[Photo: Stationary Armature Frame of 3500 Kw. Three-Phase Alternator: original size (20K) | 4x enlarged (64K)]
Some of the most interesting work which has been done by the General Electric Company in recent years has been in the production of very large machines, many of which are designed for very high voltages. The 10,000 H.P., 10,000 volt generators now in production for the Canadian Niagara Falls Power Company are the largest electrical machines ever produced. These machines operate at 250 revolutions per minute, an unusually high speed for a machine of such large capacity. Their over all dimensions arc consequently much less than those of many generators of much smaller capacity which operate at lower speeds. Contrary to the regular practice of the Company to test each machine before shipment, these machines are not assembled at Schenectady, the weight of assembled parts — the 141,000 pound motors, for example — being too great for shipment. Accordingly, the parts are made in Schenectady and are put together at Niagara Falls.
[Engraving: 3750 Kw. Four-Phase Alternator Built for Niagara Falls Power Co.: original size (10K) | 4x enlarged (31K)]
[Drawing: Cross-Section Assembly of 10,000 H.P., 10,000 Volt Generator Building for Canadian Niagara Falls Power Co.: original size (27K) | 9x enlarged (126K)]
The generator of largest dimensions so far completed at Schenectady, was recently shipped to the Philadelphia Electric Company. It is 33 feet in diameter, has 96 poles and generates 5000 Kw., at 6000 volts, 60 cycles and 75 revolutions per minute.
[Photo: 2700 Kw. Railway Generator Built for Boston Elevated Railway Co.: original size (14K) | 4x enlarged (47K)]
Among other very interesting machines recently produced may be mentioned the 2700 Kw. direct current machine built for the Boston Elevated Railway Company, and a 2500 Kw. double current generator built for the Chicago Edison Company. The former machine is 27 feet 8 inches in diameter, operates at 575 volts and 75 revolutions per minute, and is designed for heavy overloads. The double current generator in Chicago delivers its full output and heavy overload either in alternating or direct current, the direct current voltage ranging from 250 to 300. Its over all diameter is 28 feet 8 inches. Both of these machines are highly efficient and operate at low temperatures with very perfect commutation. Among large motor-generators may be mentioned a 1000 Kw. unit driven at 300 revolutions per minute by an 11,000 volt, 1400 H.P. induction motor. An 800 H.P. induction motor for 180 revolutions per minute has recently been supplied to the Anaconda Copper Mining Company.
Four 2500 Kw., 240 volt rotary converters, 17 feet in diameter over all, and having 13-foot armatures running at 115 revolutions per minute, have recently been completed.