how many watts of electricity ia a man capable of producing by turning a handle or peddling a machine connected to an alternator
2006-12-02 02:43:45 · 8 answers · asked by rocky 3 in Science & Mathematics ➔ Engineering
I am building an alternator from scratch and I want a comparison to test its efficienty when opperated by man
2006-12-02 03:03:49 · update #1
I decided to carry out an experiment to try and offer some data to answer this question.
Firstly I measured how far my head travels when I go from a squatting to a standing position. This came out at a dissapointing 0.6m (I guess I've got short stumpy legs).
Next, I loaded up a backpack with as much junk as I could carry.
This came out at 30kg (again disappointing).
Next I put on the backpack and weighed myself. This came to 120kg. I'm assuming that my legs constitute 1/3 of this weight, so I subtract this from the final calculations: 120 - 40 = 80kg lifted.
Next I started a timer and began counting squats until I was so out of breath and my legs hurt so much that I couldn't continue.
I did a dissapointing 15, and it took me 70 seconds.
After I'd got my breath back (about two days later), I calculated the power generated during this little exercise.
I'm assuming a constant force, and neglecting any acceleration except gravity. Also, I'm taking g = 10m/s^2 to make the hard sums easier, this makes 80kg equivalent to 800N
Energy = Force * Distance
800N * 0.6m * 15times = 7200joules
Power = Energy / time taken
7200 / 70 = 103 Watts
Obviously there are some assumptions in this experiment and I doubt wether loading up to the max had me operating at peak efficiency, but this at least gives you some empirical data to work with.
Best regards.
2006-12-03 22:09:54 · answer #1 · answered by chopchubes 4 · 0⤊ 0⤋
You can convert horsepower to watts and apply the efficiency of your generator.
Most people cannot generate more than about 1/4 horsepower consistently, or 1/2 horsepower in a short, frenzied burst.
Also - your load on your pedals (if it is a pedaling machine) will vary according to your electrical load. If you connect the terminals of the generator - shorting it out - your pedal effort will be surprisingly low. Disconnect the terminals and you will feel like you hit a brick wall. The point being - gear the thing to optimize the leg speed of your peddler.
There is exercise equipment out there that operates using this principle.
2006-12-02 03:16:39 · answer #2 · answered by www.HaysEngineering.com 4 · 1⤊ 0⤋
150 watts is a good order of magnitude estimate. To actually answer the question you asked requires knowing not only the power output the human is capable of but also the losses in your mechanical setup. Also consider that human power capability is strongly influenced by the duration of the task.
For more:
http://msis.jsc.nasa.gov/sections/section04.htm#_4.10_WORKLOAD
2006-12-02 06:11:42 · answer #3 · answered by AnswerMan 4 · 0⤊ 0⤋
Most people can pedal consistently at about a quarter horsepower.
1 horsepower is 746 watts.
So a quarter of that is 186.5 watts.
2006-12-02 03:29:53 · answer #4 · answered by anthony e 2 · 1⤊ 0⤋
You produce about 100 watts just existing.
2006-12-02 02:55:31 · answer #5 · answered by lulu 6 · 0⤊ 1⤋
For you about 365 watts, for an athlete about 50,000 watts.
2006-12-02 02:51:25 · answer #6 · answered by spir_i_tual 6 · 0⤊ 1⤋
That depends on the alternator, how fast he is turning the handle, and how long he turns it for
2006-12-02 02:46:40 · answer #7 · answered by Dan-yul 2 · 0⤊ 1⤋
120 watts?
2006-12-02 03:10:31 · answer #8 · answered by spidermandan673 2 · 0⤊ 1⤋