oneTesla User Manual
Contents
1. o DO DOP Fe Re re DO re re FRE DR RR Rey Re ey Rey Re Co NI FE rS DO O DO H Aluminum tape 1 roll 36 AWG magnet wire 1 spool 6 1 o 0 C CG A Q 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Assembly Instructions Driver socke Instal Instal Install IC1 the 74HC14 inverter To do so install a 14 pin IC socket then install the IC itself in the t Be sure to take note of the location of the notch on the IC Install IC2 the 74HC74 flip flop Install IC3 the UCC37321 gate driver Install IC4 the UCC37322 gate driver 1 C1 a 100 nF capacitor Install C4 a 1 uF capacitor Install C5 a 1 uF capacitor 1 C6 a 1 uF capacitor Install C7 a 1 uF capacitor Install C8 a 1 uF capacitor Instal 1 C11 a 1 uF capacitor Install C13 a 1 uF capacitor Instal Instal 1 C14 a 1 uF capacitor 1 C16 a 1 uF capacitor Install C17 a 330 pF capacitor Install R4 a 1Kohm resistor Instal 1 R5 a 1OKOhm resistor Install R6 a 2000hm resistor Install R7 a 6000 hm resistor Install R8 a 100KOhm resistor Install D1 a 1N4148 diode Take care to note the polarity as indicated by the band on the silkscreen Install D2 a 1N4148 diode Install JP1 a 2 pin jumper Install the DC power j2. for updates and exciting new products For those of you into the design aspects of the coil EAGLE PCB and schematic files are available on our website as well 12 A EAGLE circuit board o CURRENT TRANSEORMER OHSOSNGH HI QWSGONG HO4 Ea RE N 0 KN K ya NA Ne 00 ATUWEAN TStueg buem f i r neg ATAR QT UOISISA PS S V Iar ggnt Ep GE ness as 94 C3 S68K F A68uF 30Q000U CDE B Schematic Diagram ano E aso 25d NP TS TPL 82935 3 3 Sct ni uN E y oL xX Vveoas NOT pe aL no d 0001 o 8 Ares L P wg ef 2 gin 81535 is so oH z 3 9 89 2 ku 5 pE s NETS Te ano 3191 NETS TZ m m SA OA Nezsipz ONO ji ae 9791 ala xia 3 8 n SS P L ga NkTSTF2 ES 19 N 2 ss oF TT V 991 sal Y azo 8131 14 C 1 Glossary Tank Circuit A high Q LC circuit Q refers to the quality of the circuit i e the rate at which it loses energy In an ideal tank circuit energy sloshes between the capacitor and inductor without ever being lost or used It can be thought of as water sloshing between two containers Pinging Colloquial term for stepping the capacitor voltage in an LC tank circuit This results in sinusoidal oscillations at the resonant frequency Topload The often to
3. is an air cored resonant transformer It develops a high voltage at its output terminal via a combination of two mechanisms transformer step up action and resonant rise across the output Unlike a standard transformer a Tesla coil has no magnetic core The benefits of this are twofold Firstly it reduces the chances of secondary arc over there is no core to arc to Even more importantly the equivalent volts per turn of a Tesla coil can be hundreds or thousands of volts per turn Any magnetic material would saturate at this many volts per turn so air is the only option cI R1 O i L1 Figure 1 Simplified Tesla Coil Model The AC source drives a primary coil at the resonant frequency of the secondary coil modeled by L1 C1 and R1 R1 represents the parasitic resistance of the secondary coil and C1 is the intrinsic capacitance between the windings of the coil plus that of the topload Because of transformer action on the secondary side it looks like we are driving the RLC tank with a higher voltage Furthermore because we are driving the tank at its resonant frequency C1 develops a high peak voltage determined by the value of R1 It is this peak voltage that determines the spark length Different Tesla coils differ in how the driving voltage across L1 is developed In a spark gap Tesla coil it derives from the oscillations that occur after pinging a resonant tank circuit In a classical solid state Tesla coil it is
4. the IC Instead the UCC3732x chips which have high power output stages capable of sourcing 9A for brief pulses buffer the drive signal The gate drive transformer provides isolation for the high side signal which is referenced to the collector of the low side transistor This means when the high side transistor turns on its gate needs to be charged to 355V with respect to ground A transformer provides a convenient way to do this Diodes D3 D4 and capacitors C9 and C10 form a voltage doubling rectifier to supply 340V to the half bridge for better spark performance versus undoubled rectified mains Now that you hopefully understand how a Tesla coil works lets start building 5 Kit Contents Part Quantity UCC37321 UCC37322 74HC14 74HC74 14 pin IC socket 8 pin IC socket Toroidal Core FGH60N60SMD Trifilar 24AWG wire 2 5 OD PVC Tubing 10 3 5 OD PVC Tubing Extruded heatsink 4 40 Screws 8 32 Screws 8 32 Nuts Thermal Pad 1KOhm 5W Power Resistor Current Transformer 1000 uF 250V capacitor 1000 uF 16V capacitor luF 100V capacitor 100 nF 50V capacitor 330 pF 100V capacitor 100KOhm 1 4W resistor 10KOhm 1 4W resistor 600 Ohm 1 4W resistor 200 Ohm 1 4W resistor 6 8 Ohm 1 4W resistor LM7815 IC LM7805 IC Fiber optocoupler 3 5mm LED 2 pin jumper 3 prong AC jack 2 5x5 5mm DC jack 1N4148 diode MURA60 diode Inner tube Q NINI N N A
5. Only Toroid Assembly 9 Primary Dimensions 2 y iiet lee oe ed dk e ee ie UWA 10 1 Before You Begin Congratulations on your purchase of a oneTesla kit oneTesla is a coil designed to perform well while being simple for beginners to build flexible efficient and cost effective to maintain and repair It is an ideal introductory platform for beginning coilers as well as an excellent Tesla coil for more advanced users seeking a small portable coil In the following text bold indicates a technical term that can be found in the Glossary 2 WARNINGS 1 Never touch the output of the Tesla coil it is extremely dangerous and may cause serious injury or death High frequency RF output can cause painful deep skin burns 2 Users of pacemakers or other electronic medical implants should not use this kit EMI emitted by the coil may interfere with implant function causing death 3 Wear safety goggles at all times when operating the Tesla coil Power semiconductors may overheat and fail violently causing a shrapnel hazard 4 Energy storage capacitors on the board will remain charged for up to 5 minutes after powering down the coil Do not attempt to service the coil until sufficient time has passed Furthermore it is advised to use a multimeter to measure voltage across the capacitors before servicing Failure to do so may cause serious injury or death 3 Introduction to Tesla Coil Operation A Tesla coil
6. a high frequency DC AC inverter with a peak voltage of perhaps 400V However with such a low peak voltage versus the 10KV of a spark gap coil spark performance is hindered A double resonant solid state Tesla coil DRSSTC remedies this problem by putting a capacitor in series with the primary C2 R1 C1 12 L1 Figure 2 Simplified DRSSTC model The AC voltage source here is still a DC AC inverter It drives a LC tank at resonance leading to high voltages developed across L1 as in a spark gap coil Because of the phase difference between the voltages across the tank capacitor and primary the inverter always only sees say 400V across it Because of resonant effects the inverter has to source tremendous current since the current through the inverter is Vi1 27fLI1 and we want Vr1 to be large However semiconductor power switches such as MOSFETs and IGBTs are well suited to conducting very high pulsed currents oneTesla uses IGBTs rated for 60A continuous operation but operates happily at over 300A In oneTesla the inverter is implemented as a half bridge C1 S1 u 3 v c2 s2 Figure 3 Half bridge Inverter When S1 is closed the load primary circuit sees Vi 2 volts across it When S2 is closed the load sees V 2 volts The advantage of using a double resonant circuit is that the transistors only need to be rated for V1 volts MOSFETs and IGBTs rated for 600V operation are quite common and can be c
7. ack PJ 037B Instal the fiber optocoupler Make sure the mounting pins are aligned with the holes in the board Install IC5 the LM7815 regulator Install IC6 the LM7805 regulator Install the 1KOhm 5W resistor Install C2 a 1000 uF 16V capacitor Be sure to note the polarity Instal 1 C15 a 1000 uF 16V capacitor Install C3 a 1000 uF 16V capacitor 6 2 High frequency Inverter Begin by tinning the traces running from the power jack to the bridge and from the bridge to the tank capacitor Then 1 Install U3 a FGH60N60SMD IGBT Install U4 a F H60N60SMD IGBT Install D3 a MUR460 diode Be sure to note polarity Install D4 a MUR460 diode Be sure to note polarity Install the current transformer an Ae V N Solder a 14 AWG jumper wire between the pads Pl and P2 The jumper should pass through the center of the current transformer N Install the 3 terminal AC inlet 8 Install the 2 terminal terminal block for the output 9 Install the CDE940 film capacitor 10 Install C9 a 1000 uF 250V capacitor Be sure to note polarity 11 Install C10 a 1000 uF 250V capacitor 12 Install R2 a 6 8Ohm resistor 13 Install R3 a 6 8Ohm resistor 14 Tape some polyamide tape over the bottom of the heatsink 15 Place a piece of thermal pad on the tab of each IGBT and screw the IGBT s onto the heatsink using the included 4 40 screws 6 3 Gate Drive Transformer Twist the three st
8. dred hertz If no signal is present makes sure that the ON time setting on the interrupter is not zero If you do not have an oscilloscope raise the pulsewidth to a nonzero setting and listen for a faint buzzing sound from the GDT Verify that none of the IC s are hot to the touch Hot voltage regulators are normal Step 2 Primary only testing Connect the primary to the driver by screw the end terminals to the terminal block With the logic unplugged plug in the main power cord Verify that nothing happens UNPLUG the main power and wait for the bus capacitors to bleed approximately 5 minutes Plug the logic in MAKE SURE THAT THE MAIN POWER IS UNPLUGGED AND THE BUS CAPACITORS ARE DISCHARGED If you have not done so already connect the interrupter to the driver using the fiber cable Set the switch on the interrupter to Manual mode and turn the ON time knob to zero If you have a variac complete the next steps with the main power plugged in to the variac Plug the main power cord in Turn up the ON time knob slightly You should hear a faint buzzing sound from the primary 10 10 11 12 8 3 o n 9 If you own an oscilloscope you can confirm that the primary current waveform is behaving appro priately Make a current transformer by winding 50 turns of wire on the included toroidal core and soldering a 3Ohm resistor across the loose ends Feed the primary wire through the ce
9. heaply ob tained MOSFETs rated for high primary voltages are extremely expensive and have non ideal characteristics The transistors in the inverter have to carry upwards of 300A In order to prevent the bridge from overheating it is necessary to pulse the inverter on and off using an interrupter Furthermore it is necessary to insure that the inverter switches when the tank current is zero to reduce switching losses in the transistors The control circuit described in the next section insures this 4 Summary of Circuit Operation The current transformer samples the primary current waveform which is clamped by diodes D1 and D2 to the 5V rail The 1K power resistor insures the diodes do not have to carry excessive current This clamped signal is then fed into the input of IC1 a 74HC14 producing a buffered clock signal for the D type flip flop IC2 1C2 insures that the interrupter signal which comes from the optocoupler only turns off the inverter at the zero crossings of the current waveform which happen to be the edges of the clock signal from the 74HC14 The output of the 74HC14 also drives the inputs of IC3 and IC4 UCC37321 2 gate drive IC s A power IGBT does not have an ideal gate its gate has some capacitance which needs to be charged to operating voltage If we were to drive these gates directly with the output of the flip flop the gate capacitor would behave like a short when uncharged and draw enough current to destroy
10. ilers the merrier right 16
11. nter of the toroid and scope the voltage across the resistor It should be a clean sinusoid of steadily rising amplitude If you do not hear a buzzing sound from the primary swap the positions of the UCC37321 and UCC37322 If no output is present check for broken solder joints in the controller Do not replace the transistors except as a last resort it is exceedingly unlikely that brand new IGBT s will be damaged Step 3 Spark testing Center the secondary inside the primary feeding the loose wire at the bottom through The AC power jack has a tabbed ground terminal At this point use some sandpaper to remove the enamel from the loose non toroid end of the secondary and solder or alligator clip it to the ground tab as you feel appropriate Unplug the main power cord Plug in logic Connect the interrupter setting ON time to zero Plug in the main power cord making sure the ON time is still zero SLOWLY turn up the ON time knob There should be visible discharge at a very low setting If no sparks appear DO NOT increase the ON time further First reverse the positions of the UCC gate drive IC s If that does not work check for loose solder connections incorrectly placed components or backwards components in the case of diodes and electrolytic capacitors Also verify that the GDT is connected appropriately note the position of the marked wires Optimization At this point you should have a functioning Te
12. oneTesla User Manual EvolutionWabbit Incorporated July 24 2012 Contents 1 Before You Begin 2 WARNINGS 3 Introduction to Tesla Coil Operation 4 Summary of Circuit Operation 5 Kit Contents 6 Assembly Instructions Goll Driver au aru Set S a on eee Gn ee A Oh ee a eg Bee a u 6 2 High frequency Inverter 6 3 Gate Drive Transformer css 2 2b bea EE REE ee ee ee ana A Q ud 6 4 Tesla Coll Secondary i fx cov seine be ae a ua Roe ar ee ate a h pk Se a ed 7 Primary Coil 8 Assembly and Troubleshooting 8 1 Step 1 Verify Logic Functionality 8 2 Step 2 Primary only testing 83 Step 33 Spark testing a dad AA PE AA A 9 Optimization 6 5 Toroidal topload 10 Maintenence 11 Conclusion A EAGLE circuit board B Schematic Diagram C Glossary D Copyright and Licensing O 00000 10 10 10 10 11 11 12 12 13 14 15 16 List of Figures MONGOO EN Simplified Tesla Coil Model wima ci aori qa qosa S ase a a sue a ee 4 Simplified DRSSTC model aa d b ee ee 5 Halt bridge Inverter a asin isnt Alb ana ka h a BOR a Bee sel Ta los Be da 5 EDT Constructions at iris os et OG S y ae a an S A EN a S su Bh ha 2 8 Secondary Dimensions ppa ti Fe S suk aku we Pe ee a ne Ah el A 9 Toroid Assembly 22 2 yy tate So Biche Poke O Bg Rob mas A ee a ele Be es 9 Pro Ultra Kit
13. onnect the driver board to the primary coil as described in Spark Testing above Make sure there is a current transformer installed on the primary as described in Primary only testing Power on the coil preferably with a variac if you have one scope the voltage across the current transformer and examine the frequency of the sinusoidal oscillations If this frequency is lower than the resonant frequency measured in the previous step remove primary turns If it is greater add primary turns 10 Maintenence To insure a long lifetime keep the ON times low and the OFF times high for a given spark length Too low of OFF time may lead to rapid failure due to transistor overheating Too high of an ON time may lead to either catastrophic failure from overcurrent or slow degradation of the transistors due to long term abuse If you should ever damage the transistors replacement is straightforward and will cost around 10 Simply 1 Unscrew the heatsink from the transistors 2 Clip the leads on the transistors and remove the damaged ones 3 Desolder the individual leads that remain in the board Do not use too high of a iron temperature or overheat the board as it may damaged the traces 4 Install new transistors Then reinstall the heatsink taking care to not forget the silicone thermal pads 11 Conclusion And that s it folks We hope you enjoyed building our kit Be sure to check our website http www onetesla com
14. onsists of a toroidal transformer with the primary being the conductor in question This acts as a 1 N transformer and if there are I amps in the conductor the CT behaves as a NI amp current source Clamp In this context it refers to a waveform being truncated at a fixed upper and or lower bound Often used for protection purposes e g clamping the input to an IC to its maximum permitted voltages In our case however it is used to turn a very high amplitude sine wave into a pseudo square wave Flip Flop A type of logic circuit Flip flops take a DATA and CLOCK signal and output an OUTPUT signal The OUTPUT is updated only at the rising or falling edges of the CLOCK signal when it takes on the value specified by INPUT 15 D Copyright and Licensing The contents of this document of other documents included in this kit and of the schematics and PCB reference files found on our site and in the preceding Appendices are all licensed under the GNU Free Doc umentation License Full content s of this license can be found on the web but to put it briefly you are free to disseminate these files or derive work from them so long as your work is licensed under the GNU FDL After all every project can be improved and you might be able to improve ours We encourage you to spread the documentation and schematics it improves our business but more importantly might also inspire aspiring coilers everywhere to build a DRSSTC And the more co
15. rands of trifilar wire together tightly either by hand or with a drill Mark one end of the bundle with tape or a marker and then wind 15 turns of the wire tightly around the toroidal core Separate the three separate wires and twist the ends together Install the transformer in the board taking care to phase it properly as show in the following diagram Insert Image Here Figure 4 GDT Construction 6 4 Tesla Coil Secondary Carefully wind the included magnet wire on the included former to dimensions as show in the diagram below It is imperative that the turns to not overlap even one crossed turn will cause catastrophic failure of the coil If you purchased the Pro Ultra version of the kit you may skip this step as it comes with a pre wound secondary Insert Image Here Figure 5 Secondary Dimensions After winding the coil you may optionally varnish it with clear enamel or polyurethane This step is highly recommended as it increases the endurance of the secondary coil but is not necessary for operation 6 5 Toroidal topload Begin by inflating the included inner tube Inflate only until it is full enough to hold its shape overinflating may cause distortion or bulging in the tube In particular DO NOT inflate it to the pressures you would find in a tire as inner tubes are not designed for operation at full pressure outside of a tire Coat the inner tube and cardboard disk with aluminum tape Use the included spoon to smooth o
16. roidal sometimes spherical object connected to the secondary in a Tesla coil Its duties are twofold it increases the capacitance of the secondary thereby lowering the resonant frequency and it also prevents premature breakout from the Tesla coil by smoothing the electric field out MOSFET Metal Oxide Semiconductor Field Effect Transistor A voltage controlled transistor with an insulated gate terminal A power MOSFET loses energy proportional to I 2 Riso where is the current it is carrying and Ras on is the on state resistance of the transistor IGBT Insulated Gate Bipolar Transistor Another kind of transistor with an insulated gate and on state characteristics similar to those of a BJT IGBT s are purely a power device They dissipate as I log I where I is the forward current and are hence more efficient that MOSFETs at high current They are also far more friendly to high 300V and higher voltages where MOSFETs begin to have prohibitively high on state resistances The reason all DRSSTCs use IGBTs is because of the low losses at high currents not only do MOSFETs dissipate proportional to 1 their Ras on also increases with increasing current Switching Loss When a transistor transitions between ON and OFF it briefly behaves like a resistor The power dissipated during this resistive period is called the switching loss of the particular system Current Transformer Used for sensing current through a conductor It usually c
17. sla coil If built according to the instructions you should be getting at least 15 sparks with the ON time turned to 100 uS Optimizing oneTesla is fairly straightforward Add or remove primary turns as necessary in order to achieve maximum performance The optimal point is probably no more than half a turn away in either direction from the stock configuration Note that it is common for tuning parameters to change after mounting or moving the coil to a different location This is caused by the secondary capacitance values which are parastic capacitances to ground changing If you have an oscilloscope you can tune the coil with a scope as follows 1 Set up the primary and secondary exactly as they will be set up in final operational conditions This means that the secondary should be installed and grounded and the toroid should be installed Connect the positive lead of a signal generator to the toroid Set the vertical resolution of the oscil loscope to 50 mV div Connect the scope probe to a wire of around 30mm long you can leave the ground clip of the signal generator and oscilloscopes unconnected Set the signal generator to generate a sine wave of about 225 KHz The oscilloscope should display a sine wave Sweep the frequency of the signal generator from 190 KHz to 260 KHz The point at which the amplitude of the scope trace is maximum is the resonant frequency of the primary secondary setup 11 5 C
18. ut any wrinkles in the tape Using the included sandpaper sand the enamel off 2 of the loose wire on one end of the secondary Assemble the toroid and secondary as shown below Insert Image Here Figure 6 Toroid Assembly Purchasers of the Ultra version of the kit only you should have recieved a spun aluminum toroid in your kit You should have also recieved a plastic end cap and mounting hardware for this toroid Sand the enamel off the end of the winding as above and then assemble the secondary as shown in the following diagram Insert Image Here Figure 7 Pro Ultra Kit Only Toroid Assembly 7 Primary Coil Wind the primary coil using 12 AWG wire according to the following diagram Insert Image Here Figure 8 Primary Dimensions 8 Assembly and Troubleshooting Now comes the fun part The coil is nearly assembled but don t connect the primary coil or plug in the main power just yet 8 1 1 2 O 0 N Q Step 1 Verify Logic Functionality Plug the 19V wall adapter into the power jack on the board Plug the wall adapter in Verify that the both LED s are on If not confirm that they are installed with the correct polarity that they are properly soldered and that the power jack is properly soldered Connect the interrupter to the driver using the included fiber optic cable At this point if you have an oscilloscope verify that pin 3 on both gate drive IC s are low duty cycle square waves of a few hun
Download Pdf Manuals
Related Search