Ways In Choosing A Disc Coupling

The next is often a sample application used to illustrate the standard approach for picking a Disc coupling. Any resemblance to any present company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s actual application.
Sample Application:
An organization features a compressor application working with a 225 horsepower electric motor operating at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor features a 3-3/8 inch shaft having a 7/8 inch keyway and also the compressor has a 92mm shaft using a 25mm keyway. The shaft separation is roughly seven inches between shaft ends with some skill to adjust the motor spot. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Stage 1: The primary step should be to establish what coupling sort would be to be chosen for this application. Since the SU Kind coupling only supports
just one flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The following selection would be to seem at an SX or DI Sort coupling. The six bolt SX Type will accommodate each parallel misalignment as well as defined shaft separation. The size will be determined from the choice torque as well as the shaft diameters.
Step two: Up coming, determine the application torque and apply the services component to determine the assortment torque.The formula used to calculate 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 = twelve,331 in-lbs
Application Torque x Service Aspect = Selection Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Stage three: Use the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, over adequate to manage the variety torque calculated in phase 2. The SX202-6, nevertheless, won’t support the 92mm shaft size. The next greater dimension coupling, the SX228-6, will help the 92mm shaft dimension and the shaft separation dimension (BSE) is 6.88 inches, very near to the application?¡¥s preferred seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may perhaps seem to be extreme, having said that, the coupling size is critical to manage the bore size.
Step four: The SX228-6 coupling is rated for a maximum unbalanced pace of 3,400 RPM, a lot more than sufficient to assistance the application velocity of 1,150 RPM.
Phase five: To find out should the coupling will deal with the parallel misalignment, utilize the trig function of tan 1?? = offset allowed for one inch = 0.0174
Multiply the 0.0174 x the distance in between disc packs or ??S?¡¥ dimension from your table on webpage D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The maximum offset to the application is 1/32 inches (0.031), as a result this coupling can accommodate the parallel misalignment.
Note: It is always encouraged to try to install the coupling at roughly 20% from the allowable misalignment. For this coupling the installer really should seek to reach improved than 0.020 parallel misalignment at the time of installation. This can let for your added misalignment that may come about since the consequence of products settle and common tools put on.