REQUIRED
LIFE AT CONSTANT OPERATING SPEED
( data from SKF Industries) |
Type of machine |
Life
in hours
of operation |
|
Instruments and
apparatus which are only infrequently used
Ex.: demonstration apparatus, devices for operation of sliding doors.... |
500 |
|
Aircraft
engines ............................................................................... |
500—2000 |
|
Machines
for service of short duration or intermittent operation, where service interruptions are
of minor importance
Ex: hand tools, lifting tackle In machinery shops, hand-driven machines in general, farm
machinery, assembly cranes, charging machines, foun dry cranes, household machines
......................... |
4000—8000 |
|
Machines
for intermittent service where dependable operation is of great importance
Ex: auxiliary machines in power stations, conveying-equipment in
production lines, elevators, general-cargo cranes, machine tools less frequently
used ........... |
8000—12,000 |
|
Machines
for 8—hour service which are not always fully utilized
Ex: machines in general in the mechanical industries, cranes for
continuous service, blowers, jackshafts..................................... |
20,000—30,000
|
|
Machines
for continuous operation (24—hour service)
Ex.: separators, compressors, pumps, main-line shafting, roller beds and conveyor rollers,
mine hoists, stationary electric motors ................................ |
40,000—60,000 |
|
Machines
for 24—hour service where dependability is of great importance Ex.: pulp and paper
machines, public power stations, mine pumps, public pumping stations, machines for
continuous service aboard ship ............................. |
100,000—200,000
|
|
