SERVICE FACTORS & SERVICE-RATING :

The service rating of a Gearboxe represents its capacity to meet the specific requirements of the actual applications, considering the operating conditions the desired service life and reliability. At the first estimate service rating multiplied by an appropriate service factor shall not exceed the catalogue rating. This factor measures the intangibles such as load variations, shock and overloading, Reliability and Life. The service factors listed in Table 1 are based on the experience of gear manufacturers and users over the past several years. They have served the industry well, and can be used with a good deal of confidence if the application has been idetified by knowledgeble and experienced gear design and application engineers. It may be noted that the tabulated values apply only to a speed reducing gear box, with a uniform torque input as is the case when driven by electric or oil hydraulic motors or steam or gas turbines.

For speed increasing applications or when the input torque varies cyclically (i, e, engine drive), please refer back to us.

SERVICE FACTORS FOR ENCLOSED GEAR DRIVES, DRIVEN BY MOTORS (HYDRAULIC & ELECTRIC) AND TURBINES (STEAM OR GAS)

Application

 Load duration/day  

Application

 Load duration/day

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs
AGITATORS (Mixers) * CRANES – Dry Dock
Pure Liquids 1.00 1.00 1.25 Main Hoist 2.50 2.50 2.50
Liquids and Solids 1.00 1.25 1.50 Auxiliary Hoist 2.50 2.50 3.00
Liquids – Variable density 1.00 1.25 1.50 Boom Hoist 2.50 2.50 3.00
BLOWERS Slewing Drive 2.50 2.50 3.00
Centrifugal 1.00 1.00 1.25 Traction Drive 3.00 3.00 3.00
Lobe 1.00 1.25 1.50 CRANES – Container
Vane 1.00 1.25 1.50 Main Hoist 3.00 3.00 3.00
BREWING AND DISTILLING Boom Hoist 2.00 2.00 2.00
Bottling Machinery 1.00 1.00 1.25 Trolley – Gantry Drive 3.00 3.00 3.00
Brew Kettles-Cont. duty 1.25 1.25 1.25 Trolley – Traction Drive 2.00 2.00 2.00
Cookers – Cont. duty 1.25 1.25 1.25 CRANES - Mill Duty
Mash tubes 1.25 1.25 1.25 Main Hoist 3.50 3.50 3.50
Scale Hopper-Frequent Starts 1.25 1.25 1.5025 Auxiliary 3.50 3.50 3.50
CAN FILLING MACHINES 1.00 1.00 1.25 Bridge & Trolley Travel 2.50 3.00 3.00
CAR DUMBERS 1.50 1.75 2.00 CRANES – Industrial Duty
CAR PULLERS 1.00 1.25 1.50 Main 2.50 2.50 3.00
CLARIFIERS 1.00 1.00 1.25 Auxiliary 2.50 2.50 3.00
CLASSIFIERS 1.00 1.25 1.50 Bridge & Trolley Travel 2.50 3.00 3.00
CLAY WORKING MACHINERY CRUSHER
Brick Press 1.50 1.75 2.00 Stone or ore 1.75 1.75 2.00
Briquette Machine 1.50 1.75 2.0 DREDGES
Pug Mill 1.00 1.25 1.50 Cable Reels 1.25 1.25 1.50
COMPACTORS 2.00 2.00 2.00 Conveyors 1.25 1.25 1.50
COMPRESSORS Cutter Head Drives 2.00 2.00 2.00
Centrifugal 1.00 1.00 1.25 Pumps 2.00 2.00 2.00
Lobe 1.00 1.25 1.50 Screen drives 1.75 1.75 2.00
Reciprocating -Multi Cylinder 1.5 1.5 1.75 Stackers 1.25 1.25 1.50
Reciprocating-Single cylinder 1.75 1.75 2.00 Winches 1.25 1.25 1.50
CONVEYORS-GENERAL PURPOSE ELEVATORS
Uniform loaded- Heavy duty 1.00 1.00 1.25 Bucket 1.00 1.25 1.50
Not Uniformly fed 1.00 1.25 1.50 Centrifuge Discharge 1.00 1.00 1.25
Reciprocating or shaker 1.50 1.75 2.00 Escalators 1.00 1.00 1.25

* Crane Drives are to be selected based on gear tooth bending strength. Contact manufacturer for strength ratings. Service factor in durability should be a minimum of 1.0

Note: Service factor shown for cranes are based on tooth bending strength and their use must be Coordinated with the manufacturer. The values shown are consistent with those Recommended by C.M.A.A (Crane Manufacturers Association of America)


SERVICE FACTORS FOR ENCLOSED GEAR DRIVES, DRIVEN BY MOTORS (HYDRAULIC & ELECTRIC) AND TURBINES (STEAM OR GAS)

Application

 Load duration/day  

Application

 Load duration/day

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs
ELEVATORS – Contd.. LAUNDRY
Freight 1.00 1.25 1.50 Thumblers 1.25 1.25 1.50
Gravity discharge 1.00 1.00 1.25 Washers 1.50 1.50 2.00
EXTRUDERS LUMBER INDUSTRY
General 1.50 1.50 1.50 Barkers-Spindle Feed 1.25 1.25 1.50
Plastics-Variable speed drive 1.50 1.50 1.50 Main Drive 1.75 1.75 1.75
Plastics-Fixed speed drive 1.75 1.75 1.75 Conveyors-Burner 1.25 1.25 1.50
Rubber-Cont.Screw operation 1.75 1.75 1.75 Main or heavy duty 1.50 1.50 1.50
Rubber –Intermittent Screw Main Log 1.75 1.75 2.00
Operation 1.75 1.75 1.75 Re-saw,Merry-Go-round 1.25 1.25 1.50
FANS Conveyors-Slab 1.75 1.75 2.00
Centrifugal 1.00 1.00 1.25 Conveyors-Trasfer 1.25 1.25 1.50
Cooling towers 2.00 2.00 2.00 Chains – Floor 1.50 1.50 1.50
Forced Draft 1.25 1.25 1.25 Chains – Green 1.50 1.50 1.75
Induced Draft 1.50 1.50 1.50 Cut-Off Saws-Chain 1.50 1.50 1.75
Industrial & Mine 1.50 1.50 1.50 Cut-Off Saws-Drag 1.50 1.50 1.75
FEEDERS Debarking Drums 1.75 1.75 2.00
Apron 1.00 1.25 1.50 Feeds-Edger 1.25 1.25 1.50
Belt 1.00 1.15 1.50 Feeds-Gang 1.75 1.75 1.75
Disc 1.00 1.00 1.25 Feeds-Trimmer 1.25 1.25 1.50
Reciprocating 1.50 1.75 2.00 Log Deck 1.75 1.75 1.75
Screw 1.00 1.25 1.50 Log Hauls-Incline-l
FOOD INDUSTRY Well type 1.75 1.75 1.75
Cereal Cooker 1.00 1.00 1.25 Log turning devices 1.75 1.75 1.75
Dough Mixer 1.25 1.25 1.50 Planet Feed 1.25 1.25 1.25
Meat Grinders 1.25 1.25 1.50 Planer Tilting Hoists 1.50 1.50 1.50
Slicers 1.25 1.25 1.50 Rolls-Live-off brg-roll
GENERATORS & 1.00 1.00 1.25 Cases 1.75 1.75 1.75
EXCITERS Sorting Table 1.25 1.25 1.50
HAMMER MILLS 1.75 1.75 2.00 Tipple Hoist 1.25 1.25 1.50
HOISTS Transfers-Chain 1.50 1.50 1.75
Heavy duty 1.75 1.75 2.00 Transfers-Craneway 1.50 1.50 1.75
Medium Duty 1.25 1.25 1.50 Tray Drivers 1.25 1.25 1.50
Skip Hoist 1.25 1.25 1.50 Veneer Lathe Drives 1.25 1.25 1.50


SERVICE FACTORS FOR ENCLOSED GEAR DRIVES, DRIVEN BY MOTORS (HYDRAULIC & ELECTRIC) AND TURBINES (STEAM OR GAS)

Application

 Load duration/day  

Application

 Load duration/day

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs
METAL MILLS PAPER MILLS (Cont.)
Draw Bench Carriage and 1.25 1.25 1.50 Beater 1.50 1.50 1.50
Main Drive Breaker Stack 1.25 1.25 1.25
Runout Table-Non reversing # Calender 1.25 1.25 1.25
Group Drives 1.50 1.50 1.50 Chipper 2.00 2.00 2.00
Individual drives 2.00 2.00 2.00 Chip Feeder 1.50 1.50 1.50
Runout Table - Reversing 2.00 2.00 2.00 Coating Rolls 1.25 1.25 1.25
Slab Pushers 1.50 1.50 1.50 Conveyors
Shears 2.00 2.00 2.00 Chip,Bark,chemical 1.25 1.25 1.25
Wire Drawing 1.25 1.25 1.50 Log (Including Slab) 2.00 2.00 2.00
Wire Winding Machine 1.25 1.50 1.50 Couch rolls 1.25 1.25 1.25
METAL STRIP PROCESSING MACHINERY Cutter 2.00 2.00 2.00
Bridlers 1.25 1.25 1.50 Cylinder Molds 1.25 1.25 1.25
Coilers & Uncoilers 1.00 1.00 1.25 # Dryers-Paper Machine 1.25 1.25 1.25
Edge Trimmers 1.00 1.25 1.25 # Dryers-Conveyor Type 1.25 1.25 1.25
Flatteners 1.25 1.25 1.50 Embosser 1.25 1.25 1.25
Loopers (Accumulators) 1.00 1.00 1.25 Extruder 1.50 1.50 1.50
Pinch Rolls 1.25 1.25 1.50 Fourdrinier Rolls (Includes Lump
Scrap Choppers 1.25 1.25 1.50 Breaker, dandy roll, wire turning and
Shears 2.00 2.00 2.00 Return rolls 1.25 1.25 1.25
Slitters 1.00 1.25 1.50 Jordan 1.50 1.50 1.50
MILLS ROTORY TYPE Kiln Drive 1.50 1.50 1.50
Ball and Rod Mt. Hope roll 1.25 1.25 1.25
Spur ring Gear 2.00 2.00 2.00 Paper Rolls 1.25 1.25 1.25
Helical Ring gear 1.50 1.50 1.50 Platter 1.50 1.50 1.50
Direct connected 2.00 2.00 2.00 Presses-Felt & Suction 1.25 1.25 1.25
Cement Kilns 1.50 1.50 1.50 Pulper 2.00 2.00 2.00
Dryers and Coolers 1.50 1.50 1.50 Pumps-Vacuum 1.50 1.50 1.50
MIXERS - Concrete 1.25 1.25 1.50 Reel (surface Type) 1.25 1.25 1.25
* PAPER MILLS Screens-Chip 1.50 1.50 1.50
Agitator (Mixer) 1.50 1.50 1.50 Screens-Rotary 1.50 1.50 1.50
Agitator for pure Liquors 1.25 1.25 1.25 Screens-vibrating 2.00 2.00 2.00
Barking Drums 2.00 2.00 2.00 Size Press 1.25 1.25 1.25
Barkers-Mechanical 2.00 2.00 2.00 Thickner (DC Motor) 1.25 1.25 1.25
Thickner (AC Motor) 1.50 1.50 1.50

 

* Service factors for paper mill applications are applied to the name plate rating of the electric drive motor at the motor rated based speed

# Anti-Friction Bearings only. Use 1.5 for sleeve bearings.


SERVICE FACTORS FOR ENCLOSED GEAR DRIVES, DRIVEN BY MOTORS (HYDRAULIC & ELECTRIC) AND TURBINES (STEAM OR GAS)

Application

 Load duration/day  

Application

 Load duration/day

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs
PAPER MILLS (Cont.) PUMPS (Cont.)
** Super Calender 1.25 1.25 1.25 Rotary – Gear type 1.00 1.00 1.25
Washer (AC Motor) 1.50 1.50 1.50 Rotary - Lobe 1.00 1.00 1.25
Washer (DC Motor) 1.25 1.25 1.25 Rotary – Vane 1.00 1.00 1.25
Wind & Unwind stand 1.00 1.00 1.25 RUBBER INDUSTRY
Winders (Surface Type) 1.25 1.25 1.25 Intensive Internal Mixers
# Yankee Dryers 1.25 1.25 1.25 Batch Mixers 1.75 1.75 1.75
PLASTIC INDUSTRY (Primary Processing) Continuous Mixers 1.50 1.50 1.50
Intensive Internal Mixers Mixing Mill –
Batch Mixers 1.75 1.75 1.75 2 Smooth Rolls 1.50 1.50 1.50
Continuous Mixers 1.50 1.50 1.50 (If Corrugated Rolls are used then use the
Batch Drop Mills Same service factor that are used for a
(2 smooth rolls) 1.25 1.25 1.25 Cracker -warmer
Continuous feed,Holding and Batch Drop Mills
Blend Mill 1.25 1.25 1.25 (2 smooth rolls) 1.50 1.50 1.50
Compounding Mill 1.25 1.25 1.25 Cracker warmer –2 rolls
Calenders 1.50 1.50 1.50 One corrugated roll 1.75 1.75 1.75
PLASTIC INDUSTRY(Secondary processing) Cracker –
Blow Molders 1.50 1.50 1.50 2 corrugate rolls 2.00 2.00 2.00
Coating 1.25 1.25 1.25 Holding,Feed &
Film 1.25 1.25 1.25 Blend Mill – 2 rolls 1.25 1.25 1.25
Pipe 1.25 1.25 1.25 Refiner – 2 Rolls 1.50 1.50 1.50
Pre-Plasticizers 1.50 1.50 1.50 Calenders 1.50 1.50 1.50
Rods 1.25 1.25 1.25 SAND MULLER 1.25 1.25 1.50
Sheet 1.25 1.25 1.25 SEWAGE DISPOSAL EQUIPMENT
Tubing 1.25 1.25 1.50 Bar screens 1.25 1.25 1.25
PULLERS-BARGE HAUL 1.25 1.25 1.50 Chemical Feeders 1.25 1.25 1.25
PUMPS Dewatering Screens 1.50 1.50 1.50
Centrifugal 1.00 1.00 1.25 Scum Breakers 1.50 1.50 1.50
Proportioning 1.25 1.25 1.50 Slow or rapid mixers 1.50 1.50 1.50
Reciprocating – Single Sludge collectors 1.25 1.25 1.25
Acting,3 or more Cylinders 1.25 1.25 1.50 Thickeners 1.50 1.50 1.50
Reciprocating – Double Vacuum Filters 1.50 1.50 1.50
Acting 2 or more cylinders 1.25 1.25 1.50

 

# Anti-Friction Bearings only. Use 1.5 for sleeve bearings.

** An service factor of 1.00may be applied at base speed of a super calender operating over-speed range  of part range constant horsepower, part range constant torque where the constant horsepower speed range is greater than 1.5 or 1.0. A service factor of 1.25 is applicable to super calenders operating over the entire speed range at constant torque or where the constant horsepower speed range is less than 1.5 to 1.


SERVICE FACTORS FOR ENCLOSED GEAR DRIVES, DRIVEN BY MOTORS (HYDRAULIC & ELECTRIC) AND TURBINES (STEAM OR GAS)

Application

 Load duration/day  

Application

 Load duration/day

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs

Upto 3 Hrs

3 to 10 Hrs

Over 10 Hrs
SCREENS TEXTILE INDUSTRY (Cont.)
Air washing 1.00 1.00 1.25 Dryers 1.25 1.25 1.50
Rotary-Stone or Gravel 1.25 1.25 1.25 Dyeing Machinery 1.25 1.25 1.50
Travelling water intake 1.00 1.00 1.25 Looms 1.25 1.25 1.50
SUGAR INDUSTRY Mangles 1.25 1.25 1.50
Beet Slicer 2.00 2.00 2.00 Nappers 1.25 1.25 1.50
Cane Knives 1.50 1.50 1.50 Pads 1.25 1.25 1.50
Crushers 1.50 1.50 1.50 Slashers 1.25 1.25 1.50
Mills (low speed end) 1.75 1.75 1.75 Soapers 1.25 1.25 1.50
TEXTILE INDUSTRY Spinners 1.25 1.25 1.50
Batchers 1.25 1.25 1.50 Tenter frames 1.25 1.25 1.50
Calenders 1.25 1.25 1.50 Washers 1.25 1.25 1.50
Cards 1.25 1.25 1.50 Winders 1.25 1.25 1.50
Dry Cans 1.25 1.25 1.50