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and precaution, to add to or take away from the circuit any dynamo without in any manner affecting the operation of the remainder, or causing any change in the candle-power or steadiness of the lamps; and that when two or more are operating on the same circuit in parallel the load may be divided between them in proportion to their respective capacities under all conditions, from no load to full load; and that with the proper connections any number of pairs, a pair consisting of two similar dynamos, may be manipulated in the same manner and with the same effect as single dynamos, as indicated above.
Thedynamo(s) shall be rated with such
margin of safety that j j- shall not be
injured if subjected to an overload of
per cent, above such rating for a pe riod of .
22. t Founds- (Note.—The following specification is for foundations for belted dynamos; while the dynamo foundation need not be as massive as the engine foundation it should, nevertheless, be of ample dimensions.
For direct-connected outfits the foundation is the engine foundation sufficiently enlarged to also support the dynamo and therefore is properly included under the head of engine foundation.
For either purpose the foundation should be entirely separated from walls, floor or sub-stratum of rock by some deadening material such as felt, cork, or sand.)
The foundation(s) for the(se) dynamo(s) shall be built by the j TM£ [ of— laid , or other material subject to the
approval of the j ^S, [ and sha11 be of sufficient length, width and depth to safely and firmly sustain j | weight.
| ^It^ | sba^ be msula^e(i and isolated in the following manner: , so that
no vibration or noise whatsoever shall be transmitted to any part of the building.
Above the floor line j th£y I shall be
faced with .
All necessary excavating or filling and the removal of all debris shall be done by
the floor in the following manner .
The height of the dynamo base-frame(s) above the floor line 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.
23-Jnstrn. (Note.—This specification simply provides for such instruments as are actually necessary for operating the 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 may 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; and one insulating base frame provided with rails and a suitable device for shifting the position of the dynamo to alter the belt tension. 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 type.
itrttStoSd." (Note.—In the case of compound dynamos operating in parallel the equalizing wire may 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
f cleated to the ceiling,
shall hp nf i bare c°pper wire supported |