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The dynamo(s) shall be rated with such

margin of safety that j ^.ey 1 shall not be

injured if subjected to a temporary overload of per cent. above such rating.

M.«oL"d*" (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.) The foundation(s) for the(se) dynamo(s)

Shan be built bythe j-—| °f ~

laid , or of other material subject to the

approval of the {^tect, f and shall be of sufficient length, width and depth to safely and firmly sustain j *^jr | weight.

All necessary excavating or filling, and the removal of all debris shall be done by the

{puSi?: 1 The hei^ht of the d^amo

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 23. instmfor such instruments as it is customary to furnish 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 ampere meter for indicating the current supplied by the dynamo and graduated to read amperes; 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^), 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. Cuiiics to operating in parallel the equalizing wire may board, often more conveniently be carried direct

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 ampere, 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; )

f j bare copper wire supported ) insuiate(i 01 j on porcelain insulators. j 01 insulaTea

carefully cleated to the ceiling, carried on porcelain insulators, wire < concealed in molding consisting of a backing — thick and a capping — 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.

25. starting When the plant shall be ready for operation 1 struc'tiou." the dynamo(s) shall be run for a period of

days by competent engineers furnished

by the contractor. All oil, wpste, 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 I during the trial period stipulated above.

This contractor shall furnish such renews! 26, J?*^wal parts as it is advisable to keep on hand, adding hereto an itemized list of same.

(Note.—The object of this summary is to 27. summary, 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 following summary:

Number of dynamos . . .

Trade number or designation . .

Rating in volts

Rating in amperes ....

Shunt or compound ....

Make of lamp recommended for use .

Dynamo capacity in c. p. lamps of

the above make ....

Speed .... ...

Size of pulleys ..... M -1

H. P. required to be delivered at the
pulley at full load with no loss in
the feeders

Switchboard and Appliances.
This contractor shall furnish and erect the
following apparatus and material:

28'boar<ich (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 th» 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

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