How to Convert a DC Motor into a Generator

How to Convert Any DC Motor into a Generator

First,you must understand and appreciate Faraday’s laws of electromagnetic  induction that shows the relationship between electric circuit and magnetic field. Thus,Faraday concluded that whenever there is relative motion between conductor and a magnetic field, the flux linkage with a coil changes and this change in flux induces a voltage across a coil.To convert, It is very simple you only need to understand that a basic DC motor and a basic DC generator is the same thing. Such that, if you apply a voltage to the winding, it's a motor; the current flow through the winding thus causing the shaft to rotate. And if you apply a mechanical force to the shaft you cause it to rotate, and it's a generator; a voltage will appear across the winding's, and can drive an electrical load.
DC motors are different from induction motors in that they have permanent magnets in place already. Hence, you need not to do anything to them for them to generate electricity for you. However, they will produce AC current, so you will have to use diodes to rectify or change the current to DC. Another problem with using a DC motor is that the brushes do wear out and you’ll have to do some maintenance.The DC motors to work you need to understand its rated Rotations per Minute and Voltage. For instance, if a DC motor is of very high speed you will have to use a gear box or other mechanical way to increase the speed but this isn't good for stability. Otherwise it won't generate even 0.5 Volts at low rotation speed. The rated speed should be about 2900 rpm at full, the lower the speed the better. The motor generate a voltage near the rated voltage.