Nikola Tesla - Free-Energy Devices

A UXILIA R Y BR U8U REG ULA TION. 439the electric devices that may be employed for automaticallyadjusting the brushes, and Fig. 258 is a diagram illustrating thepositions of the brushes when the machine is being energized atthe start.a and 5 are the positive and negative brushes of the main orworking-circuit, and c the auxiliary brush. The working-circuiti) extends from the brushes a and b, as usual, and contains electriclamps or other devices, D', either in series or in multiplearc.M M' represent the field-helices, the ends of which are connectedto the main brushes a and 5. The branch or shunt wirec' extends from the auxiliary brush c to the circuit of the fieldhelices,and is connected to the same at an intermediate point, v.H represents the commutator, with the plates of ordinary con-FIG. 253.struction. When the auxiliary brush c occupies such a positionupon the commutator that the electro-motive force between thebrushes a and c is to the electro-motive force between the brushesc and b as the resistance of the circuit a M c' c A is to the resistanceof the circuit b M' c' c B, the potentialsof the points x and Y willbe equal, and no current will flow over the auxiliary brush ;butwhen the brush c occupies a different position the potentials ofthe points x and Y will be different, and a current will flow overthe auxiliary brush to and from the commutator, according to therelative positionof the brushes. If, for instance, the commutator-spacebetween the brushes a and c,when the latter is at theneutral point,is diminished, a current will flow from the point Yover the shunt c to the brush thus J, strengtheningthe currentin the part M', and partly neutralizing the current in part M but;if the space between the brushes a and c is increased, the cur-