What does commutate mean?
Commutate is a technical verb used almost entirely within electrical engineering. It describes the periodic reversal of the direction of electric current — most famously accomplished inside DC motors and generators by a rotating mechanical switch called a commutator, whose carbon brushes transfer power between stationary and spinning parts. In modern usage the term extends beyond machinery: power-electronic circuits such as rectifiers and inverters are said to commutate current when they switch it between semiconductor devices to convert alternating current to direct current or vice versa. The word derives from Latin commutare, 'to change or exchange', sharing a root with 'commute' and 'mutable'. Because it belongs to specialist registers, 'commutate' seldom appears outside engineering texts, datasheets, and technical discussions, where its precise meaning — switching or reversing current — is essential rather than decorative.
verbTo reverse the direction of an electric current, especially by means of a commutator; more broadly, to convert alternating current into direct current (or perform the corresponding switching action) in an electrical machine.
- (of a machine or circuit) To reverse the direction of current flow periodically, as done by a commutator in DC machines.
- (electrical engineering, of power electronics) To switch current between devices or paths, e.g. in converters and inverters.
"The brushes and commutator work together to commutate the current in the armature windings."
"The motor's design ensures that each coil is properly commutated as it passes the brush gap."
"Modern inverters use semiconductor switches to commutate current far more efficiently than older mechanical systems."
Every time a DC motor spins smoothly instead of jerking to a halt, tiny brushes are 'commutating' — flipping the current dozens of times per second behind the scenes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of commutate
Commutate comes from Latin commutare, formed from com- ('together') plus mutare ('to change'), meaning 'to change utterly or interchange'. English adopted the word in the nineteenth century as engineers needed a term for the current-reversing action performed by the newly named 'commutator' in early electric motors. It thus shares its Latin root with 'commute', 'commutation', 'commutative' (a key term in mathematics), and ultimately 'mutable', 'mutant', and 'transmute'.
Related word forms
How commutate is actually used
Strictly technical vocabulary, found almost exclusively in electrical engineering literature and manuals on motors, generators, and power electronics. It is rare in general conversation and would be unfamiliar to most educated lay readers. The related noun 'commutator' and adjective 'commutative' are considerably better known than the verb itself.
Easily confused with commutate
'Commute' means to travel regularly between home and work or to exchange/ substitute one thing for another (as in commuting a sentence), while 'commutate' is a technical electrical-engineering term for reversing or converting current direction.