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again inserting the resistance in the field circuit. One of the main features of this regulator (Fig. 218) is that the contacts which shunt the resistance in series with the field winding in and out of circuit are continually shifting, and do not regularly make contact at the same point. Each contact is mounted on a thin, straight spring which is fixed at the end opposite the contact.
The reeds carrying top and bottom contacts are mounted at a 90 degree angle so that the point of contact continually shifts because of vibration and resulting oscillation of the contact. Continuous vibration is obtained because one of the contact reeds is mounted on a regulator armature which vibrates at a high rate of speed. The shifting of the contacts prevents the formation of minute projections on the negative contact and corresponding re
cesses in the positive contact, with the result that the contacts never stick.
Wear manifests itself by the positive contact becoming thinner and the negative growing thicker. Periodically, a disconnecting plug is turned in its socket which reverses the polarity of the
Fig. 221.–View Showing Construction of Bijur Automatic Current
contact so that metal which has been deposited from one contact to the other is returned. The regulator vibrations do not take place at irregular or haphazard intervals, but in the order of something like 100 to 150 times per second. The resulting voltage is the resultant of a series of fine ripples above and below the mean value for which the regulator is adjusted. The amplitude
of these waves is very small, and as the frequency is high, satisfactory lighting can be done directly from the generator with no battery connected to the circuit. The generator is connected to the battery, however, and all lights and other electrical devices take their current from the battery terminals. The arrangement of the voltage regulator is such that a discharged battery is charged at a rapid rate while the charging rate tapers off as the battery becomes charged. This is clearly shown by the curve sheet C-4,
at Fig. 219. It will be observed that at the beginning of the charging process with the battery practically discharged, a charging rate of 16 amperes was obtained, at the end of one hour, but 14.2 amperes were delivered to the battery. At the end of three hours the charging current had tapered down to 11.3 amperes. At the end of eight hours but 612 amperes was flowing to the battery. In thirteen hours time the minimum charging rate of 434 amperes had been reached.
In the constant voltage equipment the automatic switch, vol. tage regulator and field resistance unit are mounted in an alu
minum box carried at the top of the generator, as shown in Fig. 220. This box is held in place by a single knurled nut and by three connecting pins or plugs which fit into receptacles in the generator. The two wires leading from the generator are soldered into a connecting plug, which in turn fits into a receptacle of the regulator box. The regulator mechanism can be changed readily by anyone, as no electrical or mechanical knowledge or skill is
required. In Fig. 221 the regulator box is shown with the cover removed, which exposes the automatic switch and the field resistance. This also shows an end view in which the connecting pins are shown, and a view of the disconnecting and reversing plugs also. An amperemeter is used in some of the Bijur systems, such as that at Fig. 168, B, which shows the wiring diagram of a Packard six-cylinder car, and in Fig. 222, which shows the system used on the Packard Twin Six. The amperemeter is con