The following is often a sample application employed to illustrate the regular course of action for selecting a Disc coupling. Any resemblance to any existing company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
A company includes a compressor application making use of a 225 horsepower electric motor working at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor includes a 3-3/8 inch shaft which has a 7/8 inch keyway and also the compressor includes a 92mm shaft having a 25mm keyway. The shaft separation is roughly seven inches in between shaft ends with some potential to change the motor location. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Stage one: The first step will be to determine what coupling kind is always to be selected for this application. Because the SU Style coupling only supports
just one flex plane, it may possibly only accommodate angular and axial misalignment, but not parallel misalignment. The next decision can be to seem at an SX or DI Sort coupling. The six bolt SX Variety will accommodate the two parallel misalignment as well as defined shaft separation. The size are going to be determined from the choice torque and also the shaft diameters.
Phase two: Subsequent, determine the application torque and apply the support factor to calculate the assortment torque.The formula used 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 the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Services Factor = Choice Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Phase 3: Utilize the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, greater than ample to deal with the selection torque calculated in step 2. The SX202-6, nevertheless, won’t help the 92mm shaft size. The next bigger size coupling, the SX228-6, will help the 92mm shaft dimension as well as the shaft separation dimension (BSE) is 6.88 inches, very close to the application?¡¥s wanted seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly seem to be excessive, however, the coupling size is necessary to take care of the bore dimension.
Step 4: The SX228-6 coupling is rated for any greatest unbalanced speed of 3,400 RPM, more than ample to assistance the application velocity of one,150 RPM.
Stage 5: To find out in the event the coupling will handle the parallel misalignment, utilize the trig function of tan 1?? = offset allowed for 1 inch = 0.0174
Multiply the 0.0174 x the distance between disc packs or ??S?¡¥ dimension through the table on webpage D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The utmost offset for your application is 1/32 inches (0.031), thus this coupling can accommodate the parallel misalignment.
Note: It’s generally recommended to make an effort to install the coupling at roughly 20% of your allowable misalignment. For this coupling the installer ought to attempt to realize far better than 0.020 parallel misalignment on the time of set up. This can make it possible for for the extra misalignment that may arise since the outcome of products settle and common products put on.