Зображення сторінки

power of the lamps; and that when two or
more are operating on the same circuit the
load may be divided between them in propor-
tion to their respective capacities under all
conditions from no load to full load ; if of the
alternate current, constant-current or con
stant-potential type, {they shall be guaran-
teed as efficient in


its ir operation as any of the direct-current types.

The dynamo(s) shall be rated with such margin of safety that ihey will not be injured if subjected to a temporary overload of

per cent. above such rating.

[ocr errors][merged small]

(See Note: p. 44., sec. 22.)

The foundation(s) for the(se) dynamo(s)
shall be built by the contractor

laid or of other material subject to the

contractor of

approval of the architect, and shall be of

sufficient length, width, and depth to safely
and firmly sustain

I their
Tits 5

weight. The
foundation(s) shall be capped with a framing
of well seasoned timber securely fastened
thereto, the dynamo base-frame(s) being se-
curely fastened to the framing or to the foun-
dation through the framing, both framing and
baseframe being secured in such a manner as
to prevent lateral motion in either direction

[ocr errors][ocr errors][ocr errors][ocr errors]

and to give an even bearing surface at every point. If metal is used to fasten framing or baseframe to the foundation it must be thoroughly insulated where it passes through them, and at all places liable to come in contact with the dynamo must be countersunk and covered with a moisture-proof insulating compound.

All necessary excavating and filling, and the removal of all débris shall be done hy the

{ contracter:} The height of the dynamo

. baseframe(s) above the ground will be

35. Iustri


(See Note: p. 45, sec. 23.)

There shall be provided with each dynamo one voltmeter or pressure indicator which shall remain constantly in circuit so as to indicate at all times the pressure at the point to which it is connected; 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; if of the constant potential type, one hand regulator made entirely of incombustible material, a headboard switch for cutting off the current at the dynamo, a compensator or suitable balancing device for keeping the current in each circuit practically constant; if of the constant current type an automatic regulator for so controlling the potential as lights are turned on or off that the current shall not vary appre

( Go

ciably from its normal value under any condition of load. There shall be provided for each circuit one ampère meter for indicating the current in said circuit, one ground detector which shall continuously indicate the insulation from the ground maintained at both poles and approximately the distance of any ground from the station, and one pair of efficient lighting arresters. There shall also be provided one testing magneto capable of ringing through — ohms.

36. Cables to


This contractor shall carry to the switchboard location at -- all regulator, exciter, auxiliary, 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. All wires shall be insulated with

- ;

shall be run of opposite polarity shall be separated at least --; and where crossing each other, wires of other circuits, or passing near metal pipes, girders, etc., shall be further protected by

In no case shall insulated wires be carried in such proximity to heated surfaces, vapors, or air as to endanger their insulation.

—; when


[blocks in formation]

39. Summary

[ocr errors]

(See Note: p. 47, sec. 27.)

Each bidder shall fill out completely the
following summary:
Number of dynamos
Trade number or designation
Rating in volts at maximum load
Rating in ampères át maximum load
Direct or alternating current .
Constant or varying current
Constant or varying potential
Series, shunt, compound, self or sepa-

rately excited
Rating of exciter in volts
Rating of exciter in ampères
Trade number or designation
Regulation by hand or automatic
Number of fully loaded circuits possi-

ble to operate per dynamo
Make of lamp recommended for use
Number of

C. p. lamps of above
make per circuit

c. p. lamp
Ampères per -- c. p. lamp
H. P. required to be delivered at the pul-

ley at full load with no loss in the
feeders but including exciter


Volts per

(See p. 48, sec. 28.)

40. Switch


There shall be placed upon this switch- 41. Switchboard, in addition to all the dynamo regula- atus and Conting 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. For systems operating dynamos and circuits in parallel, the appliances and connections shall be such as will permit adding to or taking from the circuit any dynamo without in any manner affecting the operation of the remaining dynamos in circuit or the candle power of the lamps, and will permit the cutting in or out of any circuit without affecting the stability of other circuits. For systems operating one dynamo for each circuit or series of circuits the connections shall be such as will permit any circuit to be connected to or disconnected from any dynamo with certainty and rapidity. (For switchboard connections see secs. 30 and 31, p. 50).

2. Circuits.

(See p. 51, sec. 32.)

Constant Potential, Alternating

Alternating Current System.

This contractor shall furnish, and, unless otherwise specified, erect the following apparatus and material:

43. Dynamo(s).

constant potential, alternating current dynamo(s) (each) having a capacity of · C. P.,

volt incandescent lamps.

« НазадПродовжити »