# Linear Generator

1. Apr 20, 2010

### Petrucci

Before building a linear generator I am trying to figure out how much energy it will produce over a given period of time, but I'm having trouble getting my head around it.

Firstly, assuming I can measure displacement (of the magnet) vs. time, specifications of the magnet, and the dimensions of the coil), can / how do I calculate rate of change of flux through the coil?

The big one: Can / How do you calculate total energy produced?

One last little querie: Is the total energy produced by moving a magnet a distance d in a coil dependent on the time it takes to do so? In other words will moving it d in 2 seconds produce more(or less) energy than moving it the same distance in 4 seconds?

Any guidance is appreciated!

2. Apr 20, 2010

### Petrucci

0 .. :(

3. Apr 21, 2010

### Antiphon

The energy it delivers will be V*I integrated over the time of the linear stroke. V will be the open circuit EMF which will be equal to the time derivative of the flux. So the faster the magnet moves, the higher the voltage. The current will depend on the load you connect to it. Maximum power transfer will occurr when the load has the same resistance as the generator's coils.

4. Apr 21, 2010

### pallidin

As an added suggestion, keep safety foremost in mind.
Both kinetic and electrical shielding.

5. Apr 21, 2010

### Petrucci

Thanks very much for that.

Alas, 1 little thing... (assuming you know the structure of the generator and can measure displacement vs. time of the magnet) Is there a way to figure out the time derivative of the flux theoretically? OR, do you have to directly measure voltage with respect to time and then figure it out?

Cheers.

6. Jun 3, 2010

Did you figure out the equation for the stroke displacement with the cycles per second for the V output?

I am still trying to figure this out but no one seems to know.

Anything would be appreciated.

7. Nov 22, 2010

### kurtdtn

I drew a graphic of a linear generator and put some questions on it. Does this represent the problem that you are discussing? I would like to build a model with some "Bucky Balls" (very cool toys). Here is the link to the image; http://gravitybuoyancy.com/lingen.jpg