The next is usually a sample application utilised to illustrate the conventional approach for picking out a Disc coupling. Any resemblance to any existing company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
A company features a compressor application making use of a 225 horsepower electrical motor operating at one,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor includes a 3-3/8 inch shaft that has a 7/8 inch keyway and the compressor features a 92mm shaft by using a 25mm keyway. The shaft separation is approximately seven inches between shaft ends with some capacity to modify the motor spot. The shafts possess a parallel misalignment/offset of approximately 1/32 of an inch.
Phase 1: The very first step is usually to establish what coupling variety is usually to be chosen for this application. Since the SU Sort coupling only supports
just one flex plane, it may possibly only accommodate angular and axial misalignment, but not parallel misalignment. The following selection can be to search at an SX or DI Variety coupling. The 6 bolt SX Style will accommodate each parallel misalignment and the defined shaft separation. The size might be determined through the variety torque as well as the shaft diameters.
Phase two: Following, determine the application torque and apply the services aspect to determine the selection torque.The formula utilized to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging within 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 Services Component = Variety Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Phase three: Use the SX coupling tables and note the SX 202-6 is rated at 40,700 in-lbs, greater than enough to deal with the variety torque calculated in phase 2. The SX202-6, however, will not help the 92mm shaft size. The subsequent bigger dimension coupling, the SX228-6, will support the 92mm shaft size along with the shaft separation dimension (BSE) is 6.88 inches, pretty near to the application?¡¥s sought after seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may perhaps appear to be extreme, even so, the coupling size is important to deal with the bore dimension.
Phase four: The SX228-6 coupling is rated for any maximum unbalanced velocity of 3,400 RPM, more than ample to help the application speed of one,150 RPM.
Phase 5: To determine should the coupling will take care of the parallel misalignment, utilize the trig function of tan 1?? = offset permitted 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 five.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The utmost offset for the application is 1/32 inches (0.031), hence this coupling can accommodate the parallel misalignment.
Note: It is actually generally recommended to try to set up the coupling at approximately 20% in the allowable misalignment. For this coupling the installer need to make an effort to realize superior than 0.020 parallel misalignment at the time of installation. This may let for that more misalignment which will take place since the outcome of tools settle and basic gear wear.