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
? =
?∅
??

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- Spring '20
- Magnetic Field