Armature ( electrical engineering ) - wikipedia Armature ( electrical engineering ) A DC armature In electrical engineering, an armature is the power - producing component of an electric machine. The armature can be on either the rotor ( rotating part ) or the stator ( stationary part ) of the electric machine. The armature interacts with the magnetic field ( magnetic flux ) in the air - gap ; the field component can comprise either permanent magnets, or electromagnets formed by a conducting coil, such as another armature ( i.e., doubly - fed electric machine ). The armature, in contrast, must carry current, so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion, torque ( rotating machine ), or force ( linear machine ). The armature 's role is twofold. The first is to carry current crossing the field, thus creating shaft torque in a rotating machine or force in a linear machine. The second role is to generate an electromotive force ( EMF ). In the armature, an electromotive force is created by the relative motion of the armature and the field. When the machine is used as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical power in the form of torque, and transfers it via the shaft. When the machine is used as a generator, the armature EMF drives the armature current, and the shaft 's movement is converted to electrical power. In an induction generator, these distinctions are blurred, since the generated power is drawn from the stator, which would normally be considered the field. A growler is used to check the armature for shorts, opens and grounds. Contents 1 Terminology 2 Armature reaction in a DC machine 3 Winding materials 4 See also 5 References 6 External links Terminology The word armature was first used in its electrical sense, i.e. keeper of a magnet, in mid 19th century. The parts of an alternator or related equipment can be expressed in either mechanical terms or electrical terms. Although distinctly separate these two sets of terminology are frequently used interchangeably or in combinations that include one mechanical term and one electrical term. This may cause confusion when working with compound machines like brushless alternators, or in conversation among people who are accustomed to work with differently configured machinery. In most generators, the field magnet is rotating, and is part of the rotor, while the armature is stationary, and is part of the stator. Both motors and generators can be built either with a stationary armature and a rotating field or a rotating armature and a stationary field. The pole piece of a permanent magnet or electromagnet and the moving, iron part of a solenoid, especially if the latter acts as a switch or relay, may also be referred to as armatures. Mechanical Rotor : The rotating part of an alternator, generator, dynamo or motor. Stator : The stationary part of an alternator, generator, dynamo or motor Electrical Armature : The power - producing component of an alternator, generator, dynamo or motor. The armature can be on either the rotor or the stator. Field : The magnetic field component of an alternator, generator, dynamo or motor. The field can be on either the rotor or the stator and can be either an electromagnet or a permanent magnet. Armature reaction in a DC machine In a DC machine, the main field is produced by field coils. In both the generating and motoring modes, the armature carries current and a magnetic field is established, which is called the armature flux. The effect of armature flux on the main field is called the armature reaction. The armature reaction : demagnetizes the main field, and cross magnetizes the main field. The demagnetizing effect can be overcome by adding extra ampere - turns on the main field winding. The cross magnetizing effect can be reduced by having common poles. Armature reaction is essential in amplidyne rotating amplifiers. Armature reaction drop is the effect of a magnetic field on the distribution of the flux under main poles of a generator. Since an armature is wound with coils of wire, a magnetic field is set up in the armature whenever a current flows in the coils. This field is at right angles to the generator field, and is called cross magnetization of the armature. The effect of the armature field is to distort the generator field and shift the neutral plane. The neutral plane is the position where the armature windings are moving parallel to the magnetic flux lines, that is why an axis lying in this plane is called as magnetic neutral axis ( MNA ). This effect is known as armature reaction and is proportional to the current flowing in the armature coils. The brushes of a generator must be set in the neutral plane ; that is, they must contact segments of the commutator that are connected to armature coils having no induced emf. If the brushes were contacting commutator segments outside the neutral plane, they would short - circuit `` live '' coils and cause arcing and loss of power. Without armature reaction, the magnetic neutral axis ( MNA ) would coincide with geometrical neutral axis ( GNA ). Armature reaction causes the neutral plane to shift in the direction of rotation, and if the brushes are in the neutral plane at no load, that is, when no armature current is flowing, they will not be in the neutral plane when armature current is flowing. For this reason it is desirable to incorporate a corrective system into the generator design. These are two principal methods by which the effect of armature reaction is overcome. The first method is to shift the position of the brushes so that they are in the neutral plane when the generator is producing its normal load current. in the other method, special field poles, called interpoles, are installed in the generator to counteract the effect of armature reaction. The brush - setting method is satisfactory in installations in which the generator operates under a fairly constant load. If the load varies to a marked degree, the neutral plane will shift proportionately, and the brushes will not be the correct position at all times. The brush - setting method is the most common means of correcting for armature reaction in small generators ( those producing approximately 1000 W or less ). Larger generators require the use of interpoles. Winding materials The electrical energy efficiency of a motor can be improved by reducing the electrical losses in the coil ( e.g., by using materials with higher electrical conductivities ). Armature wiring is made from copper or aluminum. Copper armature wiring enhances electrical efficiencies due to its higher electrical conductivity. Aluminum armature wiring is lighter and less expensive than copper. See also Balancing machine Commutator References Jump up ^ `` armature ''. definition of armature in English from the Oxford dictionary. Retrieved July 17, 2015. Jump up ^ `` Basic AC electrical generators '' ( PDF ). American Society of Power Engineers. Jump up ^ A. Van Valkenburgh ( 1993 ). Basic Electricity. Thomson Delmar Learning. ISBN 0 - 7906 - 1041 - 8. Jump up ^ Armature reaction in DC machines, electricaleasy.com External links Example Diagram of an Armature Coil and data used to specify armature coil parameters How to Check a Motor Armature for Damaged Windings NDL : 00561363 Electric motors AC - Alternating current DC - Direct current PM - Permanent magnet SC - Self - commutated Fundamental types AC motor DC motor DC motors Homopolar Electrically - excited field or PM field brushed DC Unipolar AC SC mechanical commutator Repulsion Universal AC SC electronic commutator Brushless DC ( BLDC ) Switched reluctance ( SRM ) AC asynchronous ( induction ( IM ) ) Shaded - pole ( single - phase ) Dahlander pole changing motor Squirrel - cage rotor ( SCIM ) Wound - rotor ( WRIM ) Linear induction AC synchronous ( SM ) Hysteresis Interior / Surface PM ( IPMSM / SPMSM ) Reluctance ( SyRM ) Wound - rotor ( WRSM ) Special magnetic machines Doubly - fed Linear Servomotor Stepper Traction Non-magnetic Electrostatic Piezoelectric Ultrasonic Enclosure Type Hermetic TEFC Components and accessories Armature Braking chopper Brush Commutator DC injection braking Field coil Rotor Slip ring Stator Winding Motor controllers AC / AC converter Amplidyne Adjustable - speed drive ( ASD ) Cycloconverter Direct torque control ( DTC ) Metadyne Motor controller Motor soft starter Motor starter ( engine ) Power inverter Thyristor drive Variable - frequency drive ( VFD ) Vector control Voltage controller Ward Leonard control History, education, recreational use Timeline of the electric motor Ball bearing motor Barlow 's wheel Lynch motor Mendocino motor Mouse mill motor Experimental, futuristic Coilgun Railgun Superconducting machine Related topics Blocked - rotor test Circle diagram Closed - loop control Electromagnetism Open - circuit test Open - loop controller Power - to - weight ratio Torque and speed of a DC motor Two - phase system People Arago Baily Barlow Botto Cook Davenport Davidson Dolivo - Dobrovolsky Faraday Ferraris Froment Gramme Henry Jacobi Jedlik Lenz Maxwell Ørsted Park Pixii Saxton Siemens Sprague Steinmetz Stimpson Sturgeon Tesla See also Alternator Electric generator Inchworm motor SI electromagnetism units C - Capacitance ( F ) Q - Charge ( C ) G, B, Y - Conductance, susceptance, admittance ( S ) κ, γ, σ - Conductivity ( S / m ) I - Current ( A ) D - Electric displacement field ( C / m ) E - Electric field ( V / m ) Φ - Electric flux ( V m ) χ - Electric susceptibility U, ΔV, Δφ ; E - Emf ( V ) L, M - Inductance ( H ) H - Magnetic field ( A / m ) strength Φ - Magnetic flux ( Wb ) B - Magnetic flux density ( T ) χ - Magnetic susceptibility μ - Permeability ( H / m ) ε - Permittivity ( F / m ) P - Power ( W ) R, X, Z - Resistance, reactance, impedance ( Ω ) ρ - Resistivity ( Ω m ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Armature_(electrical_engineering)&oldid=803723119 '' Categories : Electromagnetic components Electric motors Talk Contents About Wikipedia Čeština Deutsch Eesti Español فارسی Français Հայերեն हिन्दी Hrvatski Kreyòl ayisyen 日本 語 Polski Русский کوردی Suomi Українська Edit links This page was last edited on 4 October 2017, at 06 : 10. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: rotating part of dc motor is known as
Answer: armature