The next is really a sample application employed to illustrate the conventional 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:
An organization has a compressor application employing a 225 horsepower electric motor working at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor includes a 3-3/8 inch shaft with a 7/8 inch keyway as well as compressor has a 92mm shaft by using a 25mm keyway. The shaft separation is roughly seven inches between shaft ends with some potential to adjust the motor location. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Phase one: The 1st phase should be to decide what coupling variety is usually to be selected 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 subsequent alternative could be to search at an 
SX or DI Sort coupling. The 6 bolt SX Form will accommodate the two parallel misalignment and the defined shaft separation. The dimension might be determined through the variety torque as well as shaft diameters.
Stage 2: Upcoming, calculate the application torque and apply the services component to calculate the assortment 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 from your application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = twelve,331 in-lbs
Application Torque x Support Factor = Assortment Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Step 3: Use the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, more than enough to handle the choice torque calculated in phase two. The SX202-6, nevertheless, will not help the 92mm shaft size. The following greater size coupling, the SX228-6, will support the 92mm shaft dimension as well as shaft separation dimension (BSE) is six.88 inches, pretty near to the application?¡¥s sought after seven inch separation. The SX228-6 is rated at 62,000 in-lbs which might appear to be extreme, however, the coupling dimension is important to take care of the bore size.
Phase 4: The SX228-6 coupling is rated to get a maximum unbalanced velocity of 3,400 RPM, more than ample to support the application speed of one,150 RPM.
Phase five: To find out when the coupling will deal with the parallel misalignment, make use of 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 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), therefore this coupling can accommodate the parallel misalignment.
Note: It truly is usually advised to try and install the coupling at approximately 20% of the allowable misalignment. For this coupling the installer should make an effort to obtain superior than 0.020 parallel misalignment at the time of set up. This may let for your further misalignment that could come about since the outcome of equipment settle and general equipment wear.
