Introduction
Selecting service factors for drive systems is a very imprecise science
and it is recommended that the engineer use the information provided by
the drive system supplier for detailed design work. The table
below is provided to indicate in general, the level of service factor to
apply for drive systems based on some knowledge of the driver equipment, the
driven equipment and the operating period.
Some judgment is required in applying service factors for it is clear
that a well designed drive includes provisions i.e flywheels, slipping clutches,
fluid couplings etc which will effectively isolate the loads providing
relatively smooth drive conditions even with load which have high levels
of shock loading.
Service Factors Synchronous Drives
Driven
Equipment;
|
v |
Operating Period /day |
| < 8 h |
< 16 h |
> 16 h |
< 8 h |
< 16 h |
> 16 h |
< 8 h |
< 16 h |
>16 h |
Driving Machine:Smooth
Starting torque 100% - 150% FL |
Driving :Moderate Vibration
Starting torque 150% - 250% FL |
Driving Machine:Heavy Vibration
Starting torque 250% - 400% FL |
Electic Motors -Star Delta
DC motors-shunt wound
IC engines over 8 cyl'rs
Water Turbines
Steam Turbines |
AC motors starting torque
IC engines with 4-6 cylinders |
AC Motors (DOL)
Two stroke Engines
IC engines under 600 rpm, |
Instrumentation
Office display equipment
Medical Equipment |
1 |
1.2 |
1.4 |
1.1 |
1.3 |
1.5 |
1.2 |
1.4 |
1.6 |
Domestic Appliances
Oven Screens
Woodworking Drills
Woodworking Drills Lathes |
1.1 |
1.3 |
1.5 |
1.2 |
1.4 |
1.6 |
1.3 |
1.5 |
1.7 |
Liquid agitators,
Heavy Woodworking Tools
Belt conveyors
|
1.2 |
1.4 |
1.6 |
1.4 |
1.6 |
1.8 |
1.6 |
1.8 |
2 |
Sludge Agitators,
Conveyors,
Milling Machines
Shaper Machines
Grinding Machines |
1.3 |
1.5 |
1.7 |
1,5 |
1,7 |
1,9 |
1.6 |
1.8 |
2 |
Brick Machinery
Rubber Calendar Mills
Rubber Extruders
Centrifugal Blowers
Elevators |
1.4 |
1.6 |
1.8 |
1.6 |
1.8 |
2 |
1.8 |
2 |
2.2 |
| Centrifugers, Paper Pulpers, Hammer Mills, |
1.5 |
1.7 |
1.9 |
1.7 |
1.9 |
2.1 |
1.9 |
2.1 |
2.3 |
Blowers-positive displacment
Pulverisers.
Mine Fans |
1.6 |
1.8 |
2 |
1.8 |
2 |
2.2 |
2 |
2.2 |
2.4 |
Reciprocating Compressors
Crushers
Steelmaking machines
Reciprocating pumps
|
1.7 |
1.9 |
2.1 |
1.9 |
2.1 |
2.3 |
2.1 |
2.3 |
2.5 |
Service Factors Vee ( V ) Belts
Driven
Equipment;
|
v |
Operating Period /day |
| < 8 h |
< 16 h |
> 16 h |
< 8 h |
< 16 h |
>16 h |
Driving Machine:
Reasonable Smooth
Starting torque 100% - 200% FL |
Driving Machine:
Coarse
Starting torque 200%-400% |
Electic Motors -Star Delta
DC motors-shunt wound
IC engines over 8 cyl'rs
Turbines
|
DC Motors with series/mixed excitation
AC Motors (DOL)
Two stroke Engines
IC engines under 600 rpm, |
Smooth Machine Tools-Lathes drills etc
Liquid agitators,
Blowers, Exhausters
Light Duty conveyors
Centrifugal Pumps
|
1,0 |
1,1 |
1,2 |
1,1 |
1,2 |
1,3 |
Uneven Machine Tools-Milling /Gearcutting;etc
Printing machines
Laundry Machinery
Generators
Piston pumps and compressors(4+ cylinder)
Fans and blowers
Chain conveyors
Elevators
Circular saws for wood
Transmissions
Printing ,Paper-making machines
Food-industry machines-dough mixers
Heavy screens
Rotary furnaces
High-speed grinders
Positive Displacement Rotary Pumps
Revolving Vibrating screens
Punches/Presses |
1,1 |
1,2 |
1,3 |
1,2 |
1,3 |
1,4 |
Planing machines
Vertical shapers and wood-processing machines
Piston pumps and compressors with one or two cylinders
Bucket elevators
Fans and blowers of heavy types
Exciters
Screw and drag conveyors
Crushers
Piston Pumps
Presses heavy flywheels
Weaving machines
Machines for cleaning cotton
Machines for pressing and pelletising fodder
Positive Displacement Blowers
|
1,2 |
1,3 |
1,4 |
1,3 |
1,4 |
1,6 |
Hoists
Excavators
dredgers
Heavy presses
shears
Mechanical hammers
Mills(ball, rod, tube)
Stone crushers
Hammer mills
Crushers (gyratory, jaw, roll)
Sawmill machines
Rubber Calendars, extruders, Mills |
1,3 |
1,4 |
1,5 |
1,5 |
1,6 |
1,8 |
|