I am modeling the output voltage of an AC generator and I am using/I chose the following specifics:

  • Number coil turns = 300. This is 1.02 mm gauge copper wire, so knowing the density of copper, I calculated the weight of the coil being 4.39 kg.
  • Magnetic strength field = 1.24 T. Here are the specs for the magnet
  • Area of 0.1 m\$^2\$
  • The rpm will be 45

I want to know if the following variables I chose make sense.

Furthermore, I plugged these numbers into the output voltage equation

$$ε = NBAωsin(ωt)$$

to get a voltage value of 525.9. Is this number reasonable??

  • \$\begingroup\$ this site uses slash$ for mathjax \$\endgroup\$ – Neil_UK Mar 29 '16 at 5:39
  • \$\begingroup\$ \$ N B A \omega sin(\omega t) = 300 \cdot 1.24 \cdot 1 (2 \pi \frac {45}{60}) sin(\omega t)= 1753 sin(\omega t)\$ so that part is alright. (Remember that's about 1200 V rms.) I'm having difficulty imagining the physical layout of the magnet and \$ 1~m^2 \$ coil and how you maintain 1.24 T throughout. Can you expand your question to include a sketch of the physical construction? \$\endgroup\$ – Transistor Mar 29 '16 at 9:57
  • \$\begingroup\$ yes sorry i had a typo, it should read 0.1 for area and maximum voltage of 525.9 \$\endgroup\$ – user510 Mar 29 '16 at 14:04
  • \$\begingroup\$ And some clues regarding the layout? \$\endgroup\$ – Transistor Mar 29 '16 at 14:22
  • \$\begingroup\$ yes I don't know how the layout will look like (I am not very good at this). I had to model this for a project and because I do not know how this will look like, I was not sure if the numbers made sense. That is why I asked the question. \$\endgroup\$ – user510 Mar 29 '16 at 14:49

I think the calculation, area is took as 1 instead of 0.1. The voltage value in that case is 52.59 V. This is the Maximum Amplitude of voltage. For getting Vrms (Root Mean Square), divide it by sqrt(2).

  • \$\begingroup\$ Welcome to EE.SE. Incorrect. He already fixed the area error an hour ago. Edit your answer and show some calculations. This site uses MathJAX for formulas. See here for quick guide. \$\endgroup\$ – Transistor Mar 29 '16 at 15:36

Following thw Faraday's law, generalized for a solenoid with N turns, under magnetic field B, area A considered de ACTIVE area, ie, the intersection between the magnet area and the group of conductor where the magnetic flux lines cross over (that means, to simplify, that you need to consider the length of the vertical wires from one coil side - the other coil side will be another emf (ε). So, wsin(wt)? Well, it's the angular velocity. To simplify, Your rpm = 45. So, the angular velocity will be, if using a wheel with 12 inches, more or less you get 0,61 meters/second (the Faraday's formula ask to use metric dimensions). So, the imput data: ε = 300 * 1,24 * 0,02 (meters 2 cm - considered the mag dimension because i have no data from the coil) * 0,61 => ε = 4,53 volts.


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