The following is a sample application utilised to illustrate the regular method for picking 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:
A company features a compressor application employing a 225 horsepower electrical motor working 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 as well as the compressor includes a 92mm shaft which has a 25mm keyway. The shaft separation is approximately 7 inches in between shaft ends with some capability to adjust the motor place. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Step one: The first step is always to figure out what coupling kind is to be chosen for this application. Since the SU Form coupling only supports
just one flex plane, it may only accommodate angular and axial misalignment, but not parallel misalignment. The next decision could be to look at an SX or DI Sort coupling. The six bolt SX Kind will accommodate both parallel misalignment and the defined shaft separation. The size is going to be established by the variety torque as well as shaft diameters.
Stage two: Subsequent, determine the application torque and apply the services aspect to calculate the variety torque.The formula employed to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging while in 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 Support Factor = Choice Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Phase 3: Make use of the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, in excess of adequate to manage the selection torque calculated in step 2. The SX202-6, even so, won’t assistance the 92mm shaft dimension. The following bigger size coupling, the SX228-6, will assistance the 92mm shaft dimension as well as the shaft separation dimension (BSE) is 6.88 inches, really near to the application?¡¥s wanted 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may perhaps seem to be excessive, on the other hand, the coupling dimension is critical to take care of the bore dimension.
Stage four: The SX228-6 coupling is rated for any highest unbalanced pace of 3,400 RPM, more than adequate to support the application speed of one,150 RPM.
Step five: To determine in the event the coupling will take care of the parallel misalignment, make use of the trig perform of tan 1?? = offset allowed for one 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), as a result this coupling can accommodate the parallel misalignment.
Note: It can be always recommended to make an effort to set up the coupling at roughly 20% of your allowable misalignment. For this coupling the installer ought to try and achieve far better than 0.020 parallel misalignment in the time of installation. This can make it possible for for that supplemental misalignment that should arise because the end result of gear settle and basic gear dress in.