Winding Definition and 105 Threads

An electromagnetic coil is an electrical conductor such as a wire in the shape of a coil, spiral or helix. Electromagnetic coils are used in electrical engineering, in applications where electric currents interact with magnetic fields, in devices such as electric motors, generators, inductors, electromagnets, transformers, and sensor coils. Either an electric current is passed through the wire of the coil to generate a magnetic field, or conversely, an external time-varying magnetic field through the interior of the coil generates an EMF (voltage) in the conductor.
A current through any conductor creates a circular magnetic field around the conductor due to Ampere's law. The advantage of using the coil shape is that it increases the strength of the magnetic field produced by a given current. The magnetic fields generated by the separate turns of wire all pass through the center of the coil and add (superpose) to produce a strong field there. The more turns of wire, the stronger the field produced. Conversely, a changing external magnetic flux induces a voltage in a conductor such as a wire, due to Faraday's law of induction. The induced voltage can be increased by winding the wire into a coil because the field lines intersect the circuit multiple times.The direction of the magnetic field produced by a coil can be determined by the right hand grip rule. If the fingers of the right hand are wrapped around the magnetic core of a coil in the direction of conventional current through the wire, the thumb will point in the direction the magnetic field lines pass through the coil. The end of a magnetic core from which the field lines emerge is defined to be the North pole.
There are many different types of coils used in electric and electronic equipment.

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  1. S

    Distance traveled winding around sphere

    Homework Statement I have a sphere that I want to travel from the north pole to the south pole. The route I take is winding around the sphere (instead of the obvious shortest path). My path is dictated by: ##\phi(t)=wt## ##z(t)=R-v_z t## in the negative z direction per N to S The form...
  2. P

    Transformer winding resistances R1, R2 and Re1 and inductances

    Hi, If there are no resistance and impedance parameters given for a single phase transformer, is it possible to work out the values of primary and secondary winding inductance and resistance (r1,r2,re1, x1,x2,xe1 etc) without the use of a short circuit test. The transformer can be tested...
  3. R

    I have questions about an electromagnet coil and the winding technique

    Hi guys, I am building an electromagnet to use mainly for its reaching properties. I want to have a large air gap. I don't care if the magnet can only lift a paper clip but I do care if it can move it from a 15 to 20 cm distance or more. I only have 1 core to work with so my choices are only...
  4. D

    Work problem on winding up a cable

    Find the work done in winding up a 300ft cable that weighs 2.00 lb /ft W=Fd W=$$\int F dx$$ My attempt w=F*D so W= (300ft)(2.00lb/ft) W=600ft.lb and $$\int_0^{300}\!\ 2xdx$$ W=90,000 ft.lb I'm taking Calc 2 and this is applied Physics problems...
  5. DiracPool

    The long and winding road that leads to your TOE

    I am hoping to get some guidance in this thread from those who have traveled the path before me. For the past couple of years I have been on a tear to educate myself in mathematical physics for a variety of reasons I won't bore you with here (some personal, some professional). In any case, to...
  6. H

    Maximizing Winding Area in Coil Design: Benefits and Considerations

    I have been reading about coil design and I have a question. Is there any specific reason a coil design should utilize the entire winding area? I keep reading about this in different literature but none of the literate i have read explains why.
  7. V

    Transformers - winding resistance and leakage reactance

    transformers -- winding resistance and leakage reactance Does anyone know what is meant by: 'determine the combined winding resistance and leakage reactance referred to the primary side'?
  8. S

    3-phase Induction Motor:Supply given to Rotor & Stator winding shorted

    In a 3 phase slip ring Induction motor, 3 phase balanced supply is given to rotor winding & stator winding is short circuited . Then rotor would - run against the direction of rotating field. Can anyone explain this phenomenon?
  9. H

    Calculating leakage inductance & winding capacitance of a step up transformer?

    I am designing a small step up transformer and I'm trying to calculate leakage inductance and winding capacitance. The problem I'm having is when I search the web I find there is a ton of info on the subject. So I have no idea where to start. Can anyone explain to me how to calculate...
  10. T

    Diagnose Copper Wire Winding Faults

    Hi. I am wondering how I can diagnose a winding and find out whether it is damaged. Windings like for solenoids or electromagnets operating on 12VDC. Or even for 12V motors. I want to know how I can detect a turn to turn shorted winding. Does an electromagnet lose magnetic power and...
  11. G

    Cycler on a winding and velocity

    Homework Statement A cycler is going through the winding, cycling on a circle of radius 6m and is slanting with alpha=75^ to the horizontal surface. What's his velocity? Homework Equations T=\frac{mv^{2}}{R} Fc=\mu F_{N} The Attempt at a Solution We have two forces on the cycler...
  12. P

    Is the Milky Way winding up or spinning out in space?

    Is the Milky Way winding up like spaghetti on a fork, or spinning out like frosting in a blender?
  13. N

    Winding Copper wire / strip on Aluminium body

    Hello All, Greetings. I am new to this forum. I am working for a heater project, in which we use plastic (PA66) over molded on aluminum (6061-T6) body for melting corrosive liquids (similar to sea water). The Aluminum body is heated by means of Positive temperature coefficient material (PTC)...
  14. R

    Is There an Insulation Monitoring Relay for Continuous Winding Monitoring?

    Does anybody know if exist a kind of Insulation Monitoring Relay, to be Online (energized) all the time and be able to monitor the Transformers and Motors Winding continuously?
  15. H

    Resonant transformer - sign of the voltage reinduced in the primary winding

    Consider a biresonant transformer with a small coupling coefficient k << 1. Let the voltage applied to the primary LC circuit be U1(t)=U*sin(2*Pi*f*t), then also the current I1 will be sinusoidal. The voltage induced in the secondary winding and the current in the secondary LC circuit will be a...
  16. H

    Coil winding direction on opposite legs?

    I am winding a transformer. I want to get it done right the first time. The transformer has a square core with a coils on opposite legs. I want the polarity to be the same on each coil so how do I wind them? Should the start of the windings be at the top of each coil? Should the...
  17. M

    Excitation winding and fuction of AVR

    I have a generator. Single phase 220 volt A.C output Frequency 50 Hz 2000 kVA Rotor winding of my generator was burnt. It was rewinded but it burnt again after 1 day. There are 2 types of windings in stator one main winding which gives 220 volt A.C output and 2nd is excitation winding...
  18. J

    Is π(L) a Submanifold of the Torus?

    I am trying to prove the following result: Fix a,b \in \mathbb{R} with a \neq 0. Let L = \{(x,y) \in \mathbb{R}^2:ax+by = 0\} and let \pi:\mathbb{R}^2 \rightarrow \mathbb{T}^2 be the canonical projection map. If \frac{b}{a} \notin \mathbb{Q}, then \pi(L) (with the subspace topology) is not a...
  19. S

    Complex anaylsis, winding number question.

    So the in the equation for the winding number/index of a curve I(\gamma, z) = \frac{1}{2i\pi} \int\gamma \frac{1}{ζ-z}dζ where \gamma : [a, b] → ℂ and z is an arbitrary point not on \gamma, what exactly does ζ represent?
  20. P

    Does the Winding Number Determine Interior Points in Complex Domains?

    Homework Statement Let D ⊂ C be open, connected, and bounded. Suppose the boundary of D consists of a finite number of piecewise differentiable simple closed curves: α0,...,αN, with α1,...,αN contained in the interior of α0. Suppose α0 is oriented in the positive direction and α1, . . . , αN...
  21. D

    MHB Proof of Winding Number 1 for Analytic $f$

    Let $f$ be analytic on an open set $U$, let $z_0\in U$, and let $f'(z_0)\neq 0$. Show that $$ \frac{2\pi i}{f'(z_0)}=\int_C\frac{1}{f(z)-f(z_0)}dz, $$ where $C$ is some circle centered at $z_0$. If I re-write the above expression, it is saying the winding number is 1, correct? I am not sure...
  22. K

    Winding resistance of large motor vs small motor

    Hi guys, I ran a large DC motor and a small DC motor for 5 minutes at max voltage/max speed. Took the readings for before running it and after running it and somehow the smaller motor after five minutes of running at max volt/max speed has more than twice the winding resistance where as the...
  23. S

    Coil Winding: How to Layer Coil Turns

    Hello everyone I have a quick question on how to wind overlapping layers of magnet wire around a coil form. How do you layer coil turns for a coil? Do you just start at the top of the coil form and then coil over the top of the previous coil in the same direction and then just twist the two...
  24. T

    DC motor armature winding question

    Hello, I am rewinding the armature for a burned up winch motor. This tutorial ( http://scootersupport.com/motorrewind.htm ) shows basically the exact same motor (but for scooters). The picture shows the armature. My question is, please help me to understand- each coil around the armature...
  25. U

    Electrical Winding 1st toroidal transformer for my DIY Geiger counter

    First post! :) I am building a Geiger counter with this circuit: http://www.pocketmagic.net/wp-content/uploads/2011/03/geiger-simple-1b.jpg in the blog the author used a regular EI transformer from a power supply, but I tried disassembling them and broke the ferrite core 4 time now, so I...
  26. H

    Bifilar Winding & Transformer Secondary Voltage

    If a transformer has a bifilar wound primary coil will the secondary voltage still be equal to the transformer's turns ratio? Bifilar coils when connected together in the proper way have a much higher voltage between turns. Instead of the voltage across each turn being equal to the total...
  27. M

    Does the direction of winding affect the induced emf in a an inductor coil?

    Hi, What if the inductor coil is wound one way rather than the other. Then the circular flow of current will be clockwise in one case and anticlockwise in the other. And if the inductor is connected to an ac source, then the current will vary. Now in both the orientations, the variation...
  28. S

    What should I know about winding a motor's coil?

    Motor winding problem please help me..? if I got a armeture of a motor without a coil and ask to wind the coil what should I know to do this and how to know whether, * it is a AC/DC motor * what gage of coil it should be * what is the ampere and voltage * how many turns should i...
  29. S

    String Theory - Winding Strings

    The answers will probably be "it ain't as simple as that" but here's trying, anyway. 1. Is current thinking that strings have to wind "around" something? If so, must the compactified space have at least one hole? 2. With just a single hole, presumably there can be just one topologically...
  30. B

    Complex log and Winding Number in Pi_1(S^1)

    Hi, everyone: I am confused about the def. of winding number of a loop on S^1 ( on elements of Pi_1(S^1,1) ). The winding number is defined by w(f):= [log(f)1)-log(f)0)]/i2Pi One of the problems is that log cannot be defined continuously on S^1, since complex logs can only be...
  31. D

    Primary winding and secondary winding wraped around a iron core

    I got a few questions about transformers.. I understand there is a primary winding and secondary winding wraped around a iron core. Now for the primary connection - take 7.2kv 1 phase line and connect it to one side of the winding and take ground (earth) to the other winding end. On the...
  32. D

    Identifying the winding that has multiple taps?

    hi guys Do you know a way of identifying the winding that has multiple taps? Do you know some material on internet that explain this better?
  33. B

    N-dimensional torus compactification and string winding

    Hello, Im trying to learn about string theory in toroidal compactification on an undergraduate level. I am mostly using Zwiebach's "A first course in string Theory" but now I am trying to do something that doesn't seem to be covered in the book or any other literature explicitly. Perhaps...
  34. K

    How to connect the winding number's definition to geometrical intuition?

    We know the winding number as a curve winds round a point.If a point is inside a closed curve,then the winding number is 1,this is the geometrical intuition. The definition of winding number of closed curve gamma with respect to a is n(\gamma ,a) = \frac{1}{{2\pi i}}\int\limits_\gamma...
  35. D

    I'm really confused about Winding Numbers in Complex Analysis

    I was hoping someone could help me understanding winding numbers For e.g. the point -i that is (0,-1) on this curve... I was trying to determine if the winding number was 2 or 3 http://img15.imageshack.us/img15/1668/11111111111111countour.jpg
  36. C

    Consider a transformer with winding ratio of 1 : 10

    Just out of curiosity : Consider a transformer with winding ratio of 1 : 10. What happens when AC 120 v is applied on primary and on secondary we apply DC voltage of 120 v from a battery source is series or in parallel? What will be the output in both cases?
  37. R

    Is Flat Wire More Efficient for Generator Windings?

    Hello all, I have a simple question about copper windings on generators. From what I have read, magnetism only penetrates the skin of a copper wire by very little. Dosnt this mean that most of the copper in a winding is wasted ? And wouldn't it be more efficient to use flat wire "-"...
  38. neduet

    What Is the Best Low-Cost Material for Generator Windings?

    Hello friends friends, which material generator coil is made and are they insulated of current but not magnat flux or can we use same wire which is used in electrical motors winding, Q:which is low cost and best material winding for generator? thanx
  39. P

    Winding your own air-core inductor

    I am trying to duplicate an already existing inductor by buying the components and winding it myself. I have found several different sources that give me different equations for determining inductance. My questions are as follow: - What is the governing equation for determining the inductance...
  40. E

    Single-phase AC motor - winding distribution

    Motor: Delco - 1/4 HP - 5.3A - 1735 RPM - single-phase AC; 32 slots - 4 poles - I have run into conflicting terminology, so I apologize for any confusion - Each of the four poles in this motor's stator core contains three coils with two empty slots at the center for a total of eight slots...
  41. Phrak

    Permanent vs. Field Winding

    This is a question about brushless DC motors. (I should have put that in the title) How do you compare the two for an single geared vehicle drive system to get the widest power band in the same package size? I've been looking over the max flux density of soft iron vs. neodymium permanent...
  42. K

    Can delta motor re-start after one winding opens?

    There is an overhead door at work that will start to open but then stops. I don't know all the details because I haven't been out to the door yet, but the information has been given to me by one of my guys. The door is driven by a 3-phase 480 volt motor. I don't know anymore information...
  43. B

    Find the resisitance of the winding at 20/60C

    Find the resisitance of the winding at 20 and 60 degrees. Information given: mass: 33.212kg Dimensons are: L=551.9291667mm W=48mm h=144mm Volume: 3814934.4mm3 Number of turns in the winding: 675 diameter of wire = 2.00mm The...
  44. S

    Help with Coil Winding for Water Fuel Cell Circuit

    I am trying to gather some info about winding inductors. This is not simple. I am trying to put together a resonant circuit to power a water fuel cell. I know a lot of people will say that this is bull but I don't care , I am having fun with it and am learning a heap. The circuit uses a bifilar...
  45. M

    Electromagnet Winding: 1200 Winds or 600 Winds?

    Hey, anybody out there good with electrical stuff?? I'm no genius but can I be correct in assuming the following? Im making high voltage electromagnets. If I use 1200 winds of awg30 magnet wire, it will have the same power ~ (EMF) Or (magnetic field strenghth) as 600 winds of awg15 magnet...
  46. A

    What is meant by winding state of a field?

    Can anybody explain what is meant by winding modes of excitation? How do such states contribute to total energy? For example, in the case of a scalar field in 2 dimensional toroidal space, how to calculate these?
  47. F

    Winding Number Proof Clarification

    I have some questions about this proof. I have numbered the equations (1), (2), ... so I can ask about them. THEOREM If the piecewise differentiable closed curve \gamma does not pass through the point a then: (1) \displaystyle\oint_{\gamma}\frac{dz}{z-a} is s multiple of 2 \pi i...
  48. T

    Calculate work when winding chain (GRE Problem 66 - Exam 9277)

    This problem is in a GRE exam which I think might have big mistake in forming the answers: A thin uniform steel chain is 10 meters long with a mass density of 2 kg per meter. One end of the chain is attached to a horizontal axle having a radius that is small compared to the length of the...
  49. D

    Strings Chan-Paton U(N) gauge symmetry fractional winding number

    I understand why in the presence of a constant vector potential A=-\frac{\theta}{2 \pi R} along a compactified dimension (radius R) the canonical momentum of a -e charged particle changes to P=p-eA. Due to the single valuedness of the wavefunction [itex]\propto e^{iPX}[/tex] P should be...
  50. V

    Winding "Hot" Armatures for HO Slot Cars

    I play around with HO slot cars and would like to wind my own "hot" armatures but I can't find any sources of direction. It seems like everyone knows how to do it so why explain:frown: I've bought a couple of pounds of mag wire in different guages but I would hate to tear up a good one to...
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