Actions In Deciding on A Disc Coupling

The next is actually a sample application utilised to illustrate the standard approach for deciding on a Disc coupling. Any resemblance to any current company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
An organization features a compressor application working with a 225 horsepower electric motor running at 1,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor includes a 3-3/8 inch shaft having a 7/8 inch keyway and the compressor has a 92mm shaft that has a 25mm keyway. The shaft separation is approximately 7 inches in between shaft ends with some skill to adjust the motor place. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Phase 1: The first step is to establish what coupling form will be to be chosen for this application. Because the SU Variety coupling only supports
just one flex plane, it can only accommodate angular and axial misalignment, but not parallel misalignment. The next preference will be to search at an SX or DI Variety coupling. The 6 bolt SX Style will accommodate the two parallel misalignment as well as the defined shaft separation. The dimension are going to be determined by the assortment torque and the shaft diameters.
Stage two: Next, calculate the application torque and apply the services factor to calculate the selection torque.The formula utilised to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging inside the numbers through the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Support Aspect = Assortment Torque
12,331 in-lbs x 3.0 = 36,993 in-lbs
Step 3: Make use of the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, more than sufficient to deal with the variety torque calculated in step two. The SX202-6, nonetheless, won’t support the 92mm shaft size. The following more substantial dimension coupling, the SX228-6, will support the 92mm shaft size and the shaft separation dimension (BSE) is 6.88 inches, very near to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which could appear to be extreme, nevertheless, the coupling size is necessary to take care of the bore size.
Step four: The SX228-6 coupling is rated to get a maximum unbalanced velocity of 3,400 RPM, greater than enough to support the application pace of 1,150 RPM.
Step five: To find out in the event the coupling will manage the parallel misalignment, utilize the trig function of tan 1?? = offset permitted for 1 inch = 0.0174
Multiply the 0.0174 x the distance involving disc packs or ??S?¡¥ dimension from 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 for your application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It can be often advisable to endeavor to set up the coupling at approximately 20% from the allowable misalignment. For this coupling the installer ought to try and realize improved than 0.020 parallel misalignment in the time of set up. This can make it possible for for your added misalignment that should occur since the outcome of gear settle and common gear put on.