The selection of coupling size and type will be dependant on several factors. The first requirement must obviously be to choose a unit of adequate size of transmit the maximum torque and for this purpose it is advisable to use the actual available power of the driving machine rather than the calculated absorbed power of the driven machine, unless this latter is known not be exceeded.

Having determined the maximum HP or KW to be transmitted, this is divided by the speed to give the HP or KW/rpm so that, by comparison with the technical data, a selection can be made from any of the various coupling types. If the type of application demands the use of a Service Factor this should be applied before selecting the coupling size. If the resulting specific rating falls between two coupling size, the larger should be selected.

The standard coupling will withstand a short circuit torque (C.C.) of 2,5 times the nominal torque. When the C.C. exceeds 2,5 times nominal size the coupling from:


HP (KW x 1,36) x 716,2 x 9,81 x C.C. x Service factor


rpm/1’ x 2,5 x Nominal torque


For direct on line motors, where the starting torque does not exceed 2 x nominal, use a Service Factor of 1,5, unless the Service Factor already applied for the particular application is 1,5 or greater, in wich case no Service Factor need be applied; if the starting torque is greather than 2 x nominal,determine the required size from:


HP (KW x 1,36) x 716,2 x 9,81
Max expected torque
Nominal torque =
1,5 x Nominal torque


Having determined the coupling rating, the required flexibility must be considered from an assessment of the shaft movements, comparing these with relative technical data.

A final check should be made to ensure that the maximum hub bore dimension is adequate for the shaft. Providing, after the selection is made, other factors such as weight, torsional stiffness etc, as given in the appropriate tables are acceptable then a standard unit can be selected. If not consult our technical department who are always willing to give advice and produce special designs outside the chartsue dimensions if required.

It should be noted that, throughout the chartsue, the coupling size indicates its rated capacity in Nm: for instance coupling LSDA 1700-6 is an 6 bolt coupling with a rated capacity of 1700 Nm.




  • Complete metallic construction: Hubs, adapters, spacers: Uni 7845 C45; Flexible elements: AISI 304 C; Monel; Bolts: Uni 5933 10.9;
  • Possibility of complete AISI construction;
  • No lubrication is required;
  • Operation in both directions of rotation;
  • Operation in adverse environmental conditions;
  • High temperature operation;
  • High balancing quality because of precise manufacturing (AGMA 9000 Class 9);
  • Execution to API 610 (all standard range LSDA);
  • Execution to API 671 (LSDA range on request);
  • No sparking execution;
  • No maintenance;
  • High torque with low weight;
  • Long working life;
  • Angular misalignment;
  • Parallel misalignment (for spacer range);
  • Axial misalignment(for spacer range);
  • Possibility to adjust the axial stroke (for spacer range);
  • Torsional stiffness shug also with reversal torque;
  • Limited axial thrust.