World Fastest Six Stage Coil Gun Yak Questions Answered

[@RaptorRotorHead]

I really get amazed at some people that go around and tell people that their calculations are all wrong and then they leave and they don't put up one calculation of proof.

[@BM_brb]

I'm very interested in this project. i want to build my self a coil riffle. yes im waiting for the schematic 😊

[@insanescience8106]

I thought it was 14 guage wire not 16 guage?

[@jvon3885]

Such is the internets and everyone's ability to hide behind anonymity......they will never truly feel humility, so they just go through life being ignorant and soon they become willfully ignorant....Stupid.

[@dutciucmihaidelian9258]

Did you use some senzor for the coils like others coil guns i see on youtube

[@RaptorRotorHead]

no I did not use any sensors for the coil it's based on inertial

[@RaptorRotorHead]

I will upload schematic of power supply when I'm finished with the portable project and video it.

[@ancelb9590]

Schematic?

[@lucaswybrandt7058]

I don’t understand how you time the different coils? Shouldn’t you time the coils so that it matches the increasing speed of the projectile instead of how long it takes to discharge the capacitors?

[@howtomakeacoilgunoffallout4096]

Oh si por supuesto... See also New Portable Super Coilgun: kzbin.info/www/bejne/qJTPfaaHbtOsm8k&feature=youtu.be kzbin.info/www/bejne/Y57NdaSmlNSKkM0

[@HellTriX]

Subsequent stages should be fired sooner and faster than previous stages to make up for the speed of the projectile. Does your micro-controller/programming account for this? Thanks.

[@RaptorRotorHead]

Yes it does.

[@HellTriX]

@@RaptorRotorHead 3 years later, TY ! :)

[@RaptorRotorHead]

@@HellTriX it does show the timing in the video so it's there you just got to watch the whole thing through

[@davadoff]

@@RaptorRotorHead I still don’t understand how you know when to fire the later stages. If ferrite accelerates slower (since it is less effective ammo), then later stages need to delay more before they fire. How do you account for this delayed timing? The projectile, either ferrite or steel, should be accelerating through the barrel. It’s speed shouldn’t be constant. Waiting 2ms per stage or whatever seems to me like the wrong way to do it. Edit: Right at the end of the video.. you adjust the ‘timing’ by using smaller and smaller capacitors?

[@RaptorRotorHead]

@@davadoff first do you have a chronograph you have to have that and you have to have an oscilloscope do you have those two pieces of equipment? The easiest is a trial and error approach basically you decide how long a projectile you're going to fire am I giving example that's 2 in long so I have to wind a coil that's 2 in long. Now we pick some capacitance and we connect that across the coil with the s c r we put the 2-in projectile part way into the coil like 1/4 of the way so that's a half inch in. Now we set up the chronograph at the muzzle of the coil and we charge up the capacitor and we fire the scr and we measure the speed in feet per second on the chronograph. If the speed of the projectile is 75 ft per second now with some simple math you can figure out how fast the projectile travels in 2 in. 1/75= how long it takes to travel one foot. 0.013333 milliseconds. Now how many 2 inches are there in a foot there are six right? 0.013333/6=.0022 milliseconds. This is the pulse width of your first coil. You adjust the capacitance up or down and you test and you find the fastest projectile speed and you make the calculation that's the pulse width of your first coil. Your second pulse width for the next coil stage, it's going to be less than 2.2 milliseconds because the projectile is already moving and not going from a dead stop. About 1.2 milliseconds for the second stage. Each stage the pulse width must be quicker or the projectile will slow down. So that's a shorter pulse width for every succeeding stage. You will discover that you get the most feet per second out of the very first stage and every succeeding stage after that you get less feet per second added on your total feet per second. It works by basic law of physics mass and inertia a certain amount of mass a certain amount of inertia and that takes a certain amount of time to move the projectile it's how they shoot down nuclear missiles. Now went to fire the coils that's done with an Arduino Nano so you have to write some software and you have to program this two milliseconds here 1.3 milliseconds there and that's how it knows how to fire the coils the physical thing is figured out all you got to do is figure out the software thing the math to it and it'll work perfect every time with the same size projectile which weighs about 14 Grams. Now this is where the oscilloscope comes in you use that to measure the pulse width at each coil when you achieve the highest speed so that you know where you're at at the second coil you're going to have less pulse width so you'll measure with the scope and make it a little less then you'll check out your speed you go for the fastest speed it's adjust the capacitance up or down to get the pulse with at the optimum speed.

[@RaptorRotorHead]

yes the first coil is fired at about 2.1 ms then the next coil is fired for about 1.3 milliseconds, yes the pulses get shorter faster it has to or it won't work correctly.

[@RaptorRotorHead]

2 reasons one is those caps can fit inside of 4 inch ABS tube, second when you put many small caps together you lower the ESR of the capacitor that's the equivalent series resistance the lower the resistance the more energy that can rush out of the capacitor into the coil. it increases efficiency increases power.

[@multimargejta123]

I made exactly the same setup, the problem is when I fire the first coil it somehow triggers the second one without arduino..is that some kind of back emf? npn transistors are driving the scr-s

[@RaptorRotorHead]

EMF exactly a lot of it I got around that problem. I used opto couples in between the scr I connected the opto couples to the arduino. I used suppression capacitor on the gates of the scr connected to the anode and a little bit of resistive Network.

[@multimargejta123]

@@RaptorRotorHead okay, thank you I will try that

[@chuckthebull]

There are these ballistic guys on line that high speed film projectiles to see how they perform in flight. They use all kinds of different shapes to see what consistently flies straight. At a close distance you might never see much of a deviation in flight characteristics and it seems yours are moving straight in that small distance. I would be curious to know how the screw tips perform in longer flight. and if some sort of rifling or spin could be put on it to stabilize them. They already seem to have quite a good shape for this. I have been doing a bit of experimenting with maximizing my coil timing to see when and how the timing can be improved as in as the projectile gains velocity would having the pules width also change or speed up that timing to each coil as in a ramp up to match the moving object. i'm going to try and use smaller bits and see what i get.

[@mhuppertz]

Would like the schematic... ;)

[@RaptorRotorHead]

Schematic is in the video

[@TheIAMINU]

If you aren't going to vary the timing based on the velocity of the projectile , you could progressivly widen the spacing of the coils down the length of the barrel to achieve a higher velocity..

[@RaptorRotorHead]

TheIAMINU timing is adjusted by an oscilloscope that is how it is done accurately there's no need to space the coils the part that just slows it down, and that was verified by the scope that's why the coils are where they're at.

[@dalenassar9152]

How high is the charging voltage from your power supply?? You are charging 43 capacitors in parallel, each being 3600uF, through a 50 Ohm resistor: That comes out to an RC time constant (63% charge time) of RC=50*0.1548=7.74 seconds. But you claim a charge time of 4 seconds. If you charge them for only 4RC (for a 95% charge=427v) THAT takes 31 seconds. So, I am a bit confused, UNLESS the charge voltage is significantly higher than 450v. THANKS AGAIN FOR THE VIDEO!!!

[@RaptorRotorHead]

500 vdc is the charge voltage, it's works better when I used 40 amp hour batteries, 5 amp hour was about 8 seconds. Input pulse current could be as much as 50 amp. Then it drops.

[@dalenassar9152]

@@RaptorRotorHead Your charge supply has an undesired current drop somewhere. With a main charge supply of 500VDC through 50 ohm, all you should need is to sustain 10A for the charging time of a (very) few seconds. To Charge the total capacitance of 200uF x 43 caps = 8600uF, which is an RC time constant of 0.43 seconds, Your charge time to 450V should be ( at 5RC for a charge of greater than 99%) about only 2.1 seconds: even less considering your power supply can put out a full 10A for 2 seconds. I have done the math. This should be absolutely NO problem for ANY of the batteries you mention. This leads to the obvious conclusion that the power supply can't supply 500v at 10A for 2 seconds. There is definitely a droop in voltage (500v) and/or current (10A) during this time. MATHEMATICALLY: At C=8600uF, R=50ohm, V=500v (charging voltage, v=450v (target voltage), then you should be able to charge the entire cap bank from 0v to 450v in ONE SECOND! (0.990 seconds to be exact!). The formula in this case is: t= -RC ln[1-(v/V)] I will bet either the 500v or the 10A is less during the charge time. You could measure it quite easily. I have been doing this type of calculation for over 35 years.

[@dalenassar9152]

Clay, At about 13:39 there is a good shot of six small power resistors that seem to be connected directly to the coils (I can't tell if there is something else,like a diode, in there with them. I was wondering what this was for.

[@RaptorRotorHead]

dale nassar in the beginning of the video that's explain but I can tell you what that's for that's to take the energy from the collapsing magnetic field on the coil and feed it back to the capacitors backwards reverse voltage this reduces the suck back in the coil tremendously and this is actually why I get so much speed Plus the Barrow is carbon fiber .032 wall thickness so the magnetic flux is really close to the projectile this increases the speed, also the projectile has hexagon-shaped so it has six rails riding on the inside of the for the least friction possible

[@RaptorRotorHead]

dale nassar 4:57 go to this Frame this is the schematic of the diode and the resistor across the coil that's what you're looking at, it's about 7.5 ohms

[@bikobii]

I like how you set up your capacitor bank

[@arrshithrg5359]

why didn't you put any ferromagnetic walls or discs in between the coils to increase the flux density and force of attraction

[@pavelperina7629]

I wonder how long does it take to discharge capacitor through the coil that tries to avoid fast changes of current. Also isn't it possible to use one capacitor bank and power coils in sequence? And is it possible to use one coil to power the next one somehow? And I would discard any timers and use optical gate to detect bullet between stages to fire up the next one.

[@dalenassar9152]

I think I am making a little headway by re-watching your videos on the coil firing timing. Can you please tell me exactly what triggers the pulse waveforms of the coils--I am a bit confused on the vertical line at start--unless you are it triggering it around 400VDC amplitude. Using the "LC" formula gives a period "T" of about 6ms, and a time constant of anout one ms. I can see this possibility in the waveforms. However, ignoring the self-inductance (300uH) of the coil and using only the 0.2 DC Ohm in the "RC" formula yields a time constant (L/C), of about 83ms (ignoring "L"). I am guessing this does not show up due to the type of triggering used.

[@davadoff]

I think he hardcodes the timing in the arduino code based on experimentation

[@TheRealBigSwede]

You haven't done anything more about the gun. I was so looking forwards to update and maybe even a more powerful gun!

[@RaptorRotorHead]

Real BigSwede no money to build anything.

[@userunfriendly9304]

I wonder what you could do with the latest capacitors

[@dalenassar9152]

Hello Clay, I was just looking at your SCR firing circuit starting at about 22:30 I was wondering why the SCR current does not automatically cut off, due to holding current minimum, when the current hits zero amps--before the reversal. Shouldn't the SCR cut off automatically here? Thanks again!

[@RaptorRotorHead]

The current reverses in the coil when the magnetic Flux collapse, when that finished then the scr shuts off. And the capacitors charges up backwards then the diodes discharge the reverse voltage in the capacitors. Noted by the voltage waveform on the scope going below the center line.

[@enriquephan7729]

So why not 0 ohms? Diode current? I have found some that can manage up to 3000A for 8ms(but expensive).

[@MyMikey88]

I think that you can use the reverse current produced by auto-induction to recharge the capacitors,you just need to modify some schematic and use your microcontroller to switch the coil from discharge to recovery mode.All you need is a fast trigger/switch controlled by the micro-computer,this way you can increase the overall efficiency

[@sporkeh90]

With recovery mode you mean linear mode? As in an active clamp? There are many stupid things in this design tho, like the coils.. Too thick wire, not enough turns

[@user-rs8zg8ey2b]

@@sporkeh90 Talk is cheap, prove it.

[@sacrifer7499]

May I ask why you used diodes and resistors parallel to the coils? The thyristors shut off when the current is zero so there won't be any damage through induction voltage anyway. I think the parallel resistor even lowers your speed because the coil is losing the remaining magnetic energy more slowly compared to just let it fully flow back into the capacitor. I also experimented a lot with coil guns so far and also tried different more or less complex circuits like using the stored energy of coil 1 to assist coil 2 but also tried your resistor + diode parallel thing and also diode + capacitor in parallel but I couldn't see any advantage. Actually I just let the capacitors freely recharge with negative voltage and discharge them over 2 small coils with a few windings at the end of my 6 stage coil gun (so its somehow a 8 stage gun) to gain additional 7 m/s plus the capacitors are recharged with about +50V at the end by these last 2 coils. My coil gun is currently accelerating a 28 grams projectile to 95 m/s but Im still using single thyristors and big capacitors with screwing connectors which is really bad. Are you still working on your gun?

[@RaptorRotorHead]

You did not absorb any of the information in the video so all I can suggest is that you watch it again, the back EMF from the coils is conducted through the diode and a resistor in series not parallel that feeds back into the capacitor bank and charges the capacitor Bank up backwards you would think that it would be some damage to the capacitors but that only lasts for instant of time and then capacitors are discharged by the second diode and resistor in series in another part of the circuit which is shown in the schematic of the video and explained.

[@sacrifer7499]

@@RaptorRotorHead What I basically mean is that your circuit would also work without the resistor and diode (in series) parallel to the coil. I couldn't recognize any change when using it on my gun except capacitors being negatively charged a little less (like -200V instead of -260V) because at the moment the Voltage (at the coil) drops below ~ -0.5 V, the current generated by the coil will split and feed the parallel resistor+diode and the capacitor simultaneously.

[@RaptorRotorHead]

@@sacrifer7499 yeah it would work without it but at a loss of power. What are you using to measure speed? I am using a scope. The diode and resistor control the suckback on the projectile and the reverse voltage, mine was 200 volts. My coils were close to 300 turns. Without a resistor in series with the diode, the diode 20amp would explode. Unless there is a scope or chronograph to measure speed there is no way to know if the experiment is going faster or slower. What you see in the video is everything that is needed to get the maximum speed and control voltage spikes so as not to have too much EMP to confuse the computer system that fires the coils.

[@sacrifer7499]

@@RaptorRotorHead My measurement system is like yours but instead of a scope iam using the controller to measure the timing which also calculates the speed and displays it on a little oled display. Funfact: A Diode once exploded and also my Thyristor was destroyed because of that. The resistance was either to low or the Diode wasnt able to hold back the 1kV and simply bypassed the coil and thus shortcut my whole circuit. However, I measured no change in speed when placing a Resistor + Diode parallel to the coil (also changed the trigger timings). I tried several different Resistors and once I got +1 m/s but that wasnt repeatable so I think it was just a little error due to a slightly different starting position of the projectile. Maybe I'll give it another try soon with different capacities. I will also upload a video of my gun demonstration soon but actually you can only find one of my first coil gun which was a primitive brush commutated coil gun :) My current gun is far from mobile use with its weight. Im using 16 350V 3300uF capacitors each one 460 grams heavy. They are easy to connect and cost me nothing because we have dozens of them rotting unused in the company I'm working in. Next step would be ordering about 60 x 350V 1000uF capacitors with a weight of about 70 grams each but thats so expensive.

[@CA18DETHK]

If you're not using a physical trigger to sequence the coils, is it necessary to compress the timing taking into consideration the acceleration of the projectile? i.e. the projectile is moving faster and faster in the fields and thus the triggering time and pulse duration should be correspondingly reduced in successive coils or else the field could be acting against the projectile approaching the end of the array. Could that have acted against the overall efficiency when you use a constant timing sequence?

[@RaptorRotorHead]

CA18DETHK you are correct sir you are paying close attention I have to applaud you that is true the pulse duration in each successive coil has to be less because the projectile is moving faster and if the resulting pulse is not reduced it will suck the projectile back into the coil and reduce the speed.

[@CA18DETHK]

Thank you for the kind reply. Didn't notice that this issue had been brought up by Trix Kemuel before. I have a rudimentary rudimentary design to take care of this, by using a pair of thin wire to complete a triggering circuit using the projectile itself. The placement of the wire should be ahead of each set of coil so that the coil is energized before the projectile enters the coil and cut off before the projectile reaches the coil centre. A simple adjustable delay can be incorporated in the trigger to fine tune the timing for maximum effect. This will also take care of the pulse duration automatically. You're probably in a better position to consider whether this will work. By the way, have you ever tried firing a magnet to compare result? Thank you.

[@RaptorRotorHead]

CA18DETHK I did not try a magnet I was thinking about it to see what would happen but I could not find nothing that was matching in inside wall of the tube, simply using an adreno computer to control the firing sequence is like a cur down to three microseconds so every time it fires is the exact same power every time

[@enriquephan7729]

But the coil and resistor are in parallel, how is it possible they have different voltages? Sorry for the maybe stupid question but I dont get it.

[@benthere8051]

Would a projectile of less mass accelerate faster? Do you have to tune the design for the projectile? If your projectile was a needle, how would that affect the design?

[@RaptorRotorHead]

If the projectile was a needle you basically wouldn't be able to wind a coil around a tube because it's so small you will not be able to put very fat wire you limit your current you limit your power, yeah you have to tune the design to match the projectile that means how many coils of wire to thickness of wire how long do coils are how long a projectile is

[@benthere8051]

​@@RaptorRotorHead - Thank you for answering. I understand that problem and have addressed it already by devising a way to wind the coil in single layers without reversing the direction of winding. It's assembled like a stack of pancakes. And the needle is not a sewing needle but a carpet needle, dozens of times larger. Same question applies dear sir.

[@user-rs8zg8ey2b]

Why would you need to remove the rise time delay for the sensors? Both sensors have the same delay. Lower the pull up to the limit of the sensor, at least drop to 1K.

[@somneleda]

kinda wondering if you tried to fire a neodynium cylinder magnet also wonder if that ferrite was too light so passed the center of the coil and rebounded before the coil shut down.

[@enriquephan7729]

I think, correct me if im wrong; letting that reverse voltage will make the inductor current drop down much faster, yes?

[@RaptorRotorHead]

maybe in a week what to do with 30 and 50 foot long shot test I it's going to become an electromagnetic crossbow

[@luismorales8085]

Hello sir, it's me again. Is it okay if I use an aluminum tube as a barrel for my coil gun? Or will it have interference with the magnetic fields making the projectile go slower?

[@RaptorRotorHead]

No don't use aluminum tube that will ruin it, user carbon fiber tube the hobby store.

[@luismorales8085]

Thank you so much!

[@enriquephan7729]

I still dont get why the series resistance with the diode is that small. Why would the voltage increase if the resistance is bigger?

[@ryccoh]

V=IR

[@RaptorRotorHead]

I wasn't sure if I could fit the wires on the transformer voltage doubler allows me to use one half the amount of turns. also I need two spools to wind it and I only have one.

[@johnconrad5487]

I just came across ur video. great shot!!! very good design. Thanks for sharing. I noticed that u had the caps in a circle as if initially intending to install them around the coil which would be much more efficient. short wires to the coils. why did u not do that? did they not fit around the coils?

[@rev.kenshostad2888]

What would be the smallest projectile you can use, and with the smaller size would this increase the effective distance? What is the current effective distance? Could you make a system that would be comparable to a bullet?

[@RaptorRotorHead]

Size would be what your hands could hold and wind a coil. Compared to bullet no. Bow and arrow yes or crossbow you can match those speeds. No increase in range with small size.

[@costhee242]

@@RaptorRotorHead Try a toroid coil instead of solenoids. The former are 'magnetics' while the latter are 'RF' addressing only light and electrically charged 'projectiles' such as particles or small molecules, tuned to transfer energy for kinetics.

[@arrshithrg5359]

did use a op amp comparator to convert the irregular triangular pulse into square wave .or did you just put a voltage drop resistor. in your chronograph

[@RaptorRotorHead]

Vasudev Mr kzbin.info/www/bejne/f2WZcoSop5x3d9E watch this

[@arrshithrg5359]

Clay Reid mass driver has a brighter future . and I am seeing adds before your videos

[@RaptorRotorHead]

Vasudev Mr I like this for a weapon much simpler to construct only need a single stage the magnetic pulse if you put an iron Rod around the coil it carries the magnetic pulse further and it pushes the aluminum projectile harder and faster

[@RaptorRotorHead]

Vasudev Mr I did not get that link from you to watch email it to me

[@eam81969]

Why does the capacitance go down as the projectile increases in speed? Wouldn't it be the opposite?

[@RaptorRotorHead]

Capacitance has to decrease with increasing speed of projectile. If pulse to long projectile will be sucked back into coil. Timing is everything.

[@eam81969]

@@RaptorRotorHeadVery cool. Thank you.

[@alexanderpinkerton3452]

@@RaptorRotorHead Is it possible to use the SCR or a IGBT or something to cut the current from the capacitor to limit the pulse width without needing to reduce the capacitance of the stage? Is this possible or will this make something explode? :P

[@alexanderpinkerton3452]

Another question to drive it into my head, your circuit uses the nano to time the ON time for each stage but the OFF time is controlled by the capacitance? Is this correct?

[@enriquephan7729]

So what am I looking for so? Low resistance?

[@SunTzuLao]

Is there a reason that one large coil can't replace a multi stage system? Wondering about accelerating the velocity of a preaccelerated projectile. Thinking conventional propellant.

[@RaptorRotorHead]

The projectile cannot gain enough speed with one coil you might make 100 ft per second, with two coils you could make 147 feet per second with three coils you make 180 ft per second so as you can see I've already tested this out each successive coil get you less and less speed. Maybe you could use one coil if you use 10,000 volts, and sling a massive projectile, but then we're beyond the voltage rating of this circuit.

[@SunTzuLao]

@@RaptorRotorHead Ahh, yes I'll definitely be using a different circuit. My friend has much more knowledge on this end. Projectile will be quite large by comparison, I'm thinking 12mm, about an inch and a half long tool Steel cylinder with a carbide core. Construction of such a prototype is legal in my area as long as I don't exceed a given diameter of projectile where it becomes a "destructive device" as per US federal laws. I'd like to achieve 6000fps, which is crazy, but shoot for the moon right 😂 science. Not dismissing the multi stage coil though, just wondering about the reason you used it.

[@SunTzuLao]

@@RaptorRotorHead obviously I have a serious amount of math to do, I'm a prototype machinist with access to machines and exotic materials, and I have friends who are adept at welding and circuit design, electric motor building soldering etc.

[@RaptorRotorHead]

@@SunTzuLao if you expect 6000 feet per second you better use rail gun technology to get that.

[@SunTzuLao]

@@RaptorRotorHead yeah it's so much more complex though, and fragile. Was hoping I might be able to overcome some of the shortcomings of coil gun theory like magnetic saturation by using it for a secondary acceleration mechanism.

[@arrshithrg5359]

why should the capacitance decrease serialy as number of stages increases

[@multimargejta123]

I am interested in arduino code that you use for firing each coil, also want to know the capacity of capacitors for each coil. How can I contact you? sorry for bad english

[@arrshithrg5359]

my Arduino is facing a huge electrical disturbance form my zvs charger , especially while I flip the switch off . ma Arduino is just triggering the Coils even without a trigger pulse. and I found out that was because of common ground ( common power supply) .CAN you please suggest me some solution

[@RaptorRotorHead]

I used carbon fiber tube .032 wall thickness to wind the coils on.

[@richardbowden4421]

+Clay Reid Thanks, great job on this project.

[@enriquephan7729]

I get a massive reverse voltage: Current through the inductor would be 2250 amps, now the parallel resitance would have a voltage of V=2250*7.5=16875V, What am I doing wrong?

[@arrshithrg5359]

what is cryo freeze the coils, actually i did not get your answer .i wanted an scr which could handle 5k-6k amps of current pulse

[@Azagro]

Oh right, so the relay I see it to tackle the inrush current going to those capacitors? Meaning the capacitors for the voltage multiplier, not the main cap bank.

[@evanstewart2432]

Love it.Wonder if the Eddy currents are effecting it.Something to think about .Metal tubes attract Eddy currents.Coils themselves will attract Eddy currents .Always openvto suggestions on getting rid of Eddy currents. Will increase efficiency drastically

[@RaptorRotorHead]

It doesn't have a metal tube it's a carbon-fiber tube.

[@arrshithrg5359]

did you come across any miss triggering of the coils , while switching off the charging process ,or while charging process itself

[@y9844]

Which one is more efficient coil gun or rail gun?

[@vincentchung2316]

Can u combine coil and rail gun that make more power by using discharge inside the barrel to the coil like 1st normal coil gun 2sc is discharge 4 the 2sc coil useing the armo , that make the armo magnetic force to the 2sc coil . I hope it work and that what i think.

[@RaptorRotorHead]

Why don't you build it for me

[@RaptorRotorHead]

okay tomorrow I will have video winding the coil. were you able to measure the speed of the brass tube

[@arrshithrg5359]

for a brass tube of od 11mm and id of 10mm seed was was less than 5 m /sec , i am using low carbon mild steel rod as a stator

[@RaptorRotorHead]

Vasudev Mr kzbin.info/www/bejne/f3qbop2Mg9mJf7s watch this video

[@arrshithrg5359]

yeah ve i have the same kind of setup , but projectile is bit lengthy ,it about 30mm in length only getting 5m/s

[@arrshithrg5359]

how to properly connect igbts in parallel , is just like connecting collector to collector , emitter to emitter ??

[@RaptorRotorHead]

Vasudev Mr yes. that is correct. put gate resistor on each gate.

[@dalenassar9152]

Clay, I was talking to a coilgun designer that uses high-power drive SCR's (similar to your situation) and he claims to have proved that it adds velocity to use tight flat heat sinks pressing on BOTH sides of the SCR to eliminate "hot spots" during the brief firing duration of the SCR. What do you think??

[@RaptorRotorHead]

He's high on drugs, I use 10 scrs in parallel, for each coil, good for 5000 amps pulse duration is 2 mil seconds, there is no heat build up, the heat is in the first coil. That's the longest pulse. After 20 Shots That COIL Can Get hot.

[@gexometilentriperoxiddiamin]

Good gun) but i stiil didnt understand what speed the projectile reaches?

[@RaptorRotorHead]

About 260 feet per second.

[@gexometilentriperoxiddiamin]

@@RaptorRotorHead Do you think it is possible to reach a speed of 100 m / s? 260fps≈79m/s

[@sacrifer7499]

@@gexometilentriperoxiddiamin well that only depends on the number of coils and the voltage you use. It's helpful to increase the voltage in 330 volt steps for every 2 or 3 coils for example. So coils 1 and 2 @ 330V, coils 3 and 4 @660 V and coils 5 and 6 @ 990V and so on. This way you achieve a linear increase in speed per coil.

[@UsmanShery]

so i was wondering if you can mix up coil-gun and a rail-gun. railgun seems better in delivering power. people have been trying to make one but they just destroy gun itself and its not really useful, what if it can be improved with little back push and railgun action?

[@RaptorRotorHead]

Usman Shery it would be a waste of money time and efficiency to try to mix a rail gun with a coil gun. Well the railguns have the greater efficiency and the push on the projectile there rails wear out fast even the military has to replace them every so many shots.

[@RaptorRotorHead]

Remember there is no inductance in a saturated coil. That's only the DCR is the determining factor for the current flow. Saturation is reached quickly as shown on the scope with the rise of the waveform. Thus my megawatt calculation in the beginning is a very good starting place to figure out how much power is being pulsed through that coil

[@jamesmorton7881]

A string of CMOS mono-stable pulse generators would work really well for timing a string of coils.

[@oshinwane6902]

☝🤓 of course

[@jvon3885]

I'm working on projects from scavenging parts, the only thing I'm using out the box is my arduino.

[@howtomakeacoilgunoffallout4096]

Oh si por supuesto... See also New Portable Super Coilgun: kzbin.info/www/bejne/qJTPfaaHbtOsm8k&feature=youtu.be kzbin.info/www/bejne/Y57NdaSmlNSKkM0

[@RonioFOX]

you can do a test in a ballistic gel skelleton or a long range test, will be cool

[@RaptorRotorHead]

RonioFOX hi, check this out. long range test. kzbin.info/www/bejne/epvSinuCrsplppY

[@RonioFOX]

thanks

[@specterufo4009]

Where are the plans for the power supply?

[@RaptorRotorHead]

They're in my video list it would be switching power supply part 1 part 2 part 3 but mainly part one and part two

[@specterufo4009]

Will check it out thanks for the cool video!

[@kikeekik]

hey, you will upload some more info about the half bridge? I'm so interested

[@mauritsschoonderwaldt676]

why do you reduce the amount of capacitors on the further coils?

[@RaptorRotorHead]

yes I was simplifying on that but also if you look at the scope waveform you can see the effect of the inductance it's only about a hundred microseconds of time you can see the voltage hang for about a hundred microseconds then it starts to fall at that point right there the coil is saturated and the inductance is gone all that's left is the DCR to discharge the capacitor.

[@user-rs8zg8ey2b]

I will have to disagree with that statement. You need a current probe or current transformer. You need to zoom in the the signals, you are losing so much resolution with the scales (voltage and time) you are using.

[@arrshithrg5359]

why only 7.5ohm resistor with that diode .why not more than 7.5ohm and what will happen if it is more

[@brandonclark7333]

Any reason you chose to use so many small caps over a few larger capacitance once? Other than they look really cool?

[@czephei87]

Does run the SCR Array simultaneously ? Cant belive that :x. Wouldn't it make more sense to use Line Thyristors instaed ?

[@sacrifer7499]

thyristors behave like a normal resistor once they start to conduct the current with a pretty much linear U/I ratio. So running 2000 Ampere through them produces a Voltage drop at the thyristors of 20 V for example. So parallel makes sense to reduce their resistance. Also thyristors react a lot faster to gate current than the main current would be able rise since there is a coil delaying the current, so parallel thyristors arent problematic in any way as long the gate power supply can deliver these 10 x 0,2 Ampere for a short duration.

[@czephei87]

@G E T R E K T 905 kennen wir uns ?

[@czephei87]

@G E T R E K T 905 achso ok. Ja aber ich bin da wie man merkt nicht mehr aktiv am Videos machen.

[@czephei87]

@G E T R E K T 905 ja ich habe Videos entfernt. Es kann gut sein das dieses auch aussortiert wurde. Im Laufe der Zeit lernt man vieles dazu und in manch einem Video von mir habe ich schlichtweg halbwissen kund getan.

[@arrshithrg5359]

to find the lc time constant will you consider the length of full pulse including negative pulse ??

[@arrshithrg5359]

if I don't put 7.5 ohm resistor in series to that protection diode,will output power decrease??

[@arrshithrg5359]

when i connect my oscilloscope across the coils ,even though i have fed the delay time to my computer all the coils will trigger at once .but when i remove the probes from my coils .the coils will trigger flawlessly with delay time. completely weird .

[@arrshithrg5359]

why do we need a air gap in flyback transformer , like in zvs converter.

[@doubleooh7337]

If you have just one coil whats the max charge you dump into it? and how much velocity can you get?

[@RaptorRotorHead]

About 80 feet per second. Each additional coil add less and less.

[@doubleooh7337]

@@RaptorRotorHead i wish therecwas a easy way to make multicoil setup i cant do all thid stuff, but ready to try a single coil again

[@arrshithrg5359]

what is that Hamming sound in your place , I hear that sound In all the other videos also

[@enriquephan7729]

Which is 450 volts, isn't it? If not, where do you get that voltage? And thank you.

[@RaptorRotorHead]

Audrino microcontroller you can get them on ebay for as cheap as a 1.99 each. I wrote a program to put into the audrino that fires the coils at basically the same time constant as the LC time constant plus a teeny bit more I mentioned it in the video.

[@MissAlicePaige]

thanks for the great video. I'm hoping to start making an at least 24 inch barrel, as a sniper style rifle.

[@arrshithrg5359]

while measuring the speed you will subtract rise time but what about fall time should we subtract it too ?

[@RaptorRotorHead]

Vasudev Mr yes

[@arrshithrg5359]

Clay Reid I subtracted both rise time and fall time from the pulse and now I get 81m/s reading before I got 65 m/s without subtracting RT and ft .

[@arrshithrg5359]

is the 6 different stages triggered by 6 diffrent power sources ? , I mean gate voltage for scr

[@arrshithrg5359]

may be i think increasing the voltage will help a lot . i will just try connecting cap in series to power the gun

[@arrshithrg5359]

I observe that you have connected many small valued capacitor in parallel , why didn't you choose a single big enough capacitor to make it compact ??

[@RaptorRotorHead]

Vasudev Mr it has six stages it has six independent capacitors, the coil and the capacitors have to be tuned to each other you just can't put one big arbitrary capacitor you have to have a certain amount of pulse width not too much and not too little. more capacitors in parallel lowers the ESR of the capacitors that makes four more efficient coilgun

[@arrshithrg5359]

Clay Reid I asked this question because when I replaced a capacitor bank of same capacitance but different capacitor type the performed was bad. at first I had used costly capacitors and when I replace them with small sized once ,not good

[@RaptorRotorHead]

Vasudev Mr you have to use switching capacitors. they have low ESR, when you combine many in parallel you have super low ESR. it's easer to adjust the pulse width in small increments, if a single capacitor is to be used it should be a photo flash capacitor.

[@RaptorRotorHead]

yes that is Arduino powered by the same power supply that powers all the other circuits especially in my later model design

[@arrshithrg5359]

Clay Reid does the optocouplers directly drive the scr bank or do you have any transistors hooked up to optocouplers to drive the gate of scr

[@arrshithrg5359]

do you think your scr bank can take a direct short circuit pulse ??.

[@arrshithrg5359]

your cro as a chronograph seems interesting . even I have 30mhz dso ,but I don't know how to calibrate it to work as a chronograph. can teach me

[@RaptorRotorHead]

yeah the 50 ohm resistor is connected to the output of the power supply. the core is a PQ 43535.

[@arrshithrg5359]

are this languages of your days , and where did you learn it

[@RaptorRotorHead]

measured with that oscilloscope that you got, put the scope across the coil and measure the width of the pulse that's the time delay for the next coil to fire when the capacitor has emptied the next stage should fire

[@bgoggin88]

What would make it more efficient?

[@arrshithrg5359]

will you use the same scr which you have used here in your portable coil gun

[@clementdeogratius2753]

how did you make the cap bank charger

[@arrshithrg5359]

please tell me the part number of that 63amps diode

[@ChineloBelico]

Good day! :) What kind of tyristor/SCR/TRIAC did you used? (my project:single long coil -> 12000uf 350v) :)

[@arrshithrg5359]

what is the inductenc of your coil

[@davidprothro6763]

Is there a site where I can get schematics on this project?

[@RaptorRotorHead]

Watch the video the schematics in the video

[@davidprothro6763]

@@RaptorRotorHead , Thanks for the response, all the pieces of your project look to be very well designed. I'll watch it again.

[@Azagro]

Oh right, correct me if I am wrong, but the diodes on the capacitor banks are part of the voltage doubler or are you using the 3.3uF capacitors for that?

[@RaptorRotorHead]

it's a straight optocoupler but it's made to drive a IGBT so it works great on an scr.

[@arrshithrg5359]

Clay Reid which optocoupler is that ,can you tell the part number

[@RaptorRotorHead]

no the in rush is controlled by the 50 Ohm resistor the relay is the arming trigger for the computer

[@arrshithrg5359]

will the last Coil acelarate the projectile as same as first Coil ??

[@arrshithrg5359]

hey why can't we go for more voltage than 450 . i think the velocity of the projectile would increase even though the efficiency remains the same .

[@RaptorRotorHead]

Vasudev Mr that us true

[@ericksototalavera8161]

I liked it a lot, could you send me the scheme or diagram?

[@RaptorRotorHead]

I get constant speed the coils are fired at the same time sequence the voltage is exactly the same applied to the coils.

[@azathell]

So, may be i'm wrong, but when u accel from 0 to whatever in the first coil, u need to fire second, then it accelerates farther, then third coild needs to be fired faster to keep accelerating. I.e. First to second coil, 2 ms, but second to third 1.5 ms and so on so acceleration is constant and speed increases. If u keep firing them at 2ms u get constant speed and all 5 phases are not doing anything but wasting energy.

[@arrshithrg5359]

is that Arduino Nano powered by a same power supply you use for other circuits

[@Stephen-dg9de]

Hi could I get the schematics of your power supply?

[@RaptorRotorHead]

You have to look through my videos it's in there switching power supply 1 2 and 3