confuse with 'field of view' ('поле зрения') or agricultural field.
Common Mistakes
- Confusing 'field coil' with 'armature coil'.
- Using 'field coil' to describe a coil in a general field (e.g., magnetic field coil is redundant).
Practice
Quiz
What is the primary function of a field coil?
FAQ
Frequently Asked Questions
It can be designed for either, but classic DC motors and generators typically use DC field coils. AC field coils are used in some synchronous motors and alternators.
Inside older or industrial DC electric motors, generators (alternators), some types of loudspeakers (field coil speakers), and electromagnetic relays.
The device loses its magnetic field. A motor won't start or will run weakly; a generator won't produce voltage; a loudspeaker won't work.
A field coil requires an electrical current to create a magnetic field (electromagnet), which can be controlled. A permanent magnet creates a fixed field without power.