. The Street railway journal . FIG. 9.—SUB-STATION AT ROCKAWAY JUNCTION similar. The fields are compound wound with the shuntwinding arranged for self-excitation. The machines are soover-compounded, that if operated as direct-current gen-erators at constant speed, the voltage will rise from 600 voltsat no load to 650 volts at full load. The converters are guar-anteed to stand overloads of more than 2^ times the normalload at 600 volts d. c. without falling out of step, providingthe e. m. f. at the alternating end is maintained within 14per cent, of the normal. Ample provision is made for ven-t
. The Street railway journal . FIG. 9.—SUB-STATION AT ROCKAWAY JUNCTION similar. The fields are compound wound with the shuntwinding arranged for self-excitation. The machines are soover-compounded, that if operated as direct-current gen-erators at constant speed, the voltage will rise from 600 voltsat no load to 650 volts at full load. The converters are guar-anteed to stand overloads of more than 2^ times the normalload at 600 volts d. c. without falling out of step, providingthe e. m. f. at the alternating end is maintained within 14per cent, of the normal. Ample provision is made for ven-tilation by passages through the armature core and windingsand also through the field coils. TRANSFORMERSThe transformers used with the converters are of the air-. -1^^ -?^-S^iS^!^?^S»» .-^•^t.^^y^ FIG. 10.—THE HAMMEL SUB-STATION with the floor line. It is entirely open below the commutatorso that there is easy access to the lower brushes from the pitin the interior of the foundation, which can be easily reachedfrom the basement. The looo-kw rotaries are rated to deliver 1600 amps, at625 volts, and 1667 amps, at 600 volts. The three-phase po-tential at the alternating end is approximately 370 volts, for625 volts at the direct-current end. blast type throughout. Those for the looo-kw rotary con-verters are grouped in banks of three 375-kw transformersto one rotary converter. For the 1500-kw converters theyare in groups of three 550-kw each. The high-tension winding is designed for a normal e. m. 12,000 volts, with taps arranged to enable other voltagesto be utilized down to 10,000 volts. The low-tension windingis designed to normally carry 400 volts, with taps which will 974 STREET RAILWAY JOURNAL. [Vol. XXVIL No. 25. enable other volt
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
