kagdural history building 85 



running of the elevators, the ventilating fans, the machinery con- 

 nected with the handling of coal and ashes, the refrigerating plant, 

 the vacuum cleaning machine and the machinery required in the 

 shops and laboratories. The number of outlets for the attachment 

 of lighting fixtures is especially large, and their distribution is based 

 on a systematic plan. 



Machinery. — The electrical machinery consists of four engines of 

 the Eidgway Dynamo and Engine Company's make and four West- 

 inghouse 3-wire generators, and space has been reserved for the in- 

 stallation of an additional unit in the future should it be called for. 

 Three of the engines are of the 4-valve Corliss type, 19-inch bore and 

 18-inch stroke, without dash-pot cut-off, developing 250 horse power 

 at 200 revolutions a minute. The fourth engine is smaller, of the 

 plain slide valve type, 13-inch bore and 14-inch stroke, developing 130 

 horse power at a speed of 165 revolutions a minute. All of the 

 engines rest on splayed concrete foundations, 5 feet thick for the 

 larger ones and 4 feet for the smaller one, which are in turn under- 

 laid and surrounded by 1 foot of sand. The generators are direct 

 connected to the engines, the three attached to the larger engines 

 having an output capacity of 150 kilow^atts each, and the smaller one 

 of 75 kilowatts, at voltages of 115 and 230. The smaller engine and 

 generator are more especially designed for night service when the 

 building is not open. 



Switchboards and distribution panels. — The generator switchboard, 

 which is located at the western end of the engine room, receives the 

 cables from the generators through terra cotta conduits. The con- 

 nections from each generator comprise six cables of 900,000 circular 

 mils, four of 300,000 circular mils, and two No. 8 wires. This switch- 

 board consists of fifteen marble panels, assigned as follows : Four to 

 the generators now installed and one to the reserved unit; one each 

 to the lighting service of the four stories; one to the patrol and 

 rotunda lighting; one each to the fan and elevator services; one to 

 the older buildings and neutral service; one to tie and breakdown 

 switches; and one to miscellaneous use. The generators are so de- 

 signed that a 3-wire system is obtained without the usual balancer. 

 Current in the neutral is furnished by alternating collector rings on 

 the main generator, cables from which lead to auto-transformers 

 back of the switchboard. The voltage betw^een the outside leads is 

 230, while between the neutral and each of the outside it is 115. The 

 bus bars of the generator switchboard are so arranged that one engine 

 or any number of them can be nm on either the lighting or the 

 power bus bars, thus enabling the engineer to manipulate the lighting 

 and power systems entirely indei^endently of each other, and thereby 

 preventing undue fluctuation in the brilliancy of the lights when 

 loads are thrown on and off on the power end. So much of the 



