Engr. John Kenneth T. Sinson Instructor
MECHANICAL ENERGY ELECTRICAL ENERGY Generator Motor Coupling Field ELECTRO-MECHANICAL CONVERSION
Coupling Field ◦ ELECTRIC FIELD ◦ MAGNETIC FIELD
Magnetic Field ◦ Properties of Magnetic Line of Force It forms a closed loop, and doesn’t cross the path of other lines of force. Conventional direction is from North to South It is an elastic force. It travels the path of least reluctance.
1) Current produces magnetic field around a conductor (Hans Oersted, 1820) Right Hand Curl Rule
Ampere Circuital Law (Andre Ampere, 1823) ? ∙ ?𝑳 = ? Where: H-magnetic field intensity (A/m) dL-differential length of conductor I-magnitude of current
2) Steady magnetic field can’t produce current on a steady conductor . (Michael Faraday,1831) 3) Steady magnetic field can produce current on a moving conductor AND Changing Magnetic Field can produce a current on a steady conductor . (Michael Faraday,1831)
Michael Faraday’s Experiments
Faraday’s Law of Induction ◦ States that the induced EMF is equal to the rate of change of flux linkages ? = −𝑵 ?∅ ?? Lenz’s Law
4) Magnetic Field and Current-carrying Conductors 𝐿?????𝑧 ′ ? ????? ???𝑎?𝑖?? ? = ?? + ?(𝑩 ? 𝒗) *Assuming uniform distribution of magnetic line of force, and neglecting force due to electric field, ? = 𝐵𝐼𝐿 (𝑁?????) *F-force experienced by the conductor *I – magnitude of current *B-magnetic field density (Tesla) *L-length of conductor
In one revolution of the armature, the flux cut by one conductor is given as: Time for one revolution ?∅ = ∅ ∗ 𝑷 ????𝐫 ?? = 𝟔? 𝑵 ???????
By virtue of Faraday’s Equation: The number of conductors connected in series in each parallel path is equal to Z/a ? = ?∅ ??
- Spring '20
- Magnetic Field