Fig. 2,572.—General Electric external resistance and inductance for 110 volt synchronism indicator. Both the resistance and inductance are intended to be placed behind the switchboard.
Figs. 2,573 to 2,576.—Connections of General Electric synchronism indicator. Fig. 2,573, connections with grounded secondaries on pressure transformers; fig. 2,574, connections with ungrounded secondaries on pressure transformers; fig. 2,575, connections for 200 to 240 volt circuits, with six point receptacles; fig. 2,576, connections for checking location of needle. The various letters referred to in the diagrams will be found marked on the ends of the instrument studs and back of reactance coil box. It is important that the instrument be connected in circuit in the proper manner so that the needle will come to the mark on the upper part of the scale when synchronism is obtained. In case the pointer become moved or a change in its position be necessary, it is advisable to make a check on the indication before relocating the needle. This test can be made as follows: Connect together (fig. 2,573) studs marked B and E and connect stud A to terminal F on the external reactance box. When these connections are made, the instrument can be connected to a single phase circuit of normal voltage and if the instrument be correct, the pointer will stand vertically at the point of synchronism. If it do not, the needle can be moved and should be fastened in the correct position. The synchronizing lamps when connected as illustrated in the diagrams, show dark when synchronism is reached. This is the only connection possible when grounded secondaries are used, as in fig. 2,573, and for the high voltage indicators when used as in fig. 2,575, but with ungrounded secondaries (fig. 2,574) the lamps may be connected as indicated, when they will show bright at the moment of synchronism. The connections to the synchronism indicator remain the same as before.
Power Factor Indicators.—Meters of this class indicate the phase relationship between pressure and current, and are therefore sometimes called phase indicators. There are two types:
- 1. Wattmeter type;
- 2. Disc, or rotating field type.
Fig. 2577.—General Electric synchronizing receptacle and plug for use with synchronism indicator.
