Hi folks!(adsbygoogle = window.adsbygoogle || []).push({});

Long time listener-first time caller.

I am building a coil winder for building my own transformers-fun fun!

Anyway, I came across an interesting aspect associated with winding which, if not for anything else, provides an interesting math physycs problem.

I am trying to understand what happens with the magnet wire as it is spooled onto, lets say for simplicity, a square bobbin. The corners of the bobbin will lift the wire up and drag it forward, for a rotional distance of π/2 Radians - 90 degrees. After this, the cycle begins all over again, for another 90 degrees, until after four cycles, the bobbin has completed one turn. So we only need to look at a 90 degree segment, since this pattern repeats itself.

I brute forced this on a piece of polar graph paper to try and jump start my understanding of this winding process. I assumed that the wire comes from a point in space an infinite distance away so I could ignore the effects of the vertical transition as the bobbin rotates.

So, I am looking for the relationship between the angular velocity of the bobbin and the linear speed of the wire as it is spooled on the bobbin.

I am using a constant rotational velocity of the bobbin, which has a distance of 1 from it's center to it's outside edge, 90 degrees up from the center.

I need help deriving the equation for the linear wire speed.

Location would be an extra bonus!

Here is what I came up with so far, I started the math table with the corner at 45 degrees, rotated it in 5 degree increments, and took the difference in distance between the two, to get the horizontal distance traveled by the wire.

cos b - cos a = distance traveled

Thanks!

cj

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Coil Winding Mechanics

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**