DC Motor As a Generator

About: Electrical Engineer
The DC motor is a ready made generator that will generate electricity. All that you have to do is turn the Axle of the generator using a mechanical outside source of energy .

To show that I dismantled a damaged HP printer and take  the  DC motor that responsible for paper out shown in pictures and connect it  to LED array ,  4 LED connected in a specific polarity and the other four LED connected in reverse polarity ,so when the shaft rotate on clockwise ,4 LED will be on due to  forward bias and the other  off due to reverse bias  and vise versa  in case of anti- clockwise rotation.




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    13 Discussions


    5 months ago

    sir you mean anything dc motors can produce electricity by rotating the axle on it
    if this true i uses small dc motor found on most.appliances and all i have to do is to rotate the rotor of it, so i use a magnet to produces magnetism in the axle of the dynamo outside part of it and lets say it will continue to rotate
    in the terminal of the dynamo I'llput led either 1.5 volts will it light up and if will, is it AC or DC


    Question 8 months ago

    Hello sir...how can we calculate the voltage produced by the DC motor at a specific rpm...or torque applied?

    1 answer
    Jack A LopezVarunS120

    Answer 8 months ago

    I expect the time-averaged, open circuit voltage, across the terminals of a brushed DC motor, will be directly proportional to the angular speed (in rad/s or rev/min = RPM) at which the rotor is turning. I mean, I expect an expression like:

    avg(Voc) = K*w

    where w is the angular speed of the rotor, and avg(Voc) is the time averaged open circuit voltage seen at the terminals, and K is some constant that depends on the construction of the motor itself.

    Moreover, I claim that you find that same K, in the case of running the motor as a motor, with no mechanical load.

    I mean, if I were to drive the motor with a a constant voltage source V1, and measure the no-load speed w1, I would expect to find the same K.

    V1 = K*w1

    Or trying this with a set of data points:
    {0, V1, V2, V3, ...} as input
    {0, w1, w2, w3, ...} as output

    I would expect the plot to look like a straight line, with slope K.

    I am guessing the result would look similar for an experiment that drives the motor shaft, using a mechanical power source, and measures output voltage across the terminals.


    1 year ago

    I believe it will produce a DC current.

    rohan lawande

    2 years ago

    So when it is used as generator will it produce AC or DC?

    hari sundar pyda

    3 years ago

    can this energy be stored in a battery

    instead of rotating it can we use a shaft and rotate the gear WHILE WALKING

    2 replies
    moodys2hari sundar pyda

    Reply 2 years ago

    offcourse this energy can be stored in a battery using Diodes.

    shomashari sundar pyda

    Reply 3 years ago

    "can this energy be stored in a battery" Yes.

    I would suggest a bridge rectifier whether you spin this in either just one or both directions because it will also functions as a blocking diode to prevent your batter from discharging into the motor.

    Instead of a battery, you might consider more efficiently storing the energy in capacitors that can cycle many more times than rechargeable batteries. Although capacitors will store less overall energy, they can have much greater power output than batteries of the same size because of their extremely low internal resistance.

    Furthermore voltage regulation is strongly recommended to prevent over charging battery or capacitors.


    3 years ago

    can i use starter motors as generator when the shaft is rotated..


    4 years ago on Introduction

    Thanks exactly what I wanted to know!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    I'm going to add it to my windmills!


    4 years ago on Introduction

    The motors found in printers are often stepper motors, and will generate more electricty at low speeds than the kinds you find in lets say a remote control car. Those are meant for higher RPMs when used for power generation.

    Mr. EE, I was just a Tech here, there, and yonder. Thanks for your efforts and full speed ahead on some more ibles. I try to always minimize the negative and Focus on the positive. Every ible has some positive about it. Critics please pay attention, May my words always be tender and soft, that makes them easier to swallow.Gyro.