Electrical Engineering ⇒ Topic : Magnetising Force (H) Produced by Electric Current

Magnetising Force (H) Produced by Electric Current

The magnetic flux (Φ) can be produced by (i) current-carrying conductor or coil or (i i) a permanent magnet. We generally use current-carrying conductor or coil to produce magnetic flux. Experiments show that magnetic flux (Φ) produced by a current-carrying coil is directly proportional to the product of number of turns (N) of the coil and electric current (1) which the coil carries. The quantity NI is called magnetomotive force (m.m.f) and is measured in ampere-turns (AT) or *amperes (A)

                                                                  m.m.f. = NI Ampere-turns (AT)

Just as e.m.f. (electromotive force) is required to produce electric current in an electric circuit, similarly, m.m.f. is required to produce magnetic flux in a **magnetic circuit. The greater the m.m.f., the greater is the magnetic flux produced in the magnetic circuit and vice-versa.

The magnetising force (H) produced by an electric current is defined as the m.m.f set up per unit length of the magnetic circuit i.e.

Different current-carrying conductor arrangements produce different magnetising force. Magnetising force (H) is known by different names such as magnetic field strength, magnetic intensity and magnetic potential gradient