2.  Strength of the electromagnet (the stronger the  magnetic field, the greater the induced voltage) 3.  Speed of rotation of the conductor or magnet (the  faster the rotation, the greater the induced voltage)  Position 2 Position 3 Position 4 Position 1 Position 5 Figure 9-10  illustrates the basics of a rotating machine used  to produce voltage. The simple generating device consists  of a rotating loop, marked A and B, placed between two  magnetic poles, N and S. The ends of the loop are connected  to two metal slip rings (collector rings), C1 and C2. Current  is taken from the collector rings by brushes. If the loop is  considered as separate wires, A and B, and the left-hand rule  for generators is applied, then it can be observed that as wire  B moves up across the field, a voltage is induced that causes  the current to flow towards the reader. As wire A moves down  across the field, a voltage is induced that causes the current to  flow away from the reader. When the wires are formed into  a loop, the voltages induced in the two sides of the loop are  combined. Therefore, for explanatory purposes, the action  of either conductor, A or B, while rotating in the magnetic  field is similar to the action of the loop. Figure 9-11  illustrates the generation of alternating current  (AC) with a simple loop conductor rotating in a magnetic  field. As it is rotated in a counterclockwise direction, varying  voltages are induced in the conductive loop.  conductor advances from position 1 to position 2, the induced  voltage gradually increases.  The conductor is now moving in a direction perpendicular  to the flux and cuts a maximum number of lines of force;  therefore, a maximum voltage is induced. As the conductor  moves beyond position 2, it cuts a decreasing amount of flux,  and the induced voltage decreases.  At this point, the conductor has made half a revolution and  again moves parallel to the lines of force, and no voltage is  induced in the conductor. As the A conductor passes position  3, the direction of induced voltage now reverses since the A  conductor is moving downward, cutting flux in the opposite  direction. As the A conductor moves across the south pole, the  induced voltage gradually increases in a negative direction  until it reaches position 4. Like position 2, the conductor is again moving perpendicular  to the flux and generates a maximum negative voltage.  From position 4 to position 5, the induced voltage gradually  decreases until the voltage is zero, and the conductor and  wave are ready to start another cycle.  The curve shown at position 5 is called a sine wave. It  represents the polarity and the magnitude of the instantaneous  The conductor A moves parallel to the lines of force. Since  it cuts no lines of force, the induced voltage is zero. As the  Figure 9-10.  Simple generator. N S N S Brushes Direction of rotation Collector rings C 1 C 2 A B B A A B Direction of movement  of the loop  through the  magnetic field Cross section of loop Current flow is away from reader Current flow is toward the reader Side of loop Side of loop + + 9-7