Download - 2017.01.18 magnetisme v76 400 b
![Page 1: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/1.jpg)
Rm
1/H - Henry (H -1)
Reluktans2017.01.23
MAGNETISME
![Page 2: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/2.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
Φ = Magnetisk fluks (phi) målt i Weber (Wb)B = Magnetisk flukstetthet målt i Tesla (T)H = Magnetisk feltstyrke målt i ampere per meter (A/m)L = Induktans (selvinduktans) i spole, målt i henry (H)Rm = Reluktans, magnetisk resistans målt i 1/Henry (1/H)Λ = Permeans (lamda) magnetisk ledningsevne målt i henry (H)
μ0 = Permeabilitetskonstant for vakuum i henry per meter (H/m)
μr = Relativ permeabilitet (ubenevnt, se verdier i tabell)
μ = μ0 · μr = Permeabilitet målt i henry per meter (H/m)
![Page 3: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/3.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
Rm = Reluktans, magnetisk resistans målt i 1/Henry (1/H)
![Page 4: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/4.jpg)
Side 68
![Page 5: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/5.jpg)
![Page 6: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/6.jpg)
Fm
Henry (H / m)
Magnetomotorisk
spenning
Fm = Φ · Rm
![Page 7: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/7.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
Fm = Magnetomotorisk
spenning
Henry (H / m)
![Page 8: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/8.jpg)
Side 68
Fm = Φ · Rm
![Page 9: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/9.jpg)
FNewton (N)
Magnetisk
trekkraft
![Page 10: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/10.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
F = Magnetisk trekkraft målt i newton (N)
F =
![Page 11: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/11.jpg)
![Page 12: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/12.jpg)
B = μ·H = μ
F =
F = Magnetisk trekkraft målt i newton (N)
![Page 13: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/13.jpg)
B = μ F =
F = Magnetisk trekkraft målt i newton (N)
F =
![Page 14: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/14.jpg)
![Page 15: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/15.jpg)
Strømkabel
![Page 16: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/16.jpg)
μ Henry (H / m)
Permeabilitet
![Page 17: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/17.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
Φ = Magnetisk fluks (phi) målt i Weber (Wb)B = Magnetisk flukstetthet målt i Tesla (T)H = Magnetisk feltstyrke målt i ampere per meter (A/m)L = Induktans (selvinduktans) i spole, målt i henry (H)Rm = Reluktans, magnetisk resistans målt i 1/Henry (1/H)Λ = Permeans (lamda) magnetisk ledningsevne målt i henry (H)
μ0 = Permeabilitetskonstant for vakuum i henry per meter (H/m)
μr = Relativ permeabilitet (ubenevnt, se verdier i tabell)
μ = μ0 · μr = Permeabilitet målt i henry per meter (H/m)
![Page 18: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/18.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
μ0 = Permeabilitetskonstant for vakuum i henry per meter (H/m)
μr = Relativ permeabilitet (ubenevnt, se verdier i tabell)
μ = μ0 · μr = Permeabilitet målt i henry per meter (H/m)
![Page 19: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/19.jpg)
μ = μ0 · μr = Permeabilitet målt i henry per meter (H/m)
![Page 20: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/20.jpg)
Øving !
![Page 21: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/21.jpg)
Kap 5 Oppgave 5
Side 82
Kapittel 5:Løs oppgave 5 a) b) c) og d)
![Page 22: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/22.jpg)
STØRRELSESSYMBOLER FOR MAGNETISME:.
H = Magnetisk feltstyrke målt i ampere per meter (A/m).
B = Magnetisk flukstetthet målt i Tesla (T).
Rm = Reluktans, magnetisk resistans målt i 1/Henry (1/H).
L = Induktans (selvinduktans) i spole, målt i henry (H)
Side 82
![Page 23: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/23.jpg)
Side 82
![Page 24: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/24.jpg)
Kap 5 Oppgave 5 a)
Side 82
![Page 25: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/25.jpg)
Kap 5 Oppgave 5 a)
μ0 = 1,257 μH/mI = 1 A l = 12cm = 0,12mN = 500 d = 1cm = 0,01m r = d/2 = 0,005m = 5·10-3 m
Side 82
![Page 26: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/26.jpg)
Side 82
![Page 27: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/27.jpg)
H = =
Side 82
![Page 28: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/28.jpg)
H = = =
Side 82
![Page 29: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/29.jpg)
H = = = 4167 A/m
Kap 5 Oppgave 5 a)
FASIT:
Side 82
![Page 30: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/30.jpg)
Kap 5 Oppgave 5 b)
Side 82
![Page 31: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/31.jpg)
Kap 5 Oppgave 5 b)
Side 82
![Page 32: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/32.jpg)
Kap 5 Oppgave 5 b)
B
Side 82
![Page 33: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/33.jpg)
B = μ·H = μ
Side 82
![Page 34: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/34.jpg)
Kap 5 Oppgave 5 b)
Permeabilitetskonstant i luft:μ0 = 1,257 μH/mFeltstyrken:H = 4167 A/m
Side 82
![Page 35: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/35.jpg)
Kap 5 Oppgave 5 b)
B = μ·H = = 1,257 μH/m · 4167 A/m =
FASIT:
Side 82
![Page 36: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/36.jpg)
Kap 5 Oppgave 5 b)
B = μ·H = = 1,257 μH/m · 4167 A/m == 5,24 mT FASIT:
Side 82
![Page 37: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/37.jpg)
Kap 5 Oppgave 5 c)
Side 82
![Page 38: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/38.jpg)
Kap 5 Oppgave 5 c)
Side 82
![Page 39: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/39.jpg)
![Page 40: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/40.jpg)
Side 82
Kap 5 Oppgave 5 c)
Rm = Reluktans, magnetisk resistans målt i 1/Henry (1/H)
Rm = =
= = 1,22nH
μ0 = 1,257 μH/mI = 1 A l = 12cm = 0,12mN = 500 d = 1cm = 0,01m r = d/2 = 0,005m = 5·10-3 m
FASIT:
![Page 41: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/41.jpg)
Kap 5 Oppgave 5 d)
Side 82
![Page 42: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/42.jpg)
L = Induktivitet eller induktans i [H = Henry]μ0 = absolutt permeabilitet (4·π·10−7 [H/m])μr = relativ permeabilitet til materialet i kjernen.
For vakuum er verdien lik 1, og den er ikke så mye forskjellig for de fleste andre materialer somikke er ferromagnetiske.
N = antall vindinger (uten benevning)A = Arealet til kjernen [m2]l = lengden til spolen i [m].
lANL 2
![Page 43: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/43.jpg)
Side 82
Kap 5 Oppgave 5 d)
lANL 2
= = = 205,6
FASIT:
![Page 44: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/44.jpg)
Øving ! Kap 5 Oppgave 6
![Page 45: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/45.jpg)
Kap 5 Oppgave 6
Side 82
Kapittel 5:Løs oppgave 6 a) b) c) d) og e)
FASIT:
![Page 46: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/46.jpg)
Side 82
Kap 5 Oppgave 6 a)
![Page 47: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/47.jpg)
μ = μ0 · μr = Permeabilitet målt i henry per meter (H/m)
Kap 5 Oppgave 6 a)
![Page 48: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/48.jpg)
μ = μ0 · μr = 1,257 μH/m · 2500 = 3,14 mH/m
Kap 5 Oppgave 6 a)
Lengde = 12cm = 0,12m
Areal = 1 cm2=0,1·10-3 m2
μr = 2500
μ0 = 1,257 μH/m FASIT:
![Page 49: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/49.jpg)
Side 82
Kap 5 Oppgave 6 b)
![Page 50: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/50.jpg)
Kap 5 Oppgave 6 b)
Lengde = 12cm = 0,12m
Areal = 1 cm2=0,1·10-3 m2
μr = 2500
μ0 = 1,257 μH/m FASIT:
= 10 mH
![Page 51: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/51.jpg)
lANL 2
![Page 52: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/52.jpg)
Kap 5 Oppgave 6 b)
Lengde = 12cm = 0,12m
Areal = 1 cm2=0,1·10-3 m2
μr = 2500
μ0 = 1,257 μH/m FASIT:
lANL 2
= 10 mH
![Page 53: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/53.jpg)
lANL 2
Vi må snu om på formelen, slik at vi får antall viklinger N alene på venstre side av likningen !
Kap 5 Oppgave 6 b)
![Page 54: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/54.jpg)
𝑳=𝑵 2·𝝁 · 𝑨
𝒍
𝑳 · 𝒍=𝑵 2·𝝁 · 𝑨 · 𝒍𝒍
𝑳 · 𝒍=𝑵 2·𝝁 · 𝑨
Kap 5 Oppgave 6 b)
![Page 55: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/55.jpg)
𝑳 · 𝒍=𝑵 2·𝝁 · 𝑨
𝑳· 𝒍𝝁 · 𝑨=
𝑵 2·𝝁 ·𝑨𝝁 ·𝑨
𝑳· 𝒍𝝁 · 𝑨=
𝑵 2
Kap 5 Oppgave 6 b)
![Page 56: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/56.jpg)
𝑳· 𝒍𝝁 · 𝑨=
𝑵 2
𝑵 2= 𝑳 · 𝒍𝝁 · 𝑨
Kap 5 Oppgave 6 b)
𝑵=√ 𝑳 · 𝒍𝝁 · 𝑨
![Page 57: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/57.jpg)
Kap 5 Oppgave 6 b)
Lengde = 12cm = 0,12m
Areal = 1 cm2=0,1·10-3 m2
μr = 2500 μ = 3,14mH/m
μ0 = 1,257 μH/m FASIT:
= = 62
= 10 mH
NB: Feil i fasit !
![Page 58: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/58.jpg)
Side 82
![Page 59: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/59.jpg)
Kap 5 Oppgave 6 c)
![Page 60: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/60.jpg)
Kap 5 Oppgave 6 c)
R = = = 600 ΩFASIT:
![Page 61: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/61.jpg)
Side 82
![Page 62: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/62.jpg)
Kap 5 Oppgave 6 d)
H =
![Page 63: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/63.jpg)
Kap 5 Oppgave 6 d)
H =
H = = = 5,17 A/mFASIT:
![Page 64: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/64.jpg)
Side 82
![Page 65: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/65.jpg)
Kap 5 Oppgave 6 e)
![Page 66: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/66.jpg)
Kap 5 Oppgave 6 e)
B = μ·H = = 3,14 mH/m · 5,17 A/m =
= 16,6 mT FASIT:
NB: Feil i fasit !
![Page 67: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/67.jpg)
Høyrehånds-regelen !
![Page 68: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/68.jpg)
Her går strømmen fra oss, og magnetfeltet roterer med klokken.
Her kommer strømmen mot oss, og magnetfeltet roterer mot klokken.
Høyrehåndsregelen:
Holder man en leder, med tommelen pekende i strømretningen, så vil
lederens magnetfelt rotere i den retningen som fingrene peker.
![Page 69: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/69.jpg)
Side 63
Høyrehåndsregelen
![Page 70: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/70.jpg)
Side 63
Høyrehåndsregelen
![Page 71: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/71.jpg)
Venstrehånds-regelen !
Venstrehåndsregelen:
Fører man venstre hånd
inn i et magnetfelt, slik at
feltlinjene går inn i
håndflaten og ut gjennom
håndbaken, og fingrene
peker i strømretningen, så
vil tommelen peke i
kraftretningen.
![Page 72: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/72.jpg)
Venstrehåndsregelen:Fører man venstre hånd inn i et magnetfelt, slik at
feltlinjene går inn i håndflaten og ut gjennom
håndbaken, og fingrene peker i strømretningen, så
vil tommelen peke i kraftretningen.
![Page 73: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/73.jpg)
Magnetiske feltkrefter
![Page 74: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/74.jpg)
Induksjon er en måte å skaffe elektromotorisk spenning på.
Motorprinsippet innebærer at en strømførende leder som er plassert i et magnetfelt, beveger seg.
Elektrisk energi blir omdannet til mekanisk bevegelsesenergi.
![Page 75: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/75.jpg)
Generatorprinsippet innebærer at en omdanner mekanisk bevegelsesenergi til elektrisk energi.
![Page 76: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/76.jpg)
Leder er i ro F = B · I · l
![Page 77: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/77.jpg)
![Page 78: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/78.jpg)
F = B · I · l
Når det går strøm i lederen som vist her, vil det oppstå en kraft på lederen vinkelrett på magnetfeltet.
![Page 79: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/79.jpg)
F = B · I · l
Høyrehåndsregelen
![Page 80: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/80.jpg)
F = B · I · l
Høyrehåndsregelen
![Page 81: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/81.jpg)
F = B · I · l
![Page 82: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/82.jpg)
F kraften som magnetfeltet utøver på lederen (Newton) B flukstettheten (Tesla) I strømmen i lederen (Ampere) l lederlengden (meter) Kraft som virker på en strømførende leder i et magnetfelt er bestemt av feltlinjene mellom permanentmagnetene og feltlinjene rundt lederen. Av figur 5.2.2 ser vi at feltlinjene går samme veg på høyre side av lederen mens det på venstre side går hver sin veg. Dette medfører at feltet blir forsterket på høyre side, men det blir svekket på venstre side fordi feltlinjene der prøver å motvirke hverandre.
F = B · I · l
![Page 83: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/83.jpg)
Kraft mellom to parallelle ledere:
![Page 84: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/84.jpg)
Side 67
![Page 85: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/85.jpg)
Side 67
![Page 86: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/86.jpg)
Side 67
![Page 87: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/87.jpg)
Induksjon ved fluksendring:
![Page 88: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/88.jpg)
![Page 89: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/89.jpg)
Ut fra definisjonen over er alle størrelsene unntatt N i utrykket over del av permeansen til spolen.
Som en ser skal antallet vindinger kvadreres i formelen, dermed er det ikke mange vindinger som skal til før induktansen økes betraktelig.
![Page 90: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/90.jpg)
I litteraturen er det vanlig å analysere spoler spesielt og betrakte disse som et selvstendig kretselement, selv om alle ledere har induktans.
Årsaken er at i kretsanalyse vil spolene representere en mye større induktans enn lederne ellers i kretsen. Å ignorere ledernes induktans betyr derfor lite.
![Page 91: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/91.jpg)
![Page 92: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/92.jpg)
I en magnetisk krets kan en se på fluksen Φ som en strøm som ledes gjennom den, som drives av en potensialforskjell og som møter en motstand.
En magnetisk krets kan være transformatoren.
En transformator har en jernkjerne som gir meget høy permeans, noe som er ønskelig for å gi god magnetisk kobling mellom de to viklingene.
Dermed vil transformatoren gi en energiomsetning med små tap.
![Page 93: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/93.jpg)
I en slik krets vil permeansen bli større for et stort tverrsnitt av materialet (kjernens tverrsnitt i transformatoren i figuren), og motsatt høyere for større lengde.
Dette konseptet er analog med elektrisk ledningsevne og elektrisk konduktivitet i en elektriske krets.
![Page 94: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/94.jpg)
En transformator med jernkjerne og viklinger (spoler) på hver side omtalt som
primærvikling (primary winding på figuren, der spenningskilden er tilknyttet) og
sekundærvikling (secondary winding på figuren, der belastningen er tilknyttet).
![Page 95: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/95.jpg)
Hensikten med jernkjernen er å gi så høy permeans som mulig. Årsaken ligger i at såkalte ferromagnetiske materialer er gode ledere for magnetiske felter.
Denne transformatoren har ingen lekkfluks, det vil si at all fluks er i jernkjernen.
Dette er et av kjennetegnene på en ideell transformator.
![Page 96: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/96.jpg)
Leder beveger seg
Induksjon i rette ledere i jevn bevegelse i et magnetfelt.
E = B · l · v · N
![Page 97: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/97.jpg)
Induksjon i rette ledere i jevn bevegelse
E = B · l · v · N
![Page 98: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/98.jpg)
E= B · l · v · N
![Page 99: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/99.jpg)
![Page 100: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/100.jpg)
![Page 101: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/101.jpg)
Stjerneklart
![Page 102: 2017.01.18 magnetisme v76 400 b](https://reader034.vdocuments.us/reader034/viewer/2022042706/5885f32b1a28ab864f8b631d/html5/thumbnails/102.jpg)
THE END !Thank You !