phase windings; for single-phase service three-phase windings are used, the load being carried (at a reduced output) by any two leads of the threephase winding.

State whether this is to be driven by belt from generator shaft, by directconnection to generator shaft, or as a separately driven unit.

(9) Starting and Regulating Devices.

The field rheostat is usually furnished with the machine; the other material,
on large installations at least, had best be ordered separately. (See p. 113.)
(a) Direct Current Machines.

Field rheostat, circuit breaker, switch, voltmeter, ammeter, ground lamp,
and panel of switchboard to carry same.

If two or more generators are to operate in multiple, an equalizer will also be required.

(b) Alternating Current Machines.

Field rheostat, D.C. ammeter, D.C. voltmeter and field-discharge switch (all for exciter); ammeter, voltmeter, voltmeter receptacle, ammeter receptacle, main switch, ground-detector outfit, main fuses, and panel of switchboard to carry same.

If for parallel operation with other generators, a synchronizing outfit will also be required.

(10) Material to be Supplied. State which of the following items are to be supplied and also which are not to be supplied.

(a) Direct Current Generator.

Machine complete with pulley, base-plate with slide rails and tightener for floor/wall/ceiling mounting, field rheostat, switchboard and instruments (as listed, see "9-a" above), and spare parts (as listed).

(b) Alternating Current Generator.

Generator complete with pulley, base-plate with slide rails and tightener, driving pulley for exciter; belt driven/direct-connected exciter with tightening base, driven pulley and field rheostat; switchboard and instruments (as listed, see "9-b" above), and spare parts (as listed).

(11) Number of Units Required?

ELECTRIC MOTORS

Intended, primarily, for the inquirer who can state only the working conditions, leaving to the bidders the proposing of a suitable motor. The electrical engineer, however, will usually prefer to state definitely the type desired; see (7) below.

(1) For direct or alternating current service?

(2) Voltage? If A.C., state also phase and frequency.

(3) Horse-power to be developed, if known? If not known, amplify information called for by (4).

(4) Service.-Describe sufficiently, giving sizes or capacities of machines operated. State whether service is continuous or intermittent, constant or varying, and state the approximate percentage of overload and its duration. State whether open or enclosed type is required (a/c working conditions.)

(5) Speed.-State whether this is to be constant, e.g., line-shaft service; multispeed (two-speed, three-speed, etc.), e.g., fan service; adjustable-speed (variable over a considerable field, but when once adjusted of constant speed),

e.g., lathe service; or varying-speed (speed varying with load, decreasing with increased load, and vice versa), e.g., crane or street-car service. State the speed (or speeds) required if known; or, if not decided, give the R.P.M. of the shaft to be driven, etc., so that a motor of suitable speed may be proposed (in this case it is well to state a maximum allowable speed, as the price varies greatly with the speed.)

(6) Temperature Rise.-Specify any requirements, or ask bidder to state his guarantee.

(7) Type. If decided, state type of motor required as indicated by following list: (a) Direct Current Motors

Shunt-wound

Series-wound

Compound-wound.

Differentially-wound

(b) Alternating Current Motors

Synchronous

Induction

Squirrel-cage for constant speed
Squirrel-cage for variable speed
Phase-wound for constant speed

Phase-wound for variable speed

(8) Driving Connection. For each case, give information indicated.

(a) Pulley on armature shaft; give diameter and face if decided, or ask for standard or proposed size; state style of pulley desired, C.I., paper, etc. (b) Pulley on reduction shaft of back-geared motor; give information as for (a).

(c) Spur-gear pinion on armature-shaft, or on reduction-shaft; give pitchdiameter, face, number of teeth, style of teeth; or give same information for driven gear or chain and ask for suitable pinion; state style of pinion desired, C.I. steel, rawhide, etc.

(d) Coupling on armature-shaft, or on reduction-shaft for direct-connection to pump, line-shaft, etc. If coupling is to be furnished by motor contractor, indicate type desired (flange, flexible, etc.), and give exact (not nominal) diameter of driven shaft.

(9) Mounting.-State whether motor is to be mounted on:

(a) Foundation direct without use of C.I. base, requiring only foundationbolts.

(b) Common base-plate of direct-connected pump, etc., requiring dowels and bolts.

(c) C.I. base with rails and tightening screws, requiring also foundation bolts. State whether for floor, wall or ceiling mounting.

(10) Starting and Regulating Devices.-Every motor of any size must be provided with some sort of rheostat, compensator or controller for starting and regulating, and this should, preferably, be ordered as part of the equipment. Switches and fuses may also be called for, the whole mounted on a suitable board. (11) Miscellaneous.-Gear-case for back-geared motor.

other instruments for starting board.

Wiring, etc., for distant control.

Belt-tightener attachment.

Volt-meter, ammeter, or

(12) Material to be Supplied.-State which of the following indicated items are to be supplied, and also which are not to be supplied.

Motor as described above complete with, (a) pulley, gear, etc., as per (8)

above; (b) base-plate, etc., as per (9) above; (c) rheostat, switch, etc., as per (10) above; (d) miscellaneous attachments as per (11) above; (e) spare parts. (13) Number of Units Required?

CONSTANT-POTENTIAL STATIC TRANSFORMERS FOR LIGHTING OR
POWER

(1) Number of transformers required?

Note that for three-phase work, three single-phase or one three-phase transformer may be used per circuit, depending on circumstances.

For three-phase transformer state whether "Star" or "Delta" connection is to be used.

(2) Capacity in K.W., allowing for power-factor of load?

(3) Method of cooling? Oil-cooled and air-cooled in small sizes; air-blast and water-cooled in large sizes.

(4) Step-up or step-down? State primary and secondary voltages wanted. (5) Frequency?

(6) Describe service.

(7) Bidders to state temperature rise, efficiency and regulation of their transformers.

(8) Primary cut-outs, hangers (for small sizes), and oil to be included in price.

SMALL CENTRIFUGAL PUMPS

Note. For outline of specification for larger (special) units, see p. 115. (1) Number of pumps required.

(2) Capacity of each in U. S. gallons per minute.

(3) Normal and maximum suction lift (vertical, to floor), length, size and kind of suction pipe.

(4) Discharge head (vertical, from floor), length, size and kind of discharge pipe. (5) Friction Heads.-Give an assumed friction head; or, if there are any bends or obstructions in the pipe line, describe same so that friction head may be estimated.

(6) Variation in lift, both suction and discharge, if any.

(7) Quality of liquid; fresh water, gritty, acidulous, solids in suspension, etc. (8) Temperature of liquid (deg. Fah.).

(9) Specific gravity of liquid.

(10) Service; describe briefly, stating whether continuous or intermittent, etc.
(11) Drive.-State kind of drive, giving the information indicated under the proper
(or relative) heading below.

(a) Belted.-Give R.P.M. of shaft, and the maximum diameter of driving
pulley desirable, or the diameter of existing (engine or motor) pulley.
(b) Direct-connection to electric motor. For direct current, give voltage;
for alternating current, give voltage, frequency and phase.

(c) Direct-connection to steam engine or steam turbine. Give steam pres-
sure and state whether operating condensing, non-condensing or against in
back-pressure.

(12) Type of pump preferred. State any special requirements; such as special material (other than C.I.) for casing, for impeller, etc.; single or double suction; position of suction and discharge; maximum R.P.M. allowed. (13) Will motive power be furnished by the pump manufacturer or by others? If by others, is pump to be built right- or left-hand? (See diagram.)

Note.

If motor is not to be fitted to pump, pin gauges and keyway gauges

should be exchanged.

(16) "Position" of pump. Indicate by sketch, taken from diagram above, the

the pump contractor? Which contractor furnishes coupling? (15) If motive power is furnished by others, is the motor to be fitted to the pump by (14) Is pump contractor to furnish sub-base to take both pump and motive power?

FIG. 26. "Hand" and "position" of centrifugal pumps, looking from suction side (for a single-suction pump), or
from side opposite to driving pulley or coupling (for a double-suction pump). Note 1. Makers differ as to direc-
tion of "hand," that shown above ("right" hand for direction of hands of a watch and vice versa) is most com-
mon; always send sketch. Note 2. For double-suction pumps, suction at 45° down is impossible, as it interferes with
the base.

required position of suction and discharge openings, and the required direction of rotation.

(17) Miscellaneous.-Is a (steam or water) ejector required for priming? Are any foot, gate, check or other valves required with pump? Are any spare parts to be furnished? Are foundation-bolts to be supplied?

POWER PUMPS (TRIPLEX, ETC.)

(1) Service. For what use is pump intended?

(2) Capacity: number of U. S. Gallons per minute, average and maximum? (3) Liquid: fresh water or other liquid, salt, gritty, acidulous, temperature (deg. Fah.), etc.? If other than fresh water, give the specific gravity.

(4) Suction head: vertical distance from water-level to floor line; size, length and material of pipe line?

(5) Discharge head: vertical distance from floor line to level of discharge; size, length and material of pipe line? Or give pressure (in pounds per square inch) against which pump will discharge.

(6) Friction head: give an assumed figure, or describe any bends or obstructions in the pipe line so that friction may be figured.

(7) If for Belted or Rope drive: give R.P.M. of driving shaft, and maximum or desired diameter of pulley; or, for Engine or Motor drive, give R.P.M. and diameter of driving wheel or pulley if known.

(8) If for Geared Connection to Motor: give kind of current and voltage, and, if alternating, give also frequency and phase. If motor is selected, give its H.P., R.P.M., make and class (or send sketch).

(9) If for Geared Connection to (Steam) Engine: state steam pressure and whether operating condensing, non-condensing or against back-pressure. If engine is selected, state its (cylinder) size, R.P.M., make and class (or send sketch). (10) Is the pump contractor to furnish the motive power? If not, make arrangements for interchange of sketches and templets, and state who furnishes the gearing, etc., and state whether motive power is to be shipped to the pump so the whole may be fitted in the shop.

(11) Are any spare valves, seats and springs, or other spare parts to be furnished?

DEEP WELL PUMPS

(1) For what purpose is the pump to be used?

(2) What is the maximum and the average U.S.Gallons per minute required to be pumped.

(3) Is the water clear or gritty?

(4) Is well cased with Standard Wrought Pipe or Artesian Well casing?

(5) Inside diameter of well casing?

(6) Depth of well?

(7) Depth of well casing? If water is found in sand, is strainer properly set? (8) Depth to surface of water?

(9) If surface discharge or suction pipes are now in position, give diameter and length, and state number of turns and valves in each.

(10) Give vertical distance to which water must be forced, or against what pressure. (11) Give power available to run pump, or, if none is on hand, state style of power preferred.

(12) State style of pump preferred.