Usage:
English Units
Air Compressors:
BHP = 1/4 × cu. ft. per minute at 100 psi
Increase BHP 10% for 125 psi
Decrease BHP 10% for 80 psi
AMA HP for U.S.A. Tax Purposes:
Where: N = No. of Cylinders
D = Piston Diameter in inches
Brake Mean Effective Pressure:
Conveyors: 15 to 20° incline.
Cooling:
Heat Exchanger Flow Rate
Raw water to jacket water 1:1 to 2:1
Submerged Pipe Cooling
1/2 Sq. ft. surface area per HP
With 85°F flowing raw water
Electricity:
Generator Capacity Required:
Motors:
1 kW per nameplate HP (motor running cool or warm to touch)
11/4 kW per nameplate HP (motor running hot to touch)
Horsepower Requirements:
11/2 BHP per kW of load or
Electric Sets:
Motor Starting Requirements:
Inrush kVa (Code F motor) = 5.5 × BHP
Inrush Current (Code F motor)= 6.2 × Full load rated current
1 kVa per HP at full load
Generator full load rated current capacity:
Generator Cooling Requirements:
Air Flow - 150°CFM per kW loss × efficiency
Circuit Breaker Trip Selection:
1.15 to 1.25 × full load generator amp rating
Single Phase Rating of 3-Phase Generator:
60% of 3-phase rating
Generator Temperature Rise:
Increase 1°C for each 330 feet above 3300 feet
Fuel Consumption
Gas Compressor:
BHP = 22 RcVS
Where: Rc = Stage Compression Ratio
V = Million cu. ft./day
S = Number of Stages
Heat Rejection
% of Fuel Energy Consumed
Jacket Water
Prechambered engines
Direct injection engines
Hours Per:
Year = 8760 (365 Days)
Week = 168 (7 Days)
Month = 720 (30 Days)
Oilfield Drilling:
Hoisting
Mud Pumps
Rotary Table
On Site Power Requirements:
Based on 100,000 sq. ft. of office bldg., etc., and 40°N. latitudes
Electric Requirements:
Air Conditioning Compressor
Pumps:
Pipe Line BHP = Barrels per hour × psi × 0.00053
*Efficiency
Refrigeration
One ton refrigeration = 200 BTU/Min. = 12,000 BTU/Hr.
One boiler HP = 33,475 BTU/Hr.
One ton compressor rating = One Engine HP
Auxiliary air conditioning equipment requires 1/4 HP per ton of compressor rating
Ice Plant:
Complete power requires 4-5 HP per daily ton capacity
Sawmill:
11/2 BHP per inch of saw diameter at 500 RPM
Increase or decrease in proportion to RPM
Swing Cut-Off Saw
Table Trimmer 71/2 to 10 BHP
Blower Fan 12-foot sawdust 3 to 5 BHP
Planer Mill 2 to 4 BHP per 100 board feet per hour 24 to 30-inch planers 15 to 25 BHP
Edgers
Approximate fuel consumption:
Softwood 1 gal. per 1000 board feet
Hardwood 1 gal. per 750 board feet
Propellor Shaft Size Selection:
For intermediate shaft and tailshaft in marine installations
Where: D = Diameter in inches
HP = Horsepower
S = Torsional stress in PSI (usually 5000)
Shovels and Draglines:
Use manufacturer's recommendations.
Torque: (4 cycle only)
Torque Converters:
Peak output shaft horsepower:
Normally 80% of input horsepower for either single or three-stage converter
Output shaft speed at peak output horsepower:
Single-stage - 0.7 to 0.85 engine full load speed
Three-stage - 0.5 to 0.6 engine full load speed
Torque multiplication at or near stall:
Single-stage - 2.2 to 3.4 times engine torque
Three-stage - 3.6 to 5.4 times engine torque
Ventilation:
Natural 1/2 net square inch for each BHP
Blown 1/3 net square inch for each BHP
Metric Units
Air Compressors:
110 kW = 1 m3/min @ 850 kPa
100 kW = 1 m3/min @ 675 kPa
90 kW = 1 m3/min @ 550 kPa
AMA Power for U.S.A. Tax Purposes:
Where: N = No. of Cylinders
D = Piston Diameter in millimeters
Brake Mean Effective Pressure:
Conveyors: 15 to 20° incline.
Cooling:
Heat Exchanger Flow Rate
Raw water to jacket water 1:1 to 2:1
Submerged Pipe Cooling
1 m2 surface area per 16 kW with 30°C flowing raw water
Electricity:
Generator Capacity Required:
Motors:
11/3 kW per nameplate kW (motor running cool or warm to touch)
12/3 kW per nameplate kW (motor running hot to touch)
Engine Power Requirements:
Electric Sets:
Motor Starting Requirements:
Inrush kVa (Code F motor) = 41/8 × nameplate kW
Inrush Current (Code F motor) = 6.2 × full load rated current
11/3 kVa per kW at full load
Generator full load rated current capacity:
Generator Cooling Requirements:
Air Flow = 41/4 m3 per kW loss × efficiency
Circuit Breaker Trip Selection:
1.15 to 1.25 × full load generator amp rating
Single Phase Rating of 3-Phase Generator:
60% of 3-Phase rating
Generator Temperature Rise:
Increase 1°C for each 100 meters above 1000 meters
Fuel Consumption
3
*33 720 kJ/m
Gas Compressor:
kW = 777 Rc VS
Where : Rc = Stage Compression Ratio
V = Millions cubic meters per day
S = Number of Stages
Heat Rejection:
Hours Per:
Year = 8760 (365 Days)
Week = 168 (7 Days)
Month = 720 (30 Days)
Oilfield Drilling:
Mud Pumps
Rotary Table
On Site Power Requirements:
Based on 10 000 m2 of office bldg., etc. and 40°N latitude.
Electric Requirements:
Air Conditioning Compressor:
Pumps:
Deep Well kW = (meters of lift × L/min × 4640)
Pipe Line kW = L/H × kPa × 2 775 000
*Efficiency
Refrigeration:
One ton refrigeration = 3.5 kW
One boiler hp = 9.8 kW
One ton compressor rating = 0.75 kW
Auxiliary air conditioning equipment requires 1/5 kW per ton of compressor rating
Ice Plant:
Complete power requires 3.25-4.25 kW per daily ton capacity
Sawmill:
1 kW per 20 to 25 mm saw diameter at 500 RPM
Increase or decrease in proportion to RPM
Swing Cut-Off Saw
Table Trimmer 51/2 to 71/2 kW
Blower Fan 4 meter sawdust 21/4 to 33/4 kW
Planer Mill 5-10 kW m3 per hour 600-750 mm planers 11 to 19 kW
Edgers
2 saws 9 to 11 kW
3 saws 11 to 19 kW
Slab saw 7.5 kW
Jack Ladder 7.5 kW
Approximate fuel consumption:
Shaft Size Selection:
For intermediate shaft and tailshaft in marine installations
Where: D = Diameter in millimeters
kW = Power in kilowatts
S = Torsional stress in MPa (usually 35)
Shovels and Draglines:
Use manufacturer's recommendations.
Torque: (4-cycle only)
Torque Converters:
Peak output shaft kilowatts:
Normally 80% of input power for either single or three stage converter
Output shaft speed at peak output kilowatts:
Single-stage - 0.7 to 0.85 engine full load speed
Three-stage - 0.5 to 0.6 engine full load speed
Torque multiplication at or near stall:
Single-stage - 2.2 to 3.4 times engine torque
Three-stage - 3.6 to 5.4 times engine torque
Ventilation:
Natural 41/2 cm2/kW
Blown 3 cm2/kW
English to Metric Conversion Factor
Energy
Power
Length
Volume and Capacity
Weight
Angle
Pressure and Head
Flow
Area
Temperature Conversion
