Electromagnetic Hand Cranked Generator

In this project we plan to demonstrate that it is possible to create electricity from a hand cranked generator that spins magnets in a coil of copper wire.
Grade 6

Hypothesis

It is possible to design a hand-cranked magnetic generator that can create a strong enough moving magnetic field to generate sufficient electrical current to light a light bulb. 

Research

Before starting to design our hand-cranked generator, we will conduct internet research to see if other people have created hand-cranked generators similar to what we plan to make. We will study their designs to help to answer our main design questions:

1. What magnets will be required? 

2. How fast should the magnets spin? Are gears necessary to make the magnets spin faster? What material should the gears be?

3. What should the base/structure be made of?

 

Variables

1. How fast should the crank be spun? Does it depend on the person cranking the generator?

2. How many loops of wire should be coiled to generate sufficient current?

Procedure

First, we did research on whether anyone else has done something similar to this and what were their designs. 

Second, we chose the design option: set up a magnet on an spinning axle, build a structure to support the axle, coil wire around that same structure.

Third, we assembled the generator.

Fourth, we tested the generator by different operators (people) and different numbers of coil loops and record the voltage that they generate.

Observations

1. First attempt: We built the generator using a hardboard structure taped and glued together, with an axle and gears out of Lego and the strongest house magnets we could find. We coiled 200 loops of copper wire around the structure. Testing with a multimeter, we measured a maximum generated voltage of about 200 mV, which is likely insufficient to light a light bulb. We also observed that the hardboard structure was not very stable and likely to collapse when cranking rapidly or when coiling additional loops of wires too tight.

2. Therefore, we decided to start over with a second attempt, in which the entire structure was made out of Lego. We used the same magnets and axle, but in response to our previous observations, we decided to use 1000 loops of wire.

We then asked different people to crank the generator as fast as possible and recorded the maximum generated current and voltage over a 10-second time period. The results are as follows:

 

Trial Number Who turned the crank Current generated Voltage Generated
1 Elijah's Dad (30+ year old) 53.2mA 1,42V(max)
2 Philippe (11 year old) 25.3mA 1.0V (max)
3 Elijah (11 year old) 24.6 mA 1.1V (max)
4 Philippe's Dad (30+ year old) 30.1mA 1.0V (max)
5 Karl (7 year old) 8 mA 0.87 V (max)
6 Zoe (19 year old) 18mA 0.9V
7 Elijah's mom 22mA 0.9V


The generated voltage of 1 V or more is sufficient to light a light bulb.

 

 

Analysis

After we conducted all of our trials, we found that the hardboard walls of our first generaror caved in and, after the crank came off, we abandoned that design. Very little voltage was generated (~ 200 mV), we think it was because there were'nt enough coils of wire.

For design number two we desided to use lego for the gears and the base because it is very precise and stable. We decided to use both the big and the small magnets. We also made a crank out of Lego. Based on the observation that 200 loops of wire generated ~200 mV, we decided to use 1000 loops in our second design in order to generate ~1 V.

Conclusion

In conclusion, we found that it was possible to design a hand-cranked magnetic generator that can create a strong enough moving magnetic field to generate sufficient voltage (~1 V) to light a light bulb. 

Application

It can be used in emergency situations to power small objects and during a power outage it can charge a phone or flashlight.It is useful while camping and when you are off-grid.

While our prototype generated enough power to light a light bulb, it is possible to generate even more power by adding even more coils of wire and by spinning the magnet even faster (by increasing the gear ratio).

Sources Of Error

Stability of the design (wobbly crank, structure unstable) 

The voltage generated varies according to the speed of cranking. Someone cranking it too slow may not generate enough power, but someone cranking it too fast may burn out the light bulb. We settled on a design in which an average adult could generate the appropriate voltage while cranking at a comfortable speed.

Citations

Hornof, J. (2024, February 28). How to Make a Simple Electric Generator: 10 Steps (with Pictures). wikiHow. https://www.wikihow.com/Make-a-Simple-Electric-Generator.                    

 

McCloy, J. (2021, November 26). 5 Best Hand Crank Generators in [currentyear] [Buying Guide]. Green Coast. https://greencoast.org/best-hand-crank-generators/.                        

 

I. (2017, September 20). Hand Crank Generator. Instructables. https://www.instructables.com/Hand-Crank-Generator/

Acknowledgement

We would like to thank Philobateer Ghaly and Pierre Levan for there mentorship and tutoring for this project. 

We would like to thank our parents for helping us to purchase the necessary supplies, to pay for the tutor, for registering us for the science fair, and for supporting us to complete the project.