motor

View more Technology videos

A machine that converts electrical into mechanical energy. Motors that develop rotational mechanical motion are most common, but linear motors are also used. A rotary motor delivers mechanical power by means of a rotating shaft extending from one or both ends of its enclosure (see illustration). The shaft is attached internally to the rotor. Shaft bearings permit the rotor to turn freely. The rotor is mounted coaxially with the stationary part, or stator, of the motor. The small space between the rotor and stator is called the air gap, even though fluids other than air may fill this gap in certain applications.

Cutaway view of a single-phase induction motor. (Emerson Motor Division)

In a motor, practically all of the electromechanical energy conversion takes place in the air gap. Commercial motors employ magnetic fields as the energy link between the electrical input and the mechanical output. The air-gap magnetic field is set up by current-carrying windings located in the rotor or the stator, or by a combination of windings and permanent magnets. The magnetic field exerts forces between the rotor and stator to produce the mechanical shaft torque; at the same time, in accord with Faraday's law, the magnetic field induces voltages in the windings. The voltage induced in the winding connected to the electrical energy source is often called a countervoltage because it is in opposition to the source voltage. By its magnitude and, in the case of alternating-current (ac) motors, its phase angle, the countervoltage controls the flow of current into the motor's electrical terminals and hence the electrical power input. The physical phenomena underlying motor operation are such that the power input is adjusted automatically to meet the requirements of the mechanical load on the shaft. See also Electromagnetic induction; Magnet; Windings in electric machinery.

Both the rotor and stator have a cylindrical core of ferromagnetic material, usually steel. The parts of the core that are subjected to alternating magnetic flux are built up of thin steel laminations that are electrically insulated from each other to impede the flow of eddy currents, which would otherwise greatly reduce motor efficiency. The windings consist of coils of insulated copper or aluminum wire or, in some cases, heavy, rigid insulated conductors. The coils may be placed around pole pieces, called salient poles, projecting into the air gap from one of the cores, or they may be embedded in radial slots cut into the core surface facing the air gap. In a slotted core, the core material remaining between the slots is in the form of teeth, which should not be confused with magnetic poles. See also Eddy current.

Direct-current (dc) motors usually have salient poles on the stator and slotted rotors. Polyphase ac synchronous motors usually have salient poles on the rotor and slotted stators. Rotors and stators are both slotted in induction motors. Permanent magnets may be inserted into salient pole pieces, or they may be cemented to the core surface to form the salient poles.

The windings and permanent magnets produce magnetic poles on the rotor and stator surfaces facing each other across the air gap. If a motor is to develop torque, the number of rotor poles must equal the number of stator poles, andthis number must be even because the poles on either member must alternate inpolarity (north, south, north, south) circularly around the airgap.

---

verb

To run and control (a motor vehicle): drive, pilot, wheel. Slang tool. See move/halt.

A machine which converts electric power into mechanical power by means of a rotating shaft.

---

Pertaining to or connected with movements produced by muscle actions.

in. to depart.  Well, let's motor, you guys. It's getting late.

---

IN BRIEF: n. - Machine that converts other forms of energy into mechanical energy and so imparts motion; A nonspecific agent that imparts motion v. - Travel or be transported in a vehicle adj. - Causing or able to cause motion.

Getting angry can sometimes be like leaping into a wonderful responsive sports car, gunning the motor, taking off at high speed and then discovering the brakes are out of order. — Maggie Scarf

LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!

(in biology) pertaining to movement of an organ or part; pertaining to nerves or neurons involved in muscular activity.

Previous:	motilin, motile, motif
Next:	motor protein, mould, moult

1. pertaining to motion.
2. a muscle, nerve or center that effects movements.

• m. activity — limb movement the most obvious of these forms of activity.
• m. alpha-neuron — ventral spinal cord neurons which innervate skeletal muscle. Called also final common pathway, lower motor neuron.
• m. depressant anticonvulsant — a drug that depresses motor activity and hence prevents convulsions, e.g. phenobarbital sodium, phenytoin sodium.
• m. dysfunction — abnormality of the motor system.
• m. end-plate — sites of neuraptic transmission of acetylcholine from nerve to muscle receptors.
• m. fibers — innervate the body effectors.
• m. lubricating oil — ingestion may cause lead poisoning.
• m. nerve conduction — the transmission of impulses along motor nerves to skeletal muscle.
• m. unit — includes the motor neuron, neuromuscular junction, and the myofibrils innervated by the neuron.
• m. unit action potential — the electrical activity of voluntary muscle contractions recorded by needle electromyography.

n

Pertaining to a muscle, nerve, or center that produces or affects movement.

For a list of words related to motoring, see:

• Travel and Tourism - motoring: vacation or travel by automobile

---

See words rhyming with "motor."

  See crossword solutions for the clue Motor.

Dansk (Danish)
n. - motor, drivkraft
adj. - bevæge-
v. intr. - blive kørt
v. tr. - køre, bevæge

idioms:

• motor home    autocamper
• motor neurone    bevægenerve, motorisk nerve
• motor racing    motor(vædde)løb
• motor scooter    scooter

Nederlands (Dutch)
motor, motorisch, met de auto vervoeren

Français (French)
n. - bagnole, (Élec, Mécan) moteur, (fig) moteur de, bagnole (arch)
adj. - (Aut) automobile, de l'automobile, (Méd) moteur
v. intr. - aller en auto (arch), rouler, tracer (fam), aller vite
v. tr. - rouler, conduire en auto (arch)

idioms:

• motor home    auto-caravane, camping-car
• motor neurone    (Méd) (maladie) latérale amyotrophique
• motor racing    course automobile
• motor scooter    scooter

Deutsch (German)
n. - Motor
adj. - Motor-, Kraftfahrzeug-, motorisch
v. - (mit dem Auto) fahren

idioms:

• motor home    Wohnmobil, Reisemobil
• motor neurone    motorischer Nerv
• motor racing    Autorennsport
• motor scooter    Motorroller

Ελληνική (Greek)
n. - κινητήρας (κν. μοτέρ), (αυτοκίνητο) όχημα
adj. - κινητήριος, (φυσιολ.) κινητικός
v. - διακινώ/-ούμαι ή ταξιδεύω με αυτοκίνητο

idioms:

• motor home    τροχόσπιτο
• motor neurone    κινητήριος νευρώνας
• motor racing    αυτοκινητοδρομία
• motor scooter    μηχανοκίνητο δίκυκλο, σκούτερ, βέσπα

Italiano (Italian)
motore, viaggiare in auto

idioms:

• motor home    roulotte
• motor neurone    motoneurone (anat.)
• motor racing    corsa di auto
• motor scooter    motorino

Português (Portuguese)
n. - motor (f), carro (m)
adj. - motorizado
v. - passear ou viajar de carro

idioms:

• motor home    trailer (m)
• motor neurone    nervo motor (m) (Anat.)
• motor racing    corrida de carros (f)
• motor scooter    motoneta (f)

Русский (Russian)
двигатель, автотранспорт, двигательный мускул, движущий, моторный, ехать на автомобиле

idioms:

• motor home    дом на колесах
• motor neurone    мотонейрон
• motor racing    автомобильные гонки
• motor scooter    скутер

Español (Spanish)
n. - motor, coche, automóvil, carro
adj. - motriz, de motor
v. intr. - ir o viajar en coche
v. tr. - impulsado por motor, llevar en automóvil o avión

idioms:

• motor home    caravana, casa rodante
• motor neurone    neurona motora
• motor racing    automovilismo deportivo, carrera de coches
• motor scooter    motoneta, escúter, motopatín

Svenska (Swedish)
n. - motor, bil, motorisk muskel, motorisk nerv
adj. - motorisk
v. - bila

中文（简体）(Chinese (Simplified))
马达, 汽车, 原动力, 发动机, 电动机, 马达的, 发动的, 汽车的, 驾驶汽车, 乘汽车, 推动, 以汽车载运

idioms:

• motor home    汽车房屋, 露营车, 旅宿车
• motor neurone    运动神经
• motor racing    赛车
• motor scooter    小型摩托车

中文（繁體）(Chinese (Traditional))
n. - 馬達, 汽車, 原動力, 發動機, 電動機
adj. - 馬達的, 發動的, 汽車的
v. intr. - 駕駛汽車, 乘汽車
v. tr. - 推動, 以汽車載運

idioms:

• motor home    汽車房屋, 露營車, 旅宿車
• motor neurone    運動神經
• motor racing    賽車
• motor scooter    速克達機車

한국어 (Korean)
n. - 발동기, 자동차, 원동력, 운동 신경
adj. - 원동력의, 자동차의, 운동 신경의
v. intr. - 자동차를 타다[가다]
v. tr. - 자동차로 운반하다

日本語 (Japanese)
n. - 原動機, 原動機付き乗物, 自動車, 原動力, 自動車株
v. - 自動車で運ぶ, 自動車に乗る
adj. - 動かす, 発動機の

idioms:

• motor home    モーターホーム
• motor neurone    刺激を伝える神経細胞
• motor racing    自動車レース
• motor scooter    スクーター

العربيه (Arabic)
‏(الاسم) محرك, مركبه (صفه) متعلق بالمركبات (فعل) يسوق المركبه‏

עברית (Hebrew)
n. - ‮מנוע, מכונית, קרונוע, מעונוע‬
adj. - ‮ממונע, מנועי, תנועתי, יוצר תנועה, מוטורי, של מכוניות, של תנועת שריר‬
v. intr. - ‮נסע במכונית‬
v. tr. - ‮הוביל במכונית‬

If you are unable to view some languages clearly, click here.