My name is Trevor Hughes and I am a student at Nampa High School located in Nampa, Idaho. My friend Mason Trowell and I are working with the high school science teachers to design and build a coil accelerator. A coil accelerator uses copper wire wrapped around a non-metallic tube and high voltage/current going through the coil to propel a metal object through the tube. We are using a 1.1” diameter aluminum pipe and some high…

…capacitance capacitors. The use of 10 gauge wire allows us to have low resistance and therefor lower voltage losses. We are making a 3 stage accelerator for our project and we will use about 100 feet to complete the number of wrappings needed to make the three coils.  We will post more details as the project progresses…

Update 9/26/2010

We are one step closer to completing the coil accelerator project, and more details are emerging on the construction.  Our original plan was to use six 10,000 μF capacitors (two per coil), but we could not find a sponsor willing to donate them.  So we decided to try to earn the money to purchase them which was taking some time to accumulate.  As we were earning the money, we were able to get an offer of a donation from Automation Direct of multiple capacitors of a somewhat smaller capacitance, but which would also work.

We also learned that we might be able to accurately time the firing of the pulses of the three coils  with a CLICK PLC (Programmable Logic Controller) from Automation Direct.  The PLC outputs would have to actuate separate solid state relays rated for high voltages and currents involved.

We plan on using a Chrony F-1 chronograph to precisely measure the velocity of the projectiles.

Initially, we will fire only the first coil and record the FPS to determine the exact time the projectile gets to the second coil and so on to set the exact timing of the coils.  Our Science teacher has insisted that we focus on the safety aspects of this project.  One precaution that we are planning to take involves using electrical lineman’s gloves and he told us we might be able to receive them as a donation from an electrical lineman’s college or even the local IBEW union.  We will be contacting them next.  If anybody has a pair (or two) of lineman’s gloves that they are willing to donate, please post a reply…  Thanks!

Update 11/16/10

Our project is coming along quite nicely. We have decided to abandon the idea of the PLC/Relay system and go for what are called SCR’s. SCR’s (or Silicon Controlled Rectifiers) are a semiconductor that act like a very high voltage/current switch. We plan on using 3 per trigger because of their limited power capacity. Another update to our project is that we will be upping the power eventually and use 10 capacitors per bank instead of 5. We were able to acquire a large 40 Watt solar panel donated by Aurora power and Design, along with two Trojan T-105 6v deep cycle batteries, and the 12v solar charge controller to charge them. We are looking to get a 1000 watt inverter and a 400vac step-up transformer to give us the voltage we need, but we may also consider a 800v system by wiring half of the capacitors in series.  If anyone has either lying around that they would be willing to donate, I would greatly appreciate your help.  Some more changes in the project include:

• 1/2 inch diameter pipe instead of a 1.1″ diameter pipe
• the pipe will be PVC instead of Aluminum
• Previously mentioned, we won’t be using a 12v-400v transformer
• A larger solar panel will charge a larger battery bank that powers the inverter, transformer, and any other electronics.
• A larger bank of capacitors will be used.
• Our accelerator will be cart mounted and not handheld.
• Previously mentioned, we won’t be using a PLC or relays but use SCR’s instead.

If you have any questions, feel free to comment and we’ll keep you posted on the progress.

12/17/2010

Our project is slowly moving forward and a few crucial parts are still missing. The most important part at this point would be the SCR’s. We recently contacted Industrial Semiconductor Inc. to see about getting 9 donated. He asked for more details on the project soon after we sent the first email, and he has not responded back since. The coil accelerator cannot function as a 3 stage system without them, otherwise, too much power will be lost.

Aurora Power & Design recently donated a 55 watt solar  panel and 10 A charge controller for our project to charge the batteries, which we have yet to find a donation for, and I went and picked it up. It will be very useful in the coil accelerator project for charging it in the field.

As a bonus of the project, we are looking at cooling the coils with LN2, or liquid nitrogen. Our science teachers told us if we provide the dewar, they’re provide the liquid nitrogen. So we need to find a donation of a 10 liter dewar and then that will cool the coils by a factor of 10, letting us squeeze all the power we can out of it. If anyone knows where we can obtain a 10 liter dewar, please write to us in the comments!

Here are the missing parts:

• 9 SCR’s
• 1000 watt inverter
• 400 vac step-up transformer
• 2 Trojan T-105 Batteries
• Triggering Mechanism for the SCR’s (PLC?)
• Wheeled cart
• containment chambers to house the liquid nitrogen
• 10 Liter dewar

If you have any tips, or donations please write in the comments!

Filed under: Projects