Need help understanding the changing time portion of Faraday's law

Click For Summary
SUMMARY

The discussion focuses on calculating the changing time component of Faraday's Law of Electromagnetic Induction. The user presents a formula for induced voltage using parameters such as N=100, B=0.4 Tesla, and A=0.0025 m², ultimately deriving a voltage of 6.28 sin(ωt) volts. However, when adjusting parameters to N=32, B=0.5000 T, and A=0.00118 m², the user encounters discrepancies in the calculated voltage, leading to confusion regarding the time component in the equation. The user seeks clarification on the correct application of Faraday's Law and the proper interpretation of the time variable in their calculations.

PREREQUISITES
  • Understanding of Faraday's Law of Electromagnetic Induction
  • Familiarity with rotational motion concepts (RPM, RPS, angular velocity)
  • Basic knowledge of trigonometric functions (sine function)
  • Ability to manipulate and interpret mathematical equations
NEXT STEPS
  • Review the derivation of Faraday's Law and its application in electromagnetic induction
  • Study the relationship between angular velocity and induced voltage in rotating systems
  • Learn about the significance of the time component in electromagnetic calculations
  • Explore the use of LaTeX for formatting mathematical equations in discussions
USEFUL FOR

Physics students, electrical engineers, and anyone involved in electromagnetic theory or applications seeking to deepen their understanding of Faraday's Law and its practical calculations.

jearls74
Messages
53
Reaction score
1
I need infomation on how to calculate the changing time part of Faradays law. The answer i keep coming up with seems very low. I learned on this forum a few years ago, and i believe i have been doing it inproperly. Here is the formula i learned:

Use
N=100
B=0.4 Tesla (static field)
A = 5 cm by 5 cm (=0.05m x 0.05m = 0.0025 m2) rotating coil
RPM = 600; rps = 10 Hz; ω = 62.8 radians per second.

So V(t) = -N·d(B·A)/dt = -N·B·dA/dt = N·B·ω·A·sin(ωt)

=(100)(0.4)(62.8)(0.0025)sin(ωt) = 6.28 sin(ωt) volts

Does this top equation produce the correct answer for induced voltage.My parameters are as follows: - N=32
B=.5000 T
A=.00118 m2

This is how i have been calculating voltage:(1000 RPM) X (16 MAGNETS)= 16000 / 120 = 133.33Hz x (6.28) =
837.3124 w x.00118 m2 = .988028632 x .5000 T = .494014316 Volts x 32 conductors = 15.80 volts

I get a completely different number using Faradays Law equation:




( .5000 T x .00118 m2 ) = .00059 / .00119429 t = .49401736 volts x 32 conductors = 15.80 V V
d ( B X A )
-N ----------------- I got the time component
d t by dividing 1s by 837.3124 rad/s = .00119429 t

if i just use the 837.3124 radians as the time portion of the equation.

I end up with (.5000 T x .00118 m2) = .00059 / 837.3124 =7.04635450281 e-7

This last answer with the radians as the time component seems wrong.



farlaw-gif.24622.gif


Have i done this correct? any help is greatly appreciated.
 
Last edited:
I'm having trouble following your math. Use the little ∑ button or possibly the latex markup language?
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
11K
  • · Replies 6 ·
Replies
6
Views
3K