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Name: Jon
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Question:
When using a copper coil and magnets to generate an EMF is it the number of "wraps" in the coil or the amount of copper in the coil that is more important? Is a smaller gauge wire with more wraps better than a larger gauge wire with fewer wraps?



Replies:
Hi Jon

The number of turns (wraps) is directly proportional to the EMF that you can obtain for a given area within a magnetic field. Generator design becomes an engineering problem in which you try to balance size and performance. For further reference, check out Faraday's law. It states that the magnitude of EMF is equal to the number of turns times the time rate of change of the magnetic flux. Hope this helps.

Bob Froehlich


Jon,

There are three major factor to consider: number of loops, density of loops, radius of the loops. If the number of loops is large enough and the radius is small enough, then you have a solenoid. Density of loops becomes the major concern. If the coil is much wider than it is long, number of loops and average radius are the major concerns: N/r. As most electromagnets are in the form of a coil that is at least as long as it is wide, a solenoid is probably a good model.

The advantage of thin wire is that you get more loops per centimeter. The advantage of thick wire is that you can handle more current. The product of the two (current times loops per centimeter) is what determines the magnetic field inside the coil and near the openings. If you can limit the current, then the narrower gauge gives the same magnetic field with less current. This is safer. If the current cannot be limited, then use the wider gauge to prevent overheating of the coil. In either case, a longer wire wrapped in a coil of more loops per centimeter (i.e. more layers, smaller radius) should provide the stronger field.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College


Question as I understand it is the windings say the number have impact on its use or result.

A core/ transformer frequently called or say electromagnetis and similar. The larger the magnet is both dependent on the number of windings and the thickness.. Please start with a look at ohms law and follow by inductance and magnetism there. Remember the greater the windings we are increasing the amount of current handled and thickness i.e. tolerances the amount of voltage that is dealt with,...... all deal with the amount of power as an end result. Keep in mind also that materials can change parameters, I also for the more advanced to read about super conducting etc.

Prof. Przekop, Physicist



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