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size to accommodate all the regulating appara-
and set out not less than from
(Note.-This specification includes ouly the 29. Switch
board Appalo instruments used in the simplest of installations. The instruments required for any particular installation must, of course, be determined by its individual purposes and necessities.)
There shall be placed upon this switchboard
main ampère meters.
double-pole fusible cut-outs.
All switches carrying over ampères
and break contact automatically beyond the control of the operator, who shall simply set the switch at the point of making or breaking
Cut-outs shall be so protected that the molten metal cannot be spattered about on the fusing of the strip.
All switches and cut-outs shall be mounted on incombustible bases.
20. Connections ((oncealed).
All connecting wires shall be carried back of the switchboard using only insulated wire. All joints shall be soldered. All connections to switch t-outs, etc., shall be soldered or made wn approved form of lug or set screw, in all cases care being taken to secure good and sufficient contact to prevent heating and insure permanency; when made with lugs or set screws they shall be in plain sight and easily accessible for tightening. Connecting wires shall be so run and secured that crosses or grounds are impossible in the normal operation of the plant. All main wires shall have a capacity of at least í. M. per ampère, and no wire smaller than --- B. & S. or
B. W. G. shall be used.
31. Connections (sur
All dynamo, 'bus, feeder and riser wires shall be of
insulated wire fastened neatly
and securely to the front surface of the switchboard. All bare wires shall be separated from the board by an air space of not
less than Bus bars shall be of
- B. W. G. shall be used.
C. M. per
The following circuits will centre at the 32. Circuits. switchboard: (Enumeration of circuits
To different floors;
Power circuits, etc.
Incandescent Series System, Dynamos Medium
or High Potential (Variable or Constant),
This contractor shall furnish, and, unless otherwise specified, erect the following apparatus and material:
dynamo(s) (each) having a capacity of
c. p., incandescent lamps. The maximum voitage at the terminals of the dynamo(s) shall not exceed volts at full load.
The dynamo(s) shall be 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
I consecutive hours without increasing the temperature of any part, especially the arma
ture, fields, and commutator, to such a degree El Ciput, as to endanger the insulation or decrease the sempio dined efficiency of operation ; shall not spark unduly
with proper care of the commutator and ad-
tween all parts insulated from each other;
sed to working current
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 armaiure 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 of such design that the power required will be automatically proportioned to the number and candle-power of the lamps burning at any time; if of the direct and constant-current type it shall be so designed that with the proper connections two or more may be operated successfully in series, so that with ordinary care and precaution any dynamo may be added to or taken from the circuit without in any manner affecting the efficient operation of the remainder, and with but a momentary fluctuation in the candle power and steadiness of the lamps; if of the direct-current, constantpotential type they that with the proper connections two or more may be operated successfully in parallel so that with ordinary care and precaution any dynamo may be added to or taken from the circuit without in any manner affecting the operation of the remaining dynamos in circuit or causing any change in the candle
they shall be so designed