Funky Axial Power Generation

[mgopalan]

Wondering what if any work has been done in building practical axially moving magnet power generators with real power ouputs.

I have an application where I have a lots of random axial vibration available (think of a giant hammerdrill) and I wanted to scavenge power out of the environment.Imagine a souped up kinetic flashlight. I know it can be done if I need only a few milliwats of power, but I need about 50 Watts! Ideally at 15-25VDC out.

My intuition says that I might try something very simple like a magnet moving axially inside a coil of wire or a variant thereof to generate the power just like the kinetic flashlight, maybe a stack of them? I dont think I want to try to convert the random axial vibration and try and rotate a dc motor shaft which would take my problem from one in magnetics and motor design to one in mechanical widgetry.

How could I go about this? My rough numbers says that I can get about a 0.25"-0.50" of axial motion of a magnet at 5 to 10 Hz for a 0.750" Diameterx 1.0" Long SmCo Magnet. If I stacked a bunch of these and had say 12 or 15 coils, would I even come close to getting the 50 watts or so I need?
Any and all advice will be appreciated.
MG

 

[mc5w]

Essentially what you are trying to build is something equivalent to a linear induction motor but with permanent magnets and reciprocation over a short distance. The biggest challenge is designing steel laminations that work right and are manufacturable.

Trying to harness that vibration of a hammerdrill is just going to give you a perpetual motion machine. Will not work.

Mike Cole

 

[jraef]

I for one did not interpret this as a perpetual motion scheme, but as an auxiliary power generation taking advantage of existing motion as the prime mover.

mgopalan, the problem here might be similar however. If you are able to solve the conversion problem, the raw power needed to generate 50W will in effect represent slightly more than a 50W increase in the energy used to create your motion in the first place, so your net gain will probably not be worth it compared to just plugging in a 50W power supply.

HOWEVER, if you are in a situation where you need some electrical power, let's say for instrumentation, in an area where only mechanical power is available to you, you may be on to something. I'm no help on the magnetics though, sorry.

"Venditori de oleum-vipera non vigere excordis populi"

 

[tinfoil]

Have you considered the electrical possibilities of piezoelectricity?

These guys found a way to power small electronic devices by scavenging energy from people walking by embedding peizoelectric transducers in show soles! :

http://www.computer.org/micro/homepage/may_june/shenck/

 

[tinfoil]

Oops
That should read ....shoe soles

 

[jraef]

That takes the prize for the coolest thing I have seen all year! Imagine, .8 watt per person times 6 billion people = 4.8 gigawatts of power available from sneaker power! Nike should reguister as a Power Utility.

Who says there is an energy crisis.

 

[UKpete]

If you don't want to go down the shoe route, there is (seriously) an application with a linear generator about to hit the market:

http://www.microgen.com/main2.swf

Basically it's driven by a Stirling engine for recovering electrical power from a domestic boiler flue. They use a moving magnet inside a stationary winding.

 

[jraef]

Great news. I love technology that reuses waste energy. It is a shame much of it goes up flues and into the atmosphere without being utilized. I can't wait to see it adapted for use in the US. seems like a natural for a lot of areas, especially appartment or condominium complexes with large common water heater systems.

"Venditori de oleum-vipera non vigere excordis populi"