Magnetomotive Force

Magnetomotive Force (mmf) :

Magnetomotive Force is the product of current and number of turns. More current and more turns leads to greater magnetizing effect. Unit of mmf is ampere turns.

mmf = NI ampere turns.

The amount of flux density set up in the core depend upon five factors,

• Current
• Number of turns
• Material of magnetic core
• Length of the core
• Cross sectional area of the core

Magnetic field strength / Magnetic field intensity / Magnetising force ( H) :

It is the magnetomotive force (mmf) per unit length.

H = MMF / Length = NI / L = Ampere turns / meter