37. Starting Plant and Instruction. 38. Renewal Parts. sulated with shall be run ; when 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. (See p. 51, sec. 25.) (See p. 51, sec. 26.) 39. Summary. (See Note: p. 52, sec. 27.) Each bidder shall fill out completely the following summary: Rating in amperes Direct or alternating current Constant or varying current Constant or varying potential Series, shunt, compound, self or separately excited. Rating of exciter in volts Rating of exciter in amperes sible to operate per dynamo H. P. required to be delivered at the pulley at full load (See p. 53, sec. 28.) 40. Switchboard. board Apparatus and Connections. There shall be placed upon this switch- 41. Switchboard, in addition to all the dynamo regulating 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 42. Circuits. dynamo without in any manner affecting the operation of the dynamos remaining 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, pp. 55 and 56. (See p. 57, sec. 32.) Constant Potential, Alternating Current System. This contractor shall furnish, and, unless otherwise specified, erect the followling apparatus and material: (See Note: p. 43, sec. 21.) constant potential, alternating current dynamo(s) (each) having a capackilowatts. The maximum voltage at the terminals of the dynamo(s) shall not exceed ity of volts. 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 consecutive hours without increasing the temperature of any part, especially the armature, fields and commutator, to such a degree as to endanger the insulation or decrease the 43. Dynamo(8). efficiency of operation; 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 highspeed, automatic cut-off engines belted direct; shall be supplied 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; all contacts, brushes, binding posts, etc., shall be so placed and protected that there is the least possible danger of receiving a shock. The dynamo(s) shall be rated with such will not be margin of safety that they injured if subjected to an overload of per cent. above such rating for a period of ; if self-exciting the coils furnishing the exciting current, and the commutator shall be so insulated and protected |