In physics, the Magneto Motive Force (MMF) is a quantity appearing in the equation for the magnetic flux in a magnetic circuit, sometimes known as Hopkinson's law:
where Φ is the magnetic flux and R is the magnetic reluctance of the circuit. It can be seen that the magnetomotive force plays a role in this equation analogous to the voltage V in Ohm's law: V = IR.
Magnetomotive force is the thought to be the same as electromotive force, emf (= difference in electric potential, or voltage, between the terminals of a source of electricity, e.g., a battery from which no current is being drawn) since it is the cause of magnetic flux in a magnetic circuit; i.e.,
- ℱ = NI
- where N is the number of turns in the coil and
- I is the electric current through the electrical circuit
- where N is the number of turns in the coil and
- ℱ = ΦR
- where Φ is the magnetic flux and
- R is the magnetic reluctance
- where Φ is the magnetic flux and
- ℱ = HL
References
- The Penguin Dictionary of Physics, 1977, ISBN 0-14-051071-0
- A textbook of Electrical Technology, 2008, ISBN 81-219-2440-5