Electromagnetic Disk Launcher

Project Type: Propulsion and Levitation

Project Information

Project Description:

The task is to design, build and test a device that launches scrap aluminum hard-drive platters high in the air using pulsed magnetic fields.  Energy for the launch is stored in capacitors and released to a flat-wound coil using a solid-state switch.  When the switch is closed, thousands of amperes flow through the coil and produce a brief but intense magnetic field.  The pulsed field intercepts the disk resting on the coil and causes the disk to conduct an extremely high eddy current by transformer action (induction).  The currents in the coil and in the body of the disk produce magnetic fields that repel each other and launch the disk into the air at a high velocity.  The project also includes the design and construction of a seperate load coil that crushes soda cans with similar magnetic forces.

The process of inducing currents to flow in a conductor by time-varying magnetic fields is used to turn induction motors, propel magnetically levitated trains (linear induction motor), and heat cooking pans on an induction stove.

Level of Difficulty: Low


aluminum electrolytic capacitor, silicon controlled rectifier (SCR), diode, pulsed power, magnetic induction, coil gun, microwave oven transformer, pulse transformer, eddy current, Lenz’s Law, skin effect, equivalent series resistance, stray inductance, theta pinch, hoop stress


“Linear Motors,” by Chris Woodford, May 15, 2012, http://www.explainthatstuff.com/linearmotor.html

Team Roles

Electrical Engineer (2) – Electrical Engineers on the project are responsible for the design and construction of the power supply, capacitor bank, solid-state switching and safety systems that deliver a pulse of power to the load coils.  Achieving these responsibilities will require a thorough DC and pulsed analysis of the circuit using network theory and simulations.

Mechanical Engineer (2) – Mechanical Engineers on the project are responsible for the design and construction of the load assemblies that include a flat coil for launching hard-drive platters and a short coil for crushing soda cans.  Both assemblies must be designed to withstand the tremendous magnetic forces and be safe for public demonstrations.  Design responsibilities also include a low inductance power-coupling system between the coils and the capacitor bank.

Physicist (2) – Physicists on the project are responsible for understanding and optimizing the forces delivered to the hard-drive platters and soda cans by calculations and simulations.  Maintaining high-force coupling is the key to a successful system.  All other subsystem designs must cross-checked by the Physicists to assure the overall goal of high force is not degraded.

Computer Scientist (2) – Computer Scientists on the project are responsible for all controls and diagnostics on the project.  These include DC and pulsed measurements of voltage and current; manual and electronic trigger networks; and system interlocks to assure safe and sequential operation. Data and controls are computer based.

Designer (2) – Designers on the project have the difficult job of blending the design goals of the various teams into an device that can be manufactured, maintained, assembled quickly, transported by hand, and is safe to operate and demonstrate to crowds of people.  Designers validate system designs via CAD illustrations, supervise component manufacturing, and resolve operational problems that require modifications.

Journalist (1) – The Journalist documents the project’s progress on the website, communicates with the local media, and is responsible for a final report to the principal sponsors and Power Mountain Engineering.  The Journalist also works closely with the Multimedia Artist to provide video and graphic art displays for demonstrations that explain the project to the public.  The whole project is your project.

Multimedia Artist (1) – The Artist also documents the project’s progress on the website and works with the Journalist to maintain the project’s presence on social media.  Additionally, the Artist designs and organizes all public relations events to assure spectator safety and to enhance the community’s awareness of science and technology.  The whole project is your project.

Business Manager (1) – The Business Manager is responsible for reporting the project’s progress against a predetermined schedule, determines critical path items to completion, and tracks project spending to assure that costs remain within a fixed budget.  The Manager works with all team members to identify problems early and resolve them quickly.  The whole project is your project.

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