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engine shaft or connecting engine and dynamo shafts by a coupling; the outboard bearing; the method of supporting the fields; the brush-holder support; the extended foundation box, and the speed.
It should also be mentioned where and by whom the dynamo is to be connected to the engine; how the freight and handling charges are to be divided; and where and by whom tests of the combination, if any are to be made before erection, are to be conducted.)
direct current, constant potential dynamo(s) (each) having a normal
capacity of amperes at volts.
The (se) dynamo (s) shall be
( shunt wound; / j compound wound;}
of the latest and most efficient pattern; mounted on 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 ins ulation or decrease the efficiency of operation; shall not spark appreciably with proper care of the commutator and adjustment of brushes, nor under considerable variation of 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 both 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; the dynamo(s) shall be so designed that with the proper connections any number may be operated in parallel of whatever ampere capacity, provided the voltage be the same; that when connected so to operate it shall be possible, with ordinary care 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 ^y j- shall not be
injured if subjected to an overload of
per cent, above such rating for a pe riod of .
S2'tionsIlda" (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) *aU be built by the [of—
laid , or other material subject to the
approval of the j « [ and shall be of sufficient length, width and depth to safely and firmly sustain j | weight.
| ^t^ [ s^a^ ^e msulated and isolated in the following manner:
, so that
no vibration or noise whatsoever shall be transmitted to any part of the building.
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. instru. (Note.—This specification simply pro
vides for such instruments as are actually necessary for operating the dynamo; if extra instruments are desired such as portable voltmeters, portable ammeters,