1

Reference I will refer to is Textbook of Electrical Technology by Theraja, page 268 (iv) Magnetising Force on the Axis of a Short Solenoid

The derivation is already there. I just don't understand the visuals that well because they look so complicated. I don't get the use of the variables clearly such as the θ, dx, θ1, θ2, r, and l and even the points M, N and P. Recently I have already studied and understood (iii) Magnetising Force on the Axis of a Circular Coil. But what I don't get is why they have to use that on this part even though this is about a short solenoid. It's not even circular. I am already lost with the whole, use the circular coil thing. I understand the idea of using differentials to represent infinitesimal values but the situation this time feels so complicated.

I mean, the derivation is already there and pretty clear for someone else who probably understands the topic. I just want a more clear explanation, especially on the visuals and how it relates to the Circular Coil geometry.

AndroidV11
  • 449
  • 8
  • 18
  • Can you add the photos of the relevant figures? Possibly the links to the relevant pages in Google books. – AJN Aug 30 '20 at 03:39
  • I could not find it in Google books but I added the figure. – AndroidV11 Aug 30 '20 at 03:50
  • If they start with dx, I think they finally convert it to dtheta so that the integration becomes easier. – AJN Aug 30 '20 at 04:11
  • "It's not even circular" What do you mean ? Is the wire wound on a square or rectangular (or other) prism ? Isn't circular coil and short solenoid nearly the same ? – AJN Sep 02 '20 at 03:18
  • What I mean is it's not explicitly stated. Now if you were to tell me that short solenoid is assuming an original circular coil then that would explain many things but my question is what is the basis for that? Just curious. – AndroidV11 Sep 02 '20 at 04:30
  • I don't know if I am referring to the same text book as your are, but the author mentions that the solenoid can be regarded as circular one turn coils placed close together (total turns / total length circular coils per unit length). So the formula for the circular coil is used as the basis for deriving the magnetising force for the solenoid. The circular coil formula takes care of the integration around a single[sic] loop. What is remaining is to integrate the expression over all the loops, which is equivalent to integrating over the length of the solenoid. – AJN Sep 02 '20 at 04:55
  • I think your explanation delivers but I just don't understand it that well. Do you mean that the circular coil has like only one loop and a solenoid has multiple loops, which is why you said all? Sorry, I think you know what you are saying and I am just still comprehending. – AndroidV11 Sep 02 '20 at 05:28
  • Yes, that is what i meant by all loops. The solenoid is like having N numbers of single loop coils which are evenly spaced within a length of l. – AJN Sep 02 '20 at 05:52

0 Answers0