SELECTION OF THE COUPLINGS 1. Decide service factor for the unit for which the chain coupling is to be fitted by considering the hours of service, type of the power unit etc. from the following table – Service classifi-cation Kinds Characteristics Electric motor or steam turbine Steam or gasoline engine 4 or more cyl. Diesel or Gas Engine. Centrifugal Fans, blowers of pumps conveyor evenly loaded. Even load – 8 hours/day service, Non-reversing-low torque starting. Compressor, conveyor, pulsating load machines, kilns and driers, speeds reducers, Multi cylinder pumps, wood working machines etc. Uneven load – 8 hours / day service, moderate shock or torsional loads, non-reversing. This is the most common type of service. Presses, crushers, impact loads, oil well pumping equipment. Heavy shock load – 8 hours / day service, high peak torsional loads. Reversing under load. Full load starting. For 8 to 16 hrs/day service use next step service factor.For 16 to 25 hours/day service use service factor two step higher loading.

2.Multiply horsepower of driver unit by the service factor. This is the design horsepower.

3. Note the maximum rpm. at which the unit will run and its shaft diameter.

4. From H.P. rating table select the coupling size which is rated equal to or slightly greater than design H.P. required at the rpm. at which the coupling is to operate.

5. Also make sure that the diameter at the shaft is less than the maximum bore permissible on the coupling. If the coupling is not large enough to accommodate the shaft size, use the next coupling which can be bored to suit the shaft requirement.

Lubrication

Couplings operating without cover under fairly clean conditions will give satisfactory service providing they are periodically (weekly) brushed thoroughly with ball grease of medium consistency. Couplings operating with covers should be kept filled with a good quality ball bearing grease of soft or medium consistency.