The next is really a sample application employed to illustrate the typical process for picking out a Disc coupling. Any resemblance to any current company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s actual application.
Sample Application:
An organization features a compressor application using a 225 horsepower electrical motor running at one,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electric motor includes a 3-3/8 inch shaft with a 7/8 inch keyway as well as compressor has a 92mm shaft having a 25mm keyway. The shaft separation is approximately 7 inches amongst shaft ends with some capacity to modify the motor area. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Stage 1: The initial phase should be to decide what coupling sort is to be chosen for this application. Because the SU Form coupling only supports
just one flex plane, it can only accommodate angular and axial misalignment, but not parallel misalignment. The following selection could be to appear at an SX or DI Style coupling. The six bolt SX Type will accommodate the two parallel misalignment as well as defined shaft separation. The dimension will probably be determined from the selection torque plus the shaft diameters.
Phase two: Up coming, calculate the application torque and apply the service issue to calculate the choice torque.The formula utilised to calculate torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging in the numbers in the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = twelve,331 in-lbs
Application Torque x Support Element = Variety Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Phase 3: Utilize the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, more than sufficient to handle the variety torque calculated in step two. The SX202-6, nonetheless, won’t help the 92mm shaft dimension. The subsequent larger size coupling, the SX228-6, will assistance the 92mm shaft dimension as well as shaft separation dimension (BSE) is 6.88 inches, extremely near to the application?¡¥s sought after 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly appear to be excessive, having said that, the coupling size is critical to deal with the bore size.
Stage 4: The SX228-6 coupling is rated for a optimum unbalanced velocity of 3,400 RPM, greater than adequate to assistance the application pace of 1,150 RPM.
Phase 5: To find out should the coupling will manage the parallel misalignment, use the trig perform of tan 1?? = offset allowed for 1 inch = 0.0174
Multiply the 0.0174 x the distance amongst disc packs or ??S?¡¥ dimension through the table on web page D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The maximum offset to the application is 1/32 inches (0.031), hence this coupling can accommodate the parallel misalignment.
Note: It is generally recommended to try and install the coupling at roughly 20% with the allowable misalignment. For this coupling the installer must make an effort to attain greater than 0.020 parallel misalignment on the time of installation. This can make it possible for for the supplemental misalignment which will take place because the consequence of products settle and general tools wear.