# How could a DC electric motor be used to power a computer?

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1. Dec 14, 2016

### angie19

1. The problem statement, all variables and given/known data
A group of students found an old DC electric motor in a box. They were looking for a small generator they could use to power their computer while they were out camping.
Explain how they might do this with the motor they found.

2. Relevant equations

3. The attempt at a solution

2. Dec 14, 2016

### Daniel Hendriks

A motor is also a generator

3. Dec 14, 2016

### Staff: Mentor

Angie, you need to fill out all 3 sections of the Template. Please post some Relevant Equations (voltage, power, etc.), and show your initial thoughts on how to answer this schoolwork question. Thank you.

4. Dec 14, 2016

### angie19

Im finding this really hard trying to post a question

5. Dec 14, 2016

### Staff: Mentor

How can we help?

6. Dec 14, 2016

### angie19

I am trying to ask a question I do not get these templets I have to fill out

7. Dec 14, 2016

### Staff: Mentor

So when first posting your question, just try to fill out all 3 sections as best as you can, especially the Attempt at a Solution.

For now, don't worry about going back to try to edit your first post. Instead, just tell us some of your thoughts on how you could answer the question. How would you provide power to the motor? What affects the output voltage of the motor when you spin the shaft? How would you convert that output voltage to something that a computer could use?

How much power does a typical laptop computer require? What is the typical efficiency of a generator (or a motor being used as a generator)? How much input mechanical power would be needed to spin the motor shaft?

8. Dec 14, 2016

### cnh1995

I think this question is designed to make you think about how a dc motor could be used as an electric generator. Would it be an acceptable (and sufficient) answer? Or are you supposed to show the exact circuitry and calculations?

9. Dec 14, 2016

### angie19

what i have so far is low end of power consumption for a lab top is 12 wh of electricity, what I gather from this question is trying to figure out how this dc generator could be applied in order to produce power

10. Dec 14, 2016

### Staff: Mentor

Power is just in units of Watts, not Watt*Hours. Energy is power * time, so if you were looking at batteries, you would size their energy storage in W*Hr to see how long they could power the load.

So is the laptop you are looking at 12W? That sounds low, but maybe it's possible.