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The dynamo(s) shall be rated vrith such margin of safety that }* | shall not be
injured if subjected to a temporary overload of -— per cent. above such rating.
(Note.—In the specification for foundations it should be borne in mind that a dynamo is not subject to vibration if its armature is properly balanced, nor to the strains and shocks due to the movement of rapidly reciprocating parts, it is therefore only necessary to provide such foundation as will amply sustain its weight and resist the belt strain.)
approval of the | . | and shall be of
sufficient length, width and depth to safely
and firmly sustain } tor | weight.
removal of all débris shall be done by the
contractor. . }. ! The height of the dynamo
base-frame(s) above the ground will be —.
The dynamo base-frame(s) shall be firmly and securely fastened to the (se) foundation(s) in such a way as to prevent lateral motion in either direction, and to give an even bearing surface at every point,
(Note.—This specification simply provides 28. Instrufor such instruments as it is customary to fur- lanell t S. nish with a dynamo; if extra instruments are desired, such as portable voltmeters, portable ammeters, testing sets, etc., they should be distinctly specified, as well as the make if a particular kind is preferred.)
There shall be provided with each dynamo one hand regulator for adjusting the pressure, made entirely of incombustible material; one ampère meter for indicating the current supplied by the dynamo and graduated to read ampères; one voltmeter or pressure indicator, which shall remain constantly in circuit, so as to indicate continuously the pressure at the point to which it is connected, and which shall be so constructed that the scale is plainly visible at a distance of at least ——; one brush jig for trimming the brushes; one insulating baseframe provided with rails and a suitable device for shifting the position of the dynamo to alter the belt tension; and one headboard switch for cutting off the current at the dynamo itself. There shall also be provided for the installation — ground detector(s), which shall continuously indicate the insulation from the ground maintained on both sides throughout the system, and — lighting arresters of the most efficient type known.
(Note.—In the case of compound dynamos 24. Cables to operating in parallel the equalizing wire may i. often more conveniently be carried direct
25. Starting Plant and Instruction.
from dynamo to dynamo, in which case this contractor should furnish and connect a suitable equalizing switch at each dynamo.) This contractor shall carry to the switchboard location at — all regulator and main wires, leaving the ends coiled up neatly, properly tagged, and sufficiently long to make the necessary switchboard connections. All main wires shall have a capacity of at least — C. M. per ampère, and no wire smaller than —— B. & S. or B. W. G. shall be used. Regulator wires shall be covered with — insulation, and shall be
cleated to the ceiling, carried on insulators, main wires shall be concealed in molding;
of bare copper wire supported ! on porcelain insulators.
carefully cleated to the ceiling, wire
| or insulated
carried on porcelain insulators, concealed in molding consisting | of a backing — thick and a capping
U— thick wires of opposite polarity being separated not less than —. In no case shall insulated
wires be carried in such proximity to heated surfaces, vapors, or air as to endanger their insulation.
When the plant shall be ready for operation the dynamo(s) shall be run for a period of — days by competent engineers furnished by the contractor. All oil, waste, power, etc., to be furnished by (the purchaser). This contractor shall also give all necessary instruction to the engineer of (the purchaser) for the proper care, maintenance, and operation of the dynamo(s), such instruction to be given during the trial period stipulated above.
This contractor shall furnish such renewal parts as it is advisable to keep on hand, adding hereto an itemized list of same.
(Note.—The object of this summary is to present in a concise, tabulated form, the essential data concerning the apparatus to be supplied, thus enabling the different bids to be easily and quickly compared. For complete plants a single form, systematically arranged, will be found extremely convenient both in making comparisons and in being able to see at a glance just what apparatus and appliances are called for, thus constituting a check on the specifications themselves.)
Each bidder shall fill out completely the fol-
Shunt or compound . - -
Make of lamp recommended for use .
Dynamo capacity in – c. p. lamps of the above make .
Speed . - - t e
Size of pulleys . .
26. Renewal Parts.
27. Summary. 28. Switchboard.
H. P. required to be delivered at the
Switchboard and Appliances.
This contractor shall furnish and erect the following apparatus and material:
(Note.—In plants of any considerable size the switchboard specification is an extremely important one. Its general characteristics will be determined by questions of purpose, economy, utility, available space, beauty, etc., but the details of material, method of wiring, attachment of instruments, location, number of switchboards, etc., demand the most careful study. It may be advisable in one instance to have a single switchboard controlling everything from a single centre, in another to have a dynamo switchboard and a separate circuit switchboard, while in yet another to even divide the dynamo switchboard into two or more parts and to have several circuit switchboards. In determining the location of switchboards, not only should questions of convenience be considered, but also questions of its relation to economy in the wiring ; the example given on p. 22 illustrates this. Upon the arrangement of the instruments will depend the facility and certainty with which they may be operated.)
The switchboard shall be made of ——, neatly and substantially built, of sufficient