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Armature magnetomotive force (mmf) is caused by current flow in armature windings. The source of mmf is armature reaction that is why the term "armature" is used.
Answer
Magnetic circuits are often compared with electriccircuits. A magnetomotive force (equivalent to 'voltage') creates magnetic flux (equivalent to 'current'), which is opposed by reluctance (equivalent to 'resistance').
So a magnetomotive force is the source of magnetic flux, and is the product of the current passing through a winding and the number of turns of that winding. In SI, it is expressed as amperes (although it is generally 'spoken' as ampere-turns).
As the original answer explains, an armature magnetomotive force is simply that set up by the current passing through the machine's armature.
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Why is alternating voltage induced in the rotating armature of a generator?
The windings of the armature are constantly cutting magnetic lines of force of opposite polarities
What is the difference between emf and mmf?
emf is electromotive force mmf is magnetic motive force emf drives electon where as mmf drives magnetic field
What makes the armature in the electric motor rotate?
from Faraday's law of electromagnetic induction : when a current carrying conductor cuts the magnetic field an E.M.F (electro motive force) is produced and it sets up in such a direction so as to oppose the cause of it. the stator winding of a motor which produces the R.M.F (rotating magnetic field) serves as the magnetic field and the armature winding is the current carrying conductor which cuts the magnetic field , thus an EMF is induced in the armature which again produces a force to oppose the emf produced in the armature winding.
What is the purpose of the fields of a dc shunt motor?
DC Shunt motor: dc shunt motor is a motor with dc supply given to the inductor connected in parallel with the armature of a motor. The inductor connected in parallel with the armature of a motor called field winding of a motor.In dc shunt motor: When current flows through a conductor ( here it is armature in case of dc shunt motor ), magnetic field is produced which is circular and when this conductor is placed perpendicular in the magnetic field ( which is produced by the current or say dc supply that given to the inductor or say field winding of the dc shunt motor ), the main magnetic lines get bent due to the interaction of the two fields. These lines of force experience tension and try to become straight. So, a force is produced on the conductor ( armature ), due to which the conductor ( armature ) will rotates. The direction of force can be found by Fleming's right hand rule.Main Answer: Thus, it should be understood that field winding in dc shunt motor stands to get interaction of the two field in such a way that force is produced on the armature so that the armature get to rotate.Some Facts: Actually the current in armature is due to the mutual induction by field winding to the armature. That means only field winding get dc supply through which current and so magnetic field is produced in armature that try to oppose due which it is produced, that means it oppose the main magnetic field of field winding.
Why direction of rotation is not reversed when both field and armature terminals are reversed?
The direction of the force that drives the machine is determined by the relative directions of the field and the armature current. By reversing the direction of both field and the armature current, the direction of the resulting force stays the same; you have to reverse the direction of one or the other; not both! Prove it for yourself, by applying Fleming's Left-Hand Rule (for conventional current flow); reverse the direction of both your first finger (field) and your second finger (armature current), and you thumb (direction of motion) will end up pointing in the same direction!
What is inverse of inductance?
reluctance, it is the resistance of a magnetic circuit to the establishment of a magnetic flux by a magnetomotive force.
What is motivational force?
mmf is which sets up or tends to set up the magnetic flux in magnetic circuitNote. The term is magnetomotive force, notmagnetic motive force. For a coil, the magnetomotive force is the product of the current flowing in that coil and the number of turns, and is measured in amperes (A), although it is often spoken as 'ampere turns', to avoid any confusion with current.
Definition of Quadrature axis?
Quadrature axis of a magnetomotive force is defined as that component of MMF that is directed along an axis in quadrature with the axis of the field poles. Quadrature axis of a magnetomotive force is defined as that component of MMF that is directed along an axis in quadrature with the axis of the field poles.
What is magnetic motive force?
mmf is which sets up or tends to set up the magnetic flux in magnetic circuitNote. The term is magnetomotive force, notmagnetic motive force. For a coil, the magnetomotive force is the product of the current flowing in that coil and the number of turns, and is measured in amperes (A), although it is often spoken as 'ampere turns', to avoid any confusion with current.
What is magnetomotive force per unit length?
Magnetomotive force per unit length is the definition of magnetic field strength (symbol: H), formerly known as 'magnetising force'.Magnetomotive force is the product the the current flowing through a coil and the number of turns that make up that coil, and its SI unit of measurement is the ampere (although this is often spoken as 'ampere turn').So, the SI unit of measurement of magnetic field strength is the ampere per metre, although, again, it is often spoken as 'ampere turn per metre'.
Why is alternating voltage induced in the rotating armature of a generator?
The windings of the armature are constantly cutting magnetic lines of force of opposite polarities
What is ampere turn formula?
Magnetomotive force establishes magnetic flux in a magnetic circuit, which is opposed by the reluctance of that circuit. It's easy to relate these magnetic quantities to the equivalent quantities in an electric circuit:magnetomotive force is equivalent to electromotive forceflux is equivalent to currentreluctance is equivalent to resistanceA magnetomotive force (mmf) is created whenever an electric current passes through a coil. It's magnitude is determined by the product of the current (I) flowing through the coil and the number of turns (N): mmf = I NThe unit of measurement of magnetomotive force is the ampere. Although, to prevent it from being confused with the unit of measurement for current, it is usually spoken as "ampere turn".
How is torque produced in a dc motor?
torque = force x Radius of the armature
What is an ampere-turn?
An ampere-turn is the unit of magnetomotive force, the work required to carry a magnetic monopole of unit strength once around a magnetic circuit.
What is the difference between emf and mmf?
emf is electromotive force mmf is magnetic motive force emf drives electon where as mmf drives magnetic field
What is the ampere a unit of?
Ampere is the basic unit of electrical current.AnswerThere are, in fact, two answers. The ampere is the SI Base Unit for electric current, but it is also the SI Derived Unit for magnetomotive force.
What makes the armature in the electric motor rotate?
from Faraday's law of electromagnetic induction : when a current carrying conductor cuts the magnetic field an E.M.F (electro motive force) is produced and it sets up in such a direction so as to oppose the cause of it. the stator winding of a motor which produces the R.M.F (rotating magnetic field) serves as the magnetic field and the armature winding is the current carrying conductor which cuts the magnetic field , thus an EMF is induced in the armature which again produces a force to oppose the emf produced in the armature winding.
