A
conductor of length 200mm is placed at right angles to a magnetic field of
density 0.2T. If a current of 10A is maintained in the conductor, calculate the
force which acts on the conductor.
conductor of length 200mm is placed at right angles to a magnetic field of
density 0.2T. If a current of 10A is maintained in the conductor, calculate the
force which acts on the conductor.
Solution
Length
(L) = 200mm = 200 X 10⁻³ m
(L) = 200mm = 200 X 10⁻³ m
Magnetic
flux density (B) = 0.2T
flux density (B) = 0.2T
Current
(I) = 10A
(I) = 10A
Force
= BIL
= BIL
= 0.2 X 10 X 200 X 10⁻³
= 0.4 N
Example
2
2
An
air-cored coil wound with 500 turns, has a length of 250mm and a cross
sectional area of 400mm2. Calculate the magnetomotive force, the
magnetising force (H) and the total flux produced when a current of 5A is
maintained in the coil.
air-cored coil wound with 500 turns, has a length of 250mm and a cross
sectional area of 400mm2. Calculate the magnetomotive force, the
magnetising force (H) and the total flux produced when a current of 5A is
maintained in the coil.
Solution
Length
(L) = 250mm = 250 X 10⁻³
(L) = 250mm = 250 X 10⁻³
Number
of turns (N) = 500 turns
of turns (N) = 500 turns
Cross
sectional area (A) = 400mm2 = 400 X 10⁻⁶ m2
sectional area (A) = 400mm2 = 400 X 10⁻⁶ m2
Current
(I) = 5A
(I) = 5A
Magnetomotive
Force (Fm) = NI
Force (Fm) = NI
= 500 X5
= 2,500 A-turns
Total
flux (Φ) = BA
flux (Φ) = BA
Where
B = µoH
B = µoH
Φ = µoHA
= 0.4 X 10⁻⁶ X 10⁴ X 400 x 10⁻⁶ wb
= 5.03 X 10⁻⁶ wb
= 5.03 µwb
Example
3
3
A
coil of 200 turns is wound on an iron core of length 250mm and a cross
sectional area of 400mm2. If the iron has a relative permeability of
800, estimate the total flux produced when a current of 1.5A is maintained in
the coil.
coil of 200 turns is wound on an iron core of length 250mm and a cross
sectional area of 400mm2. If the iron has a relative permeability of
800, estimate the total flux produced when a current of 1.5A is maintained in
the coil.
Solution
Number
of turns (N) = 200 turns
of turns (N) = 200 turns
Length
(L) = 250mm =250 X 10⁻³ m
(L) = 250mm =250 X 10⁻³ m
Cross
sectional area (A) = 400mm2 = 400 x 10⁻⁶m2
sectional area (A) = 400mm2 = 400 x 10⁻⁶m2
Relative
Permeability (µr) = 800
Permeability (µr) = 800
Current
(I) = 1.5 A
(I) = 1.5 A
