The following is really a sample application used to illustrate the typical method for deciding on 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 has a compressor application applying a 225 horsepower electric motor operating at 1,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor features a 3-3/8 inch shaft using a 7/8 inch keyway as well as compressor has a 92mm shaft that has a 25mm keyway. The shaft separation is approximately seven inches involving shaft ends with some ability to modify the motor spot. The shafts possess a parallel misalignment/offset of approximately 1/32 of an inch.
Step 1: The primary phase is always to ascertain what coupling style should be to be picked for this application. Since the SU Variety coupling only supports
just one flex plane, it might only accommodate angular and axial misalignment, but not parallel misalignment. The following choice could be to appear at an SX or DI Style coupling. The 6 bolt SX Kind will accommodate each parallel misalignment along with the defined shaft separation. The dimension will likely be established by the selection torque plus the shaft diameters.
Stage 2: 
Upcoming, calculate the application torque and apply the services issue to determine 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 from your application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = twelve,331 in-lbs
Application Torque x Service Element = Assortment Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Stage three: Make use of the SX coupling tables and note the SX 202-6 is rated at 40,700 in-lbs, in excess of adequate to take care of the variety torque calculated in phase two. The SX202-6, having said that, will not assistance the 92mm shaft dimension. The subsequent more substantial size coupling, the SX228-6, will assistance the 92mm shaft size as well as shaft separation dimension (BSE) is 6.88 inches, quite near to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may appear to be extreme, even so, the coupling dimension is important to deal with the bore dimension.
Phase four: The SX228-6 coupling is rated to get a optimum unbalanced velocity of three,400 RPM, a lot more than adequate to help the application pace of 1,150 RPM.
Step five: To find out should the coupling will manage 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 in the table on web page D-13, or five.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The maximum offset for that application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It is actually often encouraged to seek to set up the coupling at approximately 20% on the allowable misalignment. For this coupling the installer should really endeavor to attain improved than 0.020 parallel misalignment at the time of installation. This will enable for that more misalignment which will happen because the consequence of gear settle and general gear dress in.
