Playing children spin the merry-go-round deck which is coupled through a spherical (1) bearing to a multi-stage
helical gearbox (2) turning backward as a speed increaser. These two mechanical devices are not new, but
computer based manufacturing and synthetic lubricants have pushed their combined energy transfer efficiency to
The high-speed output of the gearbox is coupled to a wind turbine generator (3). The generator has permanent
rare-earth magnets and special windings that convert over 70% of the mechanical energy to 3 phase AC electricity.
A buried conduit (4) routes the electrical wires to the power box (5) which contains a full-bridge rectifier, a solar
power controller and a large storage battery. The rectifier converts the 3 phase AC power to constant polarity DC
current. It doesn’t’ matter which way the merry-go-round turns the DC current is the same. The DC power from the
rectifier moves to a solar power controller. The solar power controller manages the incoming variable voltage power
to charge the storage battery efficiently and in a manner that prolongs the battery life by not allowing over charging
or damaging deep discharging.
A side benefit of the voltage regulation provided by the controller is that a DC line from a conventional solar panel
can be connected in parallel with DC from the rectifier to augment the total power supply. EPI adds a 60-watt solar
panel to the system, increasing total power by about 40%.
Finally, the power from the storage battery is used to recharge smart, LED lanterns (6). Smart because an
embedded computer chip manages charging and discharging the lithium ion battery pack ensuring long life for the
lantern. LED lights use less than 4 watts to provide the same light as a 40-watt incandescent bulb.
The lanterns are used at home by lantern groups of 3-6 children, and returned to school about once every two
weeks to be recharged. A responsible student is selected as the lantern group leader to manage the lantern for the