# I think i have flawed results and I need somebody's opinion.

I have been working on a small generator and i need a dynamo to generate the electricity so I did a little experiment to find out what motor i had was most efficient at generating power so I know what I should use a in the upcoming project. On each motor which was spun at the same speed by my Dremel all the results were ordinary except for one motor which surprised me with its super high reading. Upon seeing this I thought it might be my multimeter going dead and giving me false readings i changed out my multimeter and got the same exact readings for the motor. Is this because it really can produce 120 watts or am i doing something wrong? My formula for finding watts was V*A=W the motor was producing around 8.5 amps at 14 volts. I'm pretty sure the formula is correct as well. Help would be appreciated greatly thanks.

Harry

Harry

active| newest | oldesta.) Measured the voltage with a voltmeter, across the open terminals

b.) Measured the current into an ammeter directly across the terminals.

Right ?

When you measure current at zero voltage, you have no power.

What you CAN say is that the generator has an output resistance of opencircuit volts/ short circuit current.

If we take your numbers, you have 14/8.5 Ohms of resistance - for the sake of argument, we'll believe the current number, though that seems VERY high, unless this really was a drill motor. So you have 1.6 ohms of output resistance. The MAXIMUM power from the generator will be delivered into 1.6Ohms, and that will be = (open circuit volts/2)^2/1.6, about 30W.

http://www.nitroplanes.com/86ma15-2220-1880kv.html?gclid=CN_VsMPuwbsCFcU5Qgod9R0AdA

2. How are you measuring the amperage?

3. How are you measuring the voltage?