Pedal powered devices by Hiren Jayesh, Gujrat Vidyapeeth, Ahmedabad India

Where: Alternative Energy Department, Gujarat Vidyapeeth, Ahmedabad

Who: Hiren Jayesh (one person) , Contact: http://www.facebook.com/hirenjayesh

When: Swaraj K3 batch’s Ahmedabad Learning Journey, August 22, 2012

1. Hand operated Blender / mixie

A hand operated drill attached; there are about 4~5 gear connections including one horizontal-to-vertical axis conversion. Results in very high number of rotations of the final blender end upon slow rotation of the handle.

Advantage vis-a-vis cycle-operated device: This is smaller, can fit easily inside a kitchen, close to where the cooking is happening. Doesn’t need legs, so more suitable for kids, senior citizens and people in sarees/lungis.

2. Pedal powered washing machine

A circular metal cage with holes is fitted inside a standard metal grain-storage box.

Advantage vis-a-vis another simpler model where a drum is directly attached to the shaft:

This takes care of the issue of leakage of water. The clothes and detergent are put inside the drum via a hinged hatch on the curved side (hence loading/unloading clothes is also easier than the model we have). The whole box is filled with water upto half the drum’s height. Thanks to the several holes, water enters the drum too. And then the drum is spun, making the clothes slosh in and out of the water. The only watch-out places for leakage of water are two small circular holes made on 2 sides of the box for fitting the shaft. And those spots are non-moving.

Since the drum is smaller, and not holding the bullk of the water, there is comparatively lesser inertia during rotation, making it easier for the user to halt and reverse direction.

3. Pedal powered car battery charger

A rubber belt tied around the bicycle wheel’s rim drives the dynamo. A normal cycling speed input generates 1100RPM at the dynamo end. Hiren has tested that an average user can run this for about 15 minutes before needing a break.

The dynamo generates DC (direct current) electric power. This is connected to a small voltage regulator that stabilizes the voltage at 14 volts. If the cycle speed (and hence output voltage) drops below a certain limit, the power supplied to the battery is automatically cut off by the regulator. If the cycle speed is excessive (due to an over-enthusiastic cyclist), then too the regulator limits the voltage to the battery at 14V (or something like that). This is done to prevent damage to the battery.

To use this stored energy, a separate DC circuit is connected to the car battery (when not charging) that would have some voltage-varying mechanism to supply power to any DC electronic devices like LEDs, mobile and laptop chargers. Simplest being a potentiometer, could use a chopper circuit to supply higher than 12V, or can connect two car batteries in series to make a 24V source. (We did not see/explore this part in our visit).

Note: It is not practical to invert this to 230V AC power (too much energy is wasted in storage then inversion to AC and then stepping up). Better in the longer run to re-design the devices we use to work around low voltage DC.

Specifications:

Dynamo : A permanent magnet DC motor/generator manufactured by Pranshu motors,


14 volt, 1100 RPM (revolutions per minute), 3.7 Ah (Ampere hour)

Manufacturer: Pranshu servo motors, http://www.pranshu.com/htm/contact.htm





Battery : 26 Ah (Ampere-hour), 12v standard car battery (Amaron)