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<!DOCTYPE html>
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<title>EE568-Selected Topics in Electrical Machines</title>
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class: center, middle
# EE568-Selected Topics in Electrical Machines
## Ozan Keysan
[keysan.me](http://keysan.me)
Office: C-113 <span class="meta">•</span> Tel: 210 7586
---
# Windings of Electrical Machines
--
<img src="https://www.menzel-motors.com/fileadmin/user_upload/Service/Wicklung/motor_winding-04_web.jpg" alt="Drawing" style="width: 800px;">
### [Bobinaj](https://www.youtube.com/watch?v=qnU_AFy3ML0), [Pakistan Machine Winding Shop](https://www.youtube.com/watch?v=5YTbkETpZN8)
---
# Roles of Windings in Electrical Machines
---
# Armature Winding:
<img src="http://4.bp.blogspot.com/-lLSSvpP-1aE/UM8uxA0e5pI/AAAAAAAAAI0/6C1VMNdVKsg/s320/commutator.jpg" alt="Drawing" style="width: 400px;">
--
## Power-producing winding of an electrical machine
--
## Can be on
--
the rotor (DC machines),
--
or on the stator (synchronous machines)
---
# Field (Magnetizing) Winding:
--
## Creates the magnetic field required for energy conversion.
--
## Not all machines have a field winding (i.e. PM machines, reluctance machines)
---
# Field (Magnetizing) Winding:
## Can be on the stator: Field winding of a DC machine
<img src="http://www.gef.com.my/images/DC_Field_Coil_Winding_After_Service_Re-varnish.jpg" alt="Drawing" style="width: 500px;">
---
# Field (Magnetizing) Winding:
## Can be on the rotor: Synchronous Machine
--
## Salient Pole Rotor
<img src="http://www.kencoil.com/wp-content/uploads/2017/03/39b.jpg" alt="Drawing" style="width: 600px;">
---
# Field (Magnetizing) Winding:
## Can be on the rotor: Synchronous Machine
--
## Cylindrical Rotor
<img src="https://3.bp.blogspot.com/-yB8dCzX2duw/V4t-BfncMFI/AAAAAAAABiY/cS_7dqlDz7kVDXQtMojGfpnhFeUQ5Y4AwCK4B/s400/rotor%2Bof%2Ban%2Balternator.jpg" alt="Drawing" style="width: 800px;">
---
# Rotating Field Windings
--
### In Induction (asynchronous) machines, windings both creates field and performs energy conversion, so it is slightly differs from armature windings by definition
--
<img src="https://qph.fs.quoracdn.net/main-qimg-fb915069a5d2c4638e6e185916b77f7e" alt="Drawing" style="width: 500px;">
---
# Rotating Field Windings
## Induction Motor Rotor Side:
--
## Squirrel-Cage Rotor
<img src="https://www.researchgate.net/profile/Mohammed_Therib/publication/320799573/figure/fig1/AS:556180796657664@1509615243458/Squirrel-Cage-Rotor.png" alt="Drawing" style="width: 800px;">
---
## Squirrel-Cage Rotor
<img src="./images/ee564/copper_rotor.webp" alt="Drawing" style="width: 250px;">
<img src="./images/ee564/aluminium_rotor.jpg" alt="Drawing" style="width: 450px;">
### Can be made from copper or aluminium. Coil ends are short-circuited.
---
# Rotating Field Windings
## Wound Rotor Induction Machine
--
<img src="https://www.industrial-electronics.com/images/imc7e_44-1.jpg" alt="Drawing" style="width: 600px;">
---
# Damper Winding
--
<img src="./images/ee564/damper_winding.png" alt="Drawing" style="width: 550px;">
## [What is it used for](https://instrumentationtools.com/damper-windings-used-synchronous-motors/)?
---
# Damper Winding
<img src="https://engineeringtutorial.com/wp-content/uploads/2016/04/Electrical-Machines.jpg" alt="Drawing" style="width: 500px;">
### Helps to self-start of a synchronous machine and Reduces oscillations in transient conditions.
### [61MVA Stator & Rotor Rewinding](https://www.youtube.com/watch?v=ov8KAjxMxlU), [coil manufacturing](https://www.youtube.com/watch?v=Y7T6I1wg7tQ)
---
# Other Windings
## Helps to reduce armature reaction
- ## [Commutating Windings](http://www.studyelectrical.com/2015/01/compensating-windings-interpoles-dc-generator-motor.html)
- ## [Compensating Windings](https://www.quora.com/Electrical-Machines-What-do-interpoles-do-in-DC-motors) (Interpoles)
---
# Winding Types
<img src="./images/ee564/winding_types.png" alt="Drawing" style="width: 700px;">
---
# Exercise
--
## Field Winding of a Salient Pole Synchronous Machnie
<img src="./images/ee564/synchronous_salient.png" alt="Drawing" style="width: 800px;">
#### Calculate the required field winding current to get Bmax=0.82T, if there are 95 turns per pole. Assume sinusoidal flux density distribution and the minimum airgap distance is 3.5mm
---
# Exercise
<img src="./images/ee564/field_exercise.png" alt="Drawing" style="width: 800px;">
---
# Slot Windings
--
<img src="./images/ee564/slot_winding_current_linkage.png" alt="Drawing" style="width: 800px;">
### Current Linkage distribution in a two-pole cylindrical winding.
#### \\(z_Q\\) conductors in each slot with current \\(I_f\\)
---
### Some Definitions
--
## Pole Pitch:
--
## \\(\tau_p = \dfrac{\pi D}{2p} \\)
###\\(p\\): pole pairs, \\(D\\): air-gap diameter
---
### Some Definitions
## Slot Pitch:
--
## \\(\tau_u = \dfrac{\pi D}{Q} \\)
###\\(Q\\): number of slots
--
## Slot Angle (electrical):
--
### \\(\alpha_u = \dfrac{2\pi}{(Q/p)} \\)
---
### Some Definitions
## Slots per-pole per-phase (q):
--
## \\(q = \dfrac{Q}{2pm} \\)
###\\(m\\): number of phases
---
### Some Definitions
## Slots per-pole per-phase (q):
## If \\(q\\) is integer:
--
Integral Slot Winding
--
## If \\(q\\) is fractional:
--
Fractional Slot Winding
---
# 3-Phase Integral Slot Stator Winding
--
## Simplest case for rotating MMF
- ## m = 3
- ## p = 1
- ## q = 1
--
- ## Q = 6
---
## Simplest case:
<img src="./images/ee564/slot_q6.png" alt="Drawing" style="width: 500px;">
---
## MMF from a single phase
--
<img src="./images/ee564/single_slot_mmf.png" alt="Drawing" style="width: 700px;">
--
## Peak MMF: \\(\dfrac{4}{\pi}\dfrac{i_U z_Q}{2}\\)
---
## MMF from three phase
<img src="./images/ee564/3ph_mmf1.png" alt="Drawing" style="width: 700px;">
---
## MMF from three phase
<img src="./images/ee564/3ph_mmf2.png" alt="Drawing" style="width: 750px;">
---
# Three Phase AC: Rotating MMF
<img src="http://www.ece.umn.edu/users/riaz/animations/sinwaves0.gif" alt="Drawing" style="width: 750px;"/>
---
# Three Phase AC: Rotating MMF
<img src="http://www.ece.umn.edu/users/riaz/animations/vecmovieslow.gif" alt="Drawing" style="width: 500px;"/>
---
# Three Phase AC: Rotating MMF
<img src="http://www.ece.umn.edu/users/riaz/animations/sinvec.gif" alt="Drawing" style="width: 800px;"/>
### Derivation left as an exercise!
---
## Manufacturing of Coils
<img src="https://en.partzsch.de/files/Produktspektrum/Staenderwicklungen/Formspulen/galerie/formspulen_6.jpg" alt="Drawing" style="width: 300px;"/>
### Chevy Spark EV [Motor Manufacturing](https://www.caranddriver.com/news/a18744950/we-build-the-chevy-spark-evs-ac-permanent-magnet-motor/)
### [Disributed winding schematic](https://www.researchgate.net/profile/Jakob_Igelspacher/publication/241174581/figure/fig3/AS:340780838342662@1458259891354/Fig-4-Schematic-example-of-a-distributed-winding-of-an-axial-flux-induction-machine.jpg)
### [Preformed coils](https://www.heinrich-schuemann.de/ankerformspulen-200.html), [Preformed coils-2](https://www.heinrich-schuemann.de/files/uploads/Produkte/Elektromaschinenbau/ankerformspulen/anker-w1p.jpg)
### [Coils in the stator](https://empoweringpumps.com/sulzer-hydro-generator-refurbishment-increases-output-by-15/), [Coils in the stator-2](https://4.imimg.com/data4/YY/YY/GLADMIN-/wp-content-uploads-2015-11-diamond_coils_03-500x500.jpg)
---
# Distributed Winding
### Many coils are connected in series and distributed over many slot to achine a more sinusoidal MMF distribution
--
<img src="https://raw.githubusercontent.com/ozank/ozank.github.io/master/presentations/images/distributed_coil.png" alt="Drawing" style="width: 400px;"/>
---
# Distributed Winding MMF
### Let's calculate the MMF with the distributed coil:
--
<img src="https://archive.cnx.org/resources/8cbc00b4366fcb581988511a2b55b5bdee858576/graphics14.png" alt="Drawing" style="width: 600px;"/>
---
# Distributed Winding Manufacturing
###Videos
- [Production of electric machines](https://www.youtube.com/watch?v=5Mu42TzHy8M) (T=6:00)
- [Rewinding a Large Motor](https://www.youtube.com/watch?v=_65mXQ-GNVM) (T=0:20)
- [BMW Electric Motor - Drive](https://www.youtube.com/watch?v=Qktx5yx1Bjw)
- [Induction Motors: Overhauling a Motor](https://www.youtube.com/watch?v=yPvYd03cKJU)
---
## Full-Pitch Coil ?
--
<img src="https://www.electrical4u.com/wp-content/uploads/2013/04/full-pitched-short-pitched-winding-11.10.13.png" alt="Drawing" style="width: 800px;"/>
---
## Full-Pitch Coil ?
<img src="./images/full_pitch.png" alt="Drawing" style="width: 700px;"/>
### (a)Full-pitched coil, (b) Short-pitched coil
---
# Winding Factors
### Constants related to estimate characteristics of MMF and voltage of windings.
### An easier method for analytical calculations
--
- ## Distribution Factor (\\(k_d\\))
--
- ## Pitch Factor (\\(k_p\\))
---
# Distribution Factor
<img src="https://raw.githubusercontent.com/ozank/ozank.github.io/master/presentations/images/distributed_coil.png" alt="Drawing" style="width: 500px;"/>
---
# Distribution Factor
## Vector sum of voltages in a distributed coil is less than the algebraic sum of the voltage in each coil.
--
## \\(k_d = \dfrac{\mathrm{Vector\,Sum\,of\,Voltages}}{\mathrm{Algebraic\,Sum\,of\,Voltages}}\\)
---
# Distribution Factor
### Q1: What is the distribution factor of a concentrated coil?
--
### Q2: What is the distribution factor of two coils seperated by \\(\pi/3\\)?
--
### Q3: What is the distribution factor of three coils seperated by \\(\pi/6\\)?
--
### Generalized equation
---
# Distribution Factor
## \\(k_d = \dfrac{sin(q \dfrac{\alpha}{2})}{q sin(\dfrac{\alpha}{2})}\\)
## \\(q\\): Number of coils
## \\(\alpha\\): Angle between each coil
---
# Pitch-Factor
--
## Review of Definitions:
- # Full-pitched (= \\(\pi\\) electrical)
--
- # Under-pitched (< \\(\pi\\) electrical)
--
- # Over-pitched (> \\(\pi\\) electrical)
---
## A 2-pole machine with sinusoidal \\(B_{gap}\\)
<img src="https://raw.githubusercontent.com/ozank/ozank.github.io/master/presentations/images/2pole_mmf.jpg" alt="Drawing" style="width: 450px;"/>
---
## A 2-pole machine with sinusoidal \\(B_{gap}\\)
<img src="https://raw.githubusercontent.com/ozank/ozank.github.io/master/presentations/images/2pole_voltage.jpg" alt="Drawing" style="width: 800px;"/>
---
# Full-pitched vs Fractional-pitched Coil
- ## Full-pitch = 180 degrees (\\(\pi\\))
--
- ## Under pitch < 180 degrees (\\(\pi\\))
--
- ## \\(V\_{full-pitch} > V\_{under-pitch}\\)
--
- # If so, what is the point?
---
# A big Parenthesis
## Fourier Series
--
> ## All waveforms, no matter what you scribble or observe in the universe, are actually just the sum of simple sinusoids of different frequencies.
---
# Fourier Series
[Fourier Series using Circles](https://www.youtube.com/watch?v=LznjC4Lo7lE), [Complex Orbits](https://www.youtube.com/watch?v=QVuU2YCwHjw), [Useful applets](http://www.falstad.com/fourier), [Fourier examples](http://ptolemy.eecs.berkeley.edu/eecs20/week8/examples.html)
[More Useful Links on Fourier Series](http://keysan.me/explained/)
---
# Fourier Series
<a href="https://www.google.com/search?q=plot+(sin(x)%2B0.25*sin(3*x)%2B0.1*sin(5*x))">Google Plot</a>
--
- ## Let's see what happens with a 2/3 under pitched coil?
--
- ## Under-Pitched coils are very useful for the elimination of harmonics
---
#Pitch Factor
## Voltage in a short-pitched coil is less than a full-pitched coil
## \\(k_p = \dfrac{\mathrm{Short-Pitched\;Coil\;Flux}}{\mathrm{Full-Pitched\;Coil\;Flux}}\\)
---
#Pitch Factor
# \\(k_p = sin(\dfrac{\lambda}{2})\\)
# \\(\lambda\\): Coil-pitch in electrical degrees
---
# Pitch and Distribution Factor for Harmonics
## For harmonic number n:
## \\(k_p(n) = sin(\dfrac{n\lambda}{2})\\)
--
## \\(k_d(n) = \dfrac{sin(q n \dfrac{\alpha}{2})}{q sin(\dfrac{n\alpha}{2})}\\)
---
# Winding Factor:
## is the combination of distribution and pitch factor
--
#\\(k_w = k_d \times k_p\\)
--
## gives an idea about the magnitude of the coil voltage (or MMF) compared to concentrated and full-pitched winding.
---
# Group Exercise
--
### A rotating magnetic flux created by a 3-ph 50 Hz, 600 rpm alternator has a distribution of magnetic flux density:
--
### \\(B(\theta)=\hat{B}_1 sin(\theta)+\hat{B}_3 sin(3\theta)+\hat{B}_5sin(5\theta)\\)
--
### \\(B(\theta)=0.9sin(\theta)+0.25 sin(3\theta)+0.18sin(5\theta)\\)
---
# Group Exercise
## The machine has:
- ### 180 slots, double-layer winding, Y-connected
--
- ### Each coil has 3 turns with a span of 15 slots
--
- ### Armature diameter = 135 cm
--
- ### Effective axial length = 0.5 m
---
# Group Exercise
--
## Draw the winding diagram
--
## Calculate the MMF for:
--
- ### ia=1 A, ib=-0.5 A, ic=-0.5A
--
- ### ia= -0.5A, ib=1 A, ic=-0.5A
---
# Group Exercise
## Calculate:
--
- ## Number of poles, pole area
--
- ## Fundamental flux per-pole
--
- ## Winding and distribution factors for each winding
--
- ## Induced voltage rms per phase and line-to-line
---
## Now find the RMS of phase voltage and line voltages.
--
### \\(V\_{rms(i)} = \dfrac{1}{\sqrt{2}} 2\pi f\_i k\_{w(i)} N\_{ph} \Phi\_{(i)} \\) which is equal to:
--
### \\(V\_{rms(i)} = 4.44 f\_i k\_{w(i)} N\_{ph} \Phi\_{(i)} \\)
### \\(i\\): harmonic order, \\(\quad f\\): frequency
### \\(k_w\\): winding factor
### \\(N_{ph}\\): number of coils per phase
### \\(\Phi\\): flux per pole.
---
# True RMS
### RMS values of all harmonics
# \\(\sqrt{\sum{V_{rms-i}^2}}\\)
### For fundamental, 3rd and 5th harmonics
# True RMS = \\(\sqrt{V\_{1}^2+V\_{3}^2+V\_{5}^2}\\)
---
# Induced Voltages
## V1=4482 V
## V3=613 V
## V5=49.5 V
## Waveform of the [total phase voltage](https://www.google.com.tr/search?ei=67W3WqSJDMOv6ATzqZ_QDQ&q=plot+4482*sqrt%282%29*sin%28x%29+-+613*sqrt%282%29*sin%283*x%29+%2B+49.5*sqrt%282%29*sin%285*x%29&oq=plot+4482*sqrt%282%29*sin%28x%29+-+613*sqrt%282%29*sin%283*x%29+%2B+49.5*sqrt%282%29*sin%285*x%29&gs_l=psy-ab.3...10186.25518.0.26977.18.18.0.0.0.0.317.2643.0j12j3j1.16.0....0...1c.1.64.psy-ab..2.0.0....0.DBXGbFsm7D8)
---
# Line Voltage
## \\(V\_{BA}=V\_{Bn}-V\_{An}\\)
## No 3rd Voltage Harmonics in Y-connected line-to-line voltages
## Waveform of the [line voltage](https://www.google.com.tr/search?ei=R7a3WoqpNszO6AS415iIDg&q=plot+4482*sqrt%286%29*sin%28x%29+%2B+49.5*sqrt%286%29*sin%285*x%29&oq=plot+4482*sqrt%286%29*sin%28x%29+%2B+49.5*sqrt%286%29*sin%285*x%29&gs_l=psy-ab.3...4540.15170.0.25670.9.9.0.0.0.0.179.1246.0j9.9.0....0...1c.1.64.psy-ab..0.0.0....0.8eSFbs9SpcI)
---
# Fractional Slot Windings
--
### Slots-per-pole-per-phase (q) is fractional
--
- ### Gives more choice in winding design
--
- ### Voltage waveform can be improved by eliminating certain harmonics
--
- ### Vast possibilities, but not every possibility produces a symmetrical rotating MMF
---
## Fractional Slot Example
--
## Consider a 10-pole machine
--
## What can be the number of slots?
--
- ## 30 slots? q=
--
1
--
- ## 60 slots? q=
--
2
- ## How about 42 slots?
--
## q = 42/(10*3) = 7/5
---
## 42 slot, 10 pole
<img src="./images/ee564/42_slot.png" alt="Drawing" style="width: 500px;">
---
## 42 slot, 10 pole
## Phase shift between coils?
--
### \\(360*(10/2)/42=42.85^o\\)
--
### Let's choose a coil span of 4 slots. Coil pitch?
--
### \\(42.85*4 = 171.5^o\\), Pitch factor?
--
### \\(sin(171.5/2) = 0.997\\)
---
# Why Fractional Winding?
## Integer Slot: 4 pole, 12 slot
<img src="./images/ee564/4pole_12slot.png" alt="Drawing" style="width: 500px;">
---
# Why Fractional Winding?
## Can you guess the magnitude of cogging torque?
<img src="./images/ee564/4pole_12slot.png" alt="Drawing" style="width: 500px;">
---
# Why Fractional Winding?
## Can you guess the magnitude of cogging torque?
<img src="./images/ee564/4pole_12slot_flux.png" alt="Drawing" style="width: 500px;">
---
# How can you reduce cogging torque?
## Skewing is an option, but increases phase resistance
<img src="./images/ee564/skewed_stator.png" alt="Drawing" style="width: 700px;">
---
# Why Fractional Winding?
## Repeat the same thing with 4 pole, 15 slot?
<img src="./images/ee564/4pole_15slot.png" alt="Drawing" style="width: 500px;">
---
# Why Fractional Winding?
## Even more poles: 10 pole, 12 slot?
<img src="./images/ee564/10pole_12slot.png" alt="Drawing" style="width: 500px;">
---
## Conditions for Symmetrical Rotating MMF
--
### 1- Number of coils per phase winding should be an integer
--
### Single-layer windings:
### \\(\dfrac{Q}{2m} = pq \in N\\)
--
### Double-layer windings:
### \\(\dfrac{Q}{m} = 2pq \in N\\)
### Easier to achieve symmetrical MMF with double-layer windings
---
## Conditions for Symmetrical Rotating MMF
--
### 2- The angle between phase windings (\\(\alpha\_{ph}\\)) should be an integer multiple of slot angle \\(\alpha_z\\)
--
### Normal Systems:
### \\(\dfrac{\alpha\_{ph}}{\alpha\_{z}}=\dfrac{Q}{mt} \in N\\)
### t: largest common divider of Q and p
### Reading Assignment Pyrhonen Sections 2-9:2-12
---
# Winding Voltage Phasor Diagrams
<img src="./images/ee564/voltage_phasor.png" alt="Drawing" style="width: 500px;">
---
# Voltage induced in a straight wire?
<img src="http://www.solitaryroad.com/c1048/ole3.gif" alt="Drawing" style="width: 450px;">
---
# Voltage induced in a straight wire?
# \\(e = Blv\\)
## v: linear velocity
---
# Winding Voltage Phasor Diagrams
## 2 pole, 3phase, 12 slot machine
--
<img src="./images/ee564/voltage_phasor_12slot.png" alt="Drawing" style="width: 800px;">
---
# Winding Voltage Phasor Diagrams
## Induced Phase Voltages
--
<img src="./images/ee564/voltage_phasor_phase.png" alt="Drawing" style="width: 800px;">
---
## Two possible ways to put the coils
--
## Lap winding
--
<img src="./images/ee564/lap_winding.png" alt="Drawing" style="width: 750px;">
### Most common type
---
## Concentric winding
--
<img src="./images/ee564/concentric_winding.png" alt="Drawing" style="width: 400px;">
### They have exactly the same voltage waveforms
---
## Fractional Slot Example:
--
## 12 slot, 10 pole, single layer
--
<img src="./images/ee564/12slot_10pole.png" alt="Drawing" style="width: 400px;">
---
## Fractional Slot Example:
--
### \\(\alpha_u=\\)
--
\\(360*5/12=150^o\\)
--
<img src="./images/ee564/12slot_10pole2.png" alt="Drawing" style="width: 400px;">
---
## Fractional Slot Example:
### Phase Induced Voltage
<img src="./images/ee564/12slot_10pole3.png" alt="Drawing" style="width: 800px;">
---
## Example (2-16)
### Create a voltage phasor diagram of a single layer integral slot winding for which Q=36, p=2, m=3
--
<img src="./images/ee564/voltage_phasor_ex.png" alt="Drawing" style="width: 450px;">
---
## Example (2-16)
### Create a voltage phasor diagram of a single layer integral slot winding for which Q=36, p=2, m=3
<img src="./images/ee564/voltage_phasor_ex2.png" alt="Drawing" style="width: 800px;">
---
## Fractional Single Layer vs Double Layer
# Q=6, m=3, p=2, q=1/2
--
<img src="./images/ee564/fractional_single_double.png" alt="Drawing" style="width: 750px;">
---
# Winding Examples
---
<img src="./images/ee564/winding_ex1.png" alt="Drawing" style="width: 500px;">
--
## Q=24, p=2,
--
q=2,
--
Single layer,
--
integral slot, distributed winding
---
<img src="./images/ee564/winding_ex2.png" alt="Drawing" style="width: 500px;">
--
## Q=12, p=2,
--
q=1,
--
Single layer,
--
integral slot, concentrated winding,
---
<img src="./images/ee564/winding_ex3.png" alt="Drawing" style="width: 500px;">
--
## Q=18, p=2,
--
q=3/2,
--
Double layer,
--
fractional slot winding,
---
<img src="./images/ee564/winding_ex4.png" alt="Drawing" style="width: 500px;">
--
## Q=6, p=2,
--
q=1/2,
--
Double layer,
--
fractional slot concentrated winding,
---
<img src="./images/ee564/winding_ex5.png" alt="Drawing" style="width: 500px;">
--
## Q=6, p=2,
--
q=1/2,
--
double layer,
--
fractional slot, concentrated winding,
---
# Winding Factor Tables
## Single Layer Winding
<img src="./images/ee564/winding_table_single.png" alt="Drawing" style="width: 800px;">
---
# Winding Factor Tables
## Double Layer Winding
<img src="./images/ee564/winding_table_double.png" alt="Drawing" style="width: 800px;">
---
# Winding Factor Tables
### Online Calculators
<img src="https://pengky.cn/zz-generator-principle-and-structure/06-ac-motor-winding/10-ac-motor-winding.jpg" alt="Drawing" style="width: 400px;">
- ### [Emetor](https://www.emetor.com/windings/)
- ### [Winding Scheme Drawer](https://www.bavaria-direct.co.za/scheme/calculator/)
---
# Winding Manufacturing
## Slot Layout
--
<img src="./images/ee564/slot_layout.png" alt="Drawing" style="width: 600px;">
---
# Random Wound Coils
<img src="./images/ee564/random_wound_coil.png" alt="Drawing" style="width: 800px;">
### [Random wound coil insertion](https://www.youtube.com/watch?v=5P6YVi2mB6Q)
---
# Form Wound Coils
<img src="./images/ee564/form_wound_coil.png" alt="Drawing" style="width: 800px;">
### [Enercon Generator](https://www.youtube.com/watch?v=MgGk2WvK80M), (8:28)
---
# Form Wound Coils
- ### [Preformed Coil Manufacturing](https://youtu.be/qQ2pS_z3dVc?t=215)
- ### [Coil Spreader](https://www.youtube.com/watch?v=TnKKFZAD2uY)
- ### [Hair Pin Winding Manufacturing](https://youtu.be/fT04LbFXR7E?t=65)
---
# Semi-closed vs Open Slot
<img src="./images/ee564/open_slot.png" alt="Drawing" style="width: 500px;">
---
# Fill Factor Comparison
--
## Random Wound Coil
<img src="./images/ee564/fill_factor_random.png" alt="Drawing" style="width: 500px;">
---
# Fill Factor Comparison
## Form Wound Coil
<img src="./images/ee564/form_wound.png" alt="Drawing" style="width: 450px;">
### Up to 65% fill factor (higher possible with lower voltages)
---
# Fill Factor Comparison