Page 323 - Machinery Component Maintenance

Table 6-5
Balance Quality Grades for Various Groups of Representative Rigid Rotors
in Accordance with IS0 1940 and ANSI S2.19-1975
Balance
Quality
Grade G Rotor Types-General Examples
G 4000 Crankshaft-drives (2) of rigidly mounted slow marine diesel engines with
uneven number of cylinders (3).
G 1600 Crankshaft-drives of rigidly mounted large two-cycle engines.
G 630 Crankshaft-drives of rigidly mounted large four-cycle engines. Crankshaft-
drives of elastically mounted marine diesel engines.
G 250 Crankshaft-drives of rigidly mounted fast four-cylinder diesel engines (3).
G 100 Crankshaft-drives of fast diesel engines with six and more cylinders (3).
Complete engines (gasoline or diesel) for cars, trucks and locomotives (4).
G 40 Car wheel (5), wheel rims, wheel sets, drive shafts. Crankshaft-drives of
elastically mounted fast four-cycle engines (gasoline or diesel) with six and
more cylinders (3). Crankshaft-drives for engines of cars, trucks and loco-
motives.
G 16 Drive shafts (propeller shafts, cardan shafts) with special requirements.
Parts of crushing machinery. Parts of agricultural machinery. Individual
components of engines (gasoline or diesel) for cars, trucks and locomotives.
Crank-shaft-drives of engines with six or more cylinders under special re-
quirements.
G 6.3 Parts of process plant machines. Marine main turbine gears (merchant ser-
vice). Centrifuge drums. Fans. Assembled aircraft gas turbine rotors. Fly-
wheels. Pump impellers. Machine-tool and general machinery parts. Me-
dium and large electric armatures (of electric motors having at least 80 mm
shaft height) without special requirements. Small electric armatures, often
mass produced, in vibration insensitive applications and/or with vibration
damping mountings. Individual components of engines under special re-
quirements.
G 2.5 Gas and steam turbines, including marine main turbines (merchant service).
Rigid turbogenerator rotors. Rotors. Turbo-compressors. Machine-tool
drives. Medium and large electrical armatures with special requirements.
Small electric armatures not qualifying for one or both of the conditions
stated in G6.3 for such. 'hrbine-driven pumps.
GI Tape recorder and phonograph drives. Grinding-machine drives. Small elec-
trical armatures with special requirements.
G 0.4 Spindles, discs, and armatures of precision grinders. Gyroscopes.
NOTES:
1. The quality grade number represents the maximum permissible circular velocity of
the center of gravity in mm/sec.
2: A crankshaft drive is an assembly which includes the crankshaft, a flywheel, clutch,
pulley, vibration damper, rotating portion of connecting rod, etc.
3. For the purposes of this recommendation, slow diesel engines are those with a piston
velocity of less than 30 ft. per sec., fast diesel engines are those with a piston veloc-
ity of greater than 30 ft per sec.
4. In complete engines, the rotor mass comprises the sum of all masses belonging to
the crankshaft-drive.
5. G 16 is advisable for off-the-car balancing due to clearance or runout in central
pilots or bolt hole circles.