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OS:Milkovic-Berrett Secondary Oscillator Generator

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Prototype built by Brian Berrett, when optimized, is expected to result in a many-fold gain in output in the electrical induction on the secondary oscillations in the larger wheel, compared to the electrical input expended to keep the primary pendulum (oscillating wheel on the right) in fluctuation.
Prototype built by Brian Berrett, when optimized, is expected to result in a many-fold gain in output in the electrical induction on the secondary oscillations in the larger wheel, compared to the electrical input expended to keep the primary pendulum (oscillating wheel on the right) in fluctuation.

Brian Berrett of Lehi, Utah has built a two-bicycle-wheel device designed to use the patented two-stage mechanical oscillator principle set forth by Veljko Milkovic in order to produce electrical amplification.

It is presented here in its rudimentary beginnings, to spur research by others who can accelerate its development into something practical that could be easily built to produce useful free energy output.

While sophisticated commercial versions are likewise encouraged, the emphasis here should be on simplicity, both in materials and in construction, using off-the-shelf components easily obtainable anywhere in the world.


Open Source Project

On March 3, 2007, Berrett agreed to open source this project at PESWiki.

Inspiration: Veljko Milković

  • Milkovic Two-Stage Mechanical Oscillator - Serbian inventor, Veljko Milković, shows how leveraged secondary oscillations produce around twelve times more energy than the input energy supplied to the primary pendulum. Highest scientific rating of "original scientific work" granted the patented technology.

Latest Developments

March 18, 2007

Berrett Device Description

Motor Diagram -- Introduction

The following is a simple representation of the secondary oscillator amplification effect put forth by Veljko Milkovic.
Image:Milkovic-pendulum diagram by Berrett 500.gif

The input energy required to keep the pendulum swinging on the right, as measured by the fish scale, is at least ten times less than the output force generated on the secondary oscillator as measured by the bathroom scale.

Based on that concept, Brian Berrett came up with the following design.

Image:Milkovic-Berrett motor diagram 500.gif

Bicycle wheels are used because of their bearings to allow low-friction oscillations -- not continuous rotation.

The 12-inch wheel on the right is affixed by its axle to the perimeter of the 26-inch wheel. A counter-balance weight is affixed on the opposite side of the 26-inch wheel.

The spring helps keep the mechanism in proper alignment.

The 12-inch wheel on the right serves as the primary pendulum. Its oscillations are kept in motion by the drive coil.

As the primary pendulum oscillates back and forth, it creates a secondary up and down oscillation in the 26-inch wheel.

The magnets affixed around the perimeter of the 26-inch wheel induce electrical current in the coils as they pass back and forth by them.

Rudimentary Beginning

As presently configured, this system is not stable. The longest Berrett has been able to run his system has been about fifteen seconds. Obviously, the many variables need to be tweaked to come up with a formula that results in a stable, continuously running output.

The Challenge

This system produces very high torque at very low frequency -- the opposite of what is optimal for electrical generation.

Driver Circuit

Image:Driver circuit 600.gif

Circuit function description:
The magnetic reed switch is activated by a small magnet attached to the pendulum wheel. It is preferred that the magnetic reed switch is switched on and off as quickly as possible, when the large drive magnet and coil are aligned center to center.

The capacitor acts as a delay-off to keep the power MOSFET on for an adjustable period of time after the magnetic reed switch is off. This allows for a good magnetic push in the direction the pendulum is swinging. This delay is adjustable through the variable resistor, but the delay must be short enough to turn off before the pendulum changes direction, and moves back towards the drive coil.

The 1k resistor is merely a protection component to make sure there is not a short through the reed switch when the variable resistor is adjusted to minimum. It is important to stay within the absolute maximum ratings of the MOSFET.

You may need to adjust the values of the capacitor and resistors to achieve the proper timing.


  • Materials List - pending
    • Materials sourcing - pending
  • Instructions - pending
    • Assembly - pending
    • Operation - pending


Berrett is willing to provide the circuit board to people experimenting with this technology. More info and pricing available soon.

He used doorbell ringers for the coils.

Building and Design Notes

  • Lever and pendulum must vibrate at the same resonant frequency.
  • Lever frequency is adjusted by changing the lever weight and/or spring strength or tension.
  • Pendulum frequency is adjusted by swing length only.
  • Leverage distance (distance between wheel axles) is adjustable, and will change the rate of motion of the two wheels, but not the frequency.
  • More weight equals more power!
  • System must be tuned.
  • Drive coil can be one or two coils (push one direction or both) and requires electronic flip-flop circuit or logic frequency divider circuit (see following diagram). * 26 inch bike wheel axle is mounted to the upright backboard.
  • 12 inch bike wheel axle is attached to the rim of the 26 inch wheel.

Additional Photos

Image:Milkovic-Berrett motor front photo 500.jpg
Enlarged view of the system.

- - - -

Image:Milkovic-Berrett motor circuit photo 400.jpg
Close-up of circuit and one induction coil (doorbell ringer).

- - - -

Image:Milkovic-Berrett motor photo 350.gif
Black-and-white photo of system, from another angle.

- - - -


Mechanical Lever

The force measured on the bathroom scale from the secondary oscillations in the lever are more than ten times the force required to keep the primary pendulum in oscillation, as measured by the fish scale.


There is only a small electrical advantage with just six induction coils on the secondary oscillator wheel as presently configured. The input coil consumes 1 amp at twelve volts at approximately a 20% duty cycle which comes to around 2.4 Watts. The output is between 200 and 300 mAmps, at between 14 and 15 Volts, which comes to around 3.5 Watts AC (sine wave). These are very rough measurements and don't represent a full curve analysis of the input and output.


The mechanical results indicate that with the proper configuration, significant net electrical gain could be possible, providing enough energy to keep the system operational while producing excess electricity for practical use.

The challenge will be to devise a mechanism whereby the low-frequency, high torque output in the secondary oscillator can be converted efficiently into electricity. Usually, generators require high rpm at low torque -- the opposite as what is presented here.

If the secondary wheel is surrounded by induction coils, the electrical output would increase. However, it is not likely that this low-speed, high torque situation is preferable to other mechanisms for converting the mechanical force into electricity.

Proper engineering is likely to result in many different practical solutions.

Ideas for Improvement

  • Add a spring on the left side to balance the spring on the right, to help stabilize the apparatus. -- SilverThunder 15:33, 7 Mar 2007 (EST)


  • Use a ratcheting flywheel attached to a generator via a geared-up ratio.

Piezoelectric Micro Generators

Measurable inputs and outputs

We need a much more controlled and measurable input device. Poking it with fingers will not do. The forces of a finger on the pendulum and the resistance needs to be measured. Might I suggest a sensor on the pendulum and the beam if both are correct, in reach, a servo or magnet tugs the pendulum. Both the force of this ‘tug’, its frequency and the energy lost to friction at the point of contact need to be measurable. One option is to power the magnet from the devices power output but a chain of two or more capacitors would be needs to break the time effects and prevent adverse feed back. Precise measurements of all forces both inputs and out puts must be made. Guestimates are not good enough. Energy is time dependant a small slow push can have the same energy as a large but faster out put push. One Newton for 2 seconds can out put as 4 newtons in ½ a second. Wesleybruce march 19, 2007.

Full Rotation

  • Full rotation of the pendulum will eliminate the low frequency/ gravitational acceleration limitation issue while maintaining the same system effect. [Force vectors of pendulum swing from highest point equal those of rotation.] One could simply align the device horizontal so that a small motor may be mounted to drive an unbalanced rotor through full rotations allowing much higher frequency oscillations. One could also add more imbalanced rotors for balance, increased efficiency, to eliminate unnecessary vibration, or even to induce rotation of the main wheel instead of oscillations. -- User:Joshua Gulick (March 15, 2007)

Inventor Profiles

Inventor: Veljko Milković

See: Veljko Milković profile

Inventor: Brian Berrett

Brian Berrett is a small business entrepreneur and has been self employed since 1998. He started two businesses. One is an electric bicycle business based in Los Angeles, CA, and primarily sells conversion kits. The second is an electric vehicle conversion company in Utah that he is presently managing. See

Berrett graduated from Pasadena City College with degrees in Electro-optics and Physics. he has experience working for NASA with Jet Propulsion Laboratories in the Education Department, and has also worked in the electronics divisions of Hart Scientific and Micron, inc. as an Electronics Technician.

His main passion is real-world applications of common technology. He is presently living in Lehi, Utah, USA, with his wife, Christine and their four children.


The above design is described in chapter 9 of a new book by Brian Berrett titled "Energy Abundance Now: A Brief History of Man's Quest for Energy." See:


  • list here


See Discussion page


Brian Berrett


Veljko Milković

See Directory:Milkovic_Two-Stage_Mechanical_Oscillator#Contact

See also

- Other Open Source Projects
- Open Source News
- PESWiki main index
- PES Network Inc.

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