The next is really a sample application applied to illustrate the regular approach for choosing 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 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 that has a 7/8 inch keyway as well as compressor features a 92mm shaft using a 25mm keyway. The shaft separation is approximately seven inches amongst shaft ends with some skill to adjust the motor location. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Stage one: The initial stage would be to decide what coupling variety should be to be chosen for this application. Since the SU Form coupling only supports
just one flex plane, it might only accommodate angular and axial misalignment, but not parallel misalignment. The following preference will be to look at an SX or DI Type coupling. The six bolt SX Sort will accommodate the two parallel misalignment along with the defined shaft separation. The size might be established from the variety torque as well as the shaft diameters.
Stage two: Next, calculate the application torque and apply the support aspect to determine the choice torque.The formula utilised 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 from your application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Support Issue = Selection Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Step 3: Make use of the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, more than enough to deal with the assortment torque calculated in stage two. The SX202-6, nevertheless, is not going to support the 92mm shaft size. The following bigger dimension coupling, the SX228-6, will help the 92mm shaft dimension plus the shaft separation dimension (BSE) is six.88 inches, quite near to the application?¡¥s wanted 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may well seem to be extreme, having said that, the coupling dimension is important to handle the bore dimension.
Stage 4: The SX228-6 coupling is rated for any greatest unbalanced speed of three,400 RPM, a lot more than enough to support the application velocity of one,150 RPM.
Phase 5: To find out in the event the coupling will manage the parallel misalignment, utilize the trig perform of tan 1?? = offset permitted for one inch = 0.0174
Multiply the 0.0174 x the distance amongst disc packs or ??S?¡¥ dimension from the table on webpage D-13, or five.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The maximum offset for the application is 1/32 inches (0.031), as a result this coupling can accommodate the parallel misalignment.
Note: It is actually often advisable to make an effort to set up the coupling at approximately 20% of your allowable misalignment. For this coupling the installer must make an effort to obtain superior than 0.020 parallel misalignment on the time of installation. This can make it possible for for your more misalignment that may happen since the result of equipment settle and general equipment dress in.