Download - 3425
![Page 1: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/1.jpg)
ECE 441 1
Interaction of Magnetic Fields(Motor Action)
• Look at adjacent current-carrying conductors– Currents in opposite directions– Flux “bunching” between the conductors– Force of repulsion acts to separate the conductors
![Page 2: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/2.jpg)
ECE 441 2
Interaction of Magnetic Fields(Motor Action)
– Currents in the same direction– Flux in space between conductors in “opposite”
directions– Force of attraction acts to pull the conductors together
![Page 3: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/3.jpg)
ECE 441 3
Elementary Two-Pole Motor
• Rotor core with 2 insulated conductors in “slots”• A stationary magnet – the “stator”
![Page 4: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/4.jpg)
ECE 441 4
Current-Carrying Conductor in a Magnetic Field
![Page 5: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/5.jpg)
ECE 441 5
Current-Carrying Conductor in a Magnetic Field
• Current-carrying conductor perpendicular to the B-field
![Page 6: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/6.jpg)
ECE 441 6
Magnitude of the force on the conductor in a Magnetic Field
• Magnitude of the mechanical force on the conductor is
Where F = mechanical force (N)
B = flux density in the stator field (T)
= the effective length of the rotor conductor
I = current in the rotor conductor (A)
effectiveF Bl I
effectivel
![Page 7: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/7.jpg)
ECE 441 7
Conductor “skewed” to the B-fieldby angle
= effective length of the rotor conductor (m)effectivel
(sin )effectivel l
![Page 8: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/8.jpg)
ECE 441 8
Single-Loop Rotor CoilCarrying a Current
Situated in a Two-Pole Field
![Page 9: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/9.jpg)
ECE 441 9
Torque produced by the 2-conductor couple
2D
T Fd 2D effective
T Bl Id
![Page 10: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/10.jpg)
ECE 441 10
Elementary Two-Pole Generator
![Page 11: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/11.jpg)
ECE 441 11
Voltage induced in the coil, e
• Flux through the coil window is sinusoidal
• Φ = Φmaxsin(ωt)
• Voltage induced in coil,e• e = N(dΦ/dt)
• e = NωΦmaxcos(ωt)
• Emax = ωNΦmax
• Emax = 2πfNΦmax
• Erms = 4.44fNΦmax
![Page 12: 3425](https://reader036.vdocuments.us/reader036/viewer/2022062319/5589f8f2d8b42a1d4c8b471b/html5/thumbnails/12.jpg)
ECE 441 12
Directions of induced voltage and current
• Develop CCW counter-torque
• “Bunching” must occur at the top of coil side B and the bottom of coil side A
• Coil current is CCW as viewed from south pole