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namo unless lights are operated therefrom, in which case a switch and cut-out shall be placed in the main circuit before branching off to the various dynamos.
There shall be provided the following 46. convertnumbers and sizes of converters:
Each converter shall reduce the voltage on the primary circuit to volts
on the secondary circuit; shall have its capacity plainly marked upon it; and shall be provided with a separate fusebox which shall be so arranged that when replacing fuses or otherwise working about the converter the primary circuit may be opened.
(See p. 63, sec. 36.)
47. Cables to Switchboard.
48. Starting Plant and In■traction.
49. Renewal Parts.
so. summary. (See Note: p. 52, sec. 27.)
Each bidder shall fill out completely the following summary:
Number of alternators ....
Trade number or designation . .
Number of exciters
Trade number or designation . .
Rating of alternators in volts . .
Rating of alternators in amperes .
Rating of exciters in volts . . .
Rating of exc iters in amperes . .
Self or separately excited . . .
Reduction recommended in con-
H. P. required to be delivered at
the pulley at full load . . .
61'£f- (See p. 53, sec. 28.)
board A^pa- There shall be placed upon this switchconnections- board, in addition to the dynamo regulating apparatus, such switches, cut-outs and other appliances as are necessary for the proper and convenient manipulation of the circuits, such appliances to be named by each bidder in his proposal.
The appliances and connections shall be such as will permit the operation of any dynamo on any circuit or number of circuits, and the cutting in or out of any dynamo or circuit with certainty and rapidity without in any manner affecting the operation of other dynamos or circuits. (They shall also be arranged in such manner as to render it possible to connect two dynamos in parallel by an arrangement of switches or combination of circuits.) (For switchboard connections see sees. 30 and 31, pp. 55 and 56.)
(See p. 57, sec. 32.)
Alternating Current or Direct Current
This contractor shall furnish, and, unless otherwise specified, erect the following apparatus and material:
54. Dynamo(s). (See Note: p. 43, sec. 21.)
A dynamo capacity of, as nearly as possible, kilowatts. (The number of dynamos shall not be less than
, nor more than .)
The dynamo (s) shall be of the latest and most efficient pattern; shall be mounted upon a base provided with an adjustable belt tightener so that the belt may be tightened while in operation; capable of operating under full load for
consecutive hours without increasing
the temperature of any part, especially the armature, fields, and commutator, to such a degree as to endanger the insulation or decrease the efficiency of operation; shall not spark appreciably with proper care of the commutator and adjustment of the brushes, nor under considerable variation of the load; shall have an insulation resistance of not less than
ohms between all parts insulated
from each other; shall be adapted to operate at such speed as will allow the use of high-speed, automatic cut-off engines belted direct; shall be provided with efficient oiling devices; the armature shall be balanced electrically and mechanically so that there will be no tendency to spring the shaft, or to draw the armature toward either bearing so as to cause excessive friction and heating, and no vibration; all contacts, binding posts, brushes, etc., having considerable differences of potential between them shall be so placed and protected that the danger of receiving a shock is the least possible; armature conductors shall be so securely attached to the armature as to preclude any possibility of their being