# Electromagnetic mass acceleration

some of you may have heard of a guass gun, coil gun, or em mass accelerator. if not google has you covered. I am designing a system which will utilize 4 or 5 electrolytic capacitors rated for 400v per cap, a dual stage coil with ir photo gates, and some other things.

The principle is that a high voltage is discharged into a coil of copper wire (solenoid) which creates a strong magnetic field inside the coil. This in turn can launch a projectile sitting inside this coil.

The major problem with these devices is overal efficiency, 8% is the most ive ever heard of. I will be using an IGBT switch, which is the most efficient means of pulsing the energy from the capacitors.

I am also shielding the coil with a silencer looking tube of iron.

Does anyone else know of a way to further the efficiency in such a scenario

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yep, FBI will be very keen to be informed about it ;)

pervect
Staff Emeritus
oldunion said:
some of you may have heard of a guass gun, coil gun, or em mass accelerator. if not google has you covered. I am designing a system which will utilize 4 or 5 electrolytic capacitors rated for 400v per cap, a dual stage coil with ir photo gates, and some other things.

The principle is that a high voltage is discharged into a coil of copper wire (solenoid) which creates a strong magnetic field inside the coil. This in turn can launch a projectile sitting inside this coil.

The major problem with these devices is overal efficiency, 8% is the most ive ever heard of. I will be using an IGBT switch, which is the most efficient means of pulsing the energy from the capacitors.

I am also shielding the coil with a silencer looking tube of iron.

Does anyone else know of a way to further the efficiency in such a scenario

http://www.oz.net/~coilgun/mark2/home.htm [Broken]

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pervect said:

http://www.oz.net/~coilgun/mark2/home.htm [Broken]
well the fbi can come kick in my door if they want, but considering how the local sports authority is selling bb guns at higher velocity than what i could make, they have better things to do.

I have already read half of the oznet. im more or less into theory now, and im nearly to the point of being able to pose an educated question to my physics professor.

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Your implication is that the resistance of the switch device is the culprit. If so, replace the semiconductor with a mechanical knife switch. Not fancy, byt effectively 'no' resistance.
Your problem may be the resistance of the capacitors.
Look for low ESR (Equivalent series resistance) capacitors.
Try aluminum electrolytic capacitors.

joe tomei said:
Your implication is that the resistance of the switch device is the culprit. If so, replace the semiconductor with a mechanical knife switch. Not fancy, byt effectively 'no' resistance.
Your problem may be the resistance of the capacitors.
Look for low ESR (Equivalent series resistance) capacitors.
Try aluminum electrolytic capacitors.
the internal gate bipolar transistor (igbt) is the most efficient switch they have for this application. Electrolytic capacitors will be used. i dont imply to know what the cause for poor efficiency is, but since youve sprung it on me, i would say that most efficiency is lost due to the air gap between the projectile and the external iron shield (which covers the coil) at the muzzle. So this would indicate that i believe the primary loss of efficiency has to do with overall reluctance of the em field.