GB190226380A - Improvements in Automatic Electric Potential Regulators. - Google Patents

Abstract

26,380. Carolan, E. A., [General Electric Co.]. Nov. 29. Dynamos, regulating.-Fig. 1 shows a regulator, and Fig. 2 a diagram of the connections, for an alternating-current generator, the variations in the voltage of the generator automatically varying the resistance in the field of the exciter. A field coil I produces a magnetic field varying with the voltage of the generator, and may have a laminated magnetic core with a central member 3 extending through the coil and with branches 4, 5 passing round the bottom and sides. A movable coil is carried by an open frame 8, 9 secured to a cross-bar 10, which is pivoted between standards 11, 12 carried by the base 13. A spring 14 carried by a standard 15 engages a cross-bar 16, and damps out vibration due to the alternating character of the current. An adjustable spring 17 is connected at one end to a bell-crank lever 18 secured to the bar 10. The lever carries a contact 19, which makes contact with an adjustable fixed contact 20. In the arrangements shown in Fig. 2, the transformers 29, 30 supplying lamps 27, 28, motors, &c. are connected across mains 25, 26 from the generator 22. The exciter with an armature 31 and a shunt field winding 32 and series resistance 33, supplies current to the field winding 23 in series with a regulating-resistance 34. The coils 1, 2. Fig. 1, are represented by the coils 35, 36, Fig. 2, which are in series with a resistance 37, and are supplied with current from a transformer 38, or directly from the mains 25, 26. When the voltage increases slightly across the mains, the contacts 19, 20 are opened, and the short-circuit across the resistance 33 broken, causing a sudden increase in the resistance in the field winding 32, thereby decreasing the voltage of the exciter, and hence that of the generator. The contacts 19, 20 then close, and the short-circuit across the resistance 33 is again made. The alternate opening and closing of this short-circuit goes on rapidly in practice, whereby the voltage is held practically steady.