The following is usually a sample application applied to illustrate the standard system for deciding on a Disc coupling. Any resemblance to any existing company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s actual application.
Sample Application:
An organization includes a compressor application working with a 225 horsepower electric motor working at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor features a 3-3/8 inch shaft which has a 7/8 inch keyway along with the compressor features a 92mm shaft with a 25mm keyway. The shaft separation is approximately seven inches involving shaft ends with some ability to adjust the motor area. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Stage 1: The primary phase is to decide what coupling sort is usually to be picked for this application. Because the SU Kind coupling only supports
just one flex plane, it may possibly only accommodate angular and axial misalignment, but not parallel misalignment. The next alternative will be to appear at an SX or DI Style coupling. The 6 bolt SX Kind will accommodate both parallel misalignment and also the defined shaft separation. The dimension might be established from the assortment torque plus the shaft diameters.
Step 2: Subsequent, calculate the application torque and apply the services component to determine the choice torque.The formula used to calculate torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging inside 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 Element = Assortment Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Phase 3: Utilize the SX coupling tables and note the SX 202-6 is rated at 40,700 in-lbs, in excess of enough to take care of the assortment torque calculated in stage two. The SX202-6, nevertheless, will not assistance the 92mm shaft size. The subsequent larger dimension coupling, the SX228-6, will assistance the 92mm shaft size plus the shaft separation dimension (BSE) is 6.88 inches, extremely near to the application?¡¥s preferred seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may seem to be extreme, even so, the coupling size is critical to take care of the bore dimension.
Phase 4: The SX228-6 coupling is rated to get a optimum unbalanced pace of three,400 RPM, more than enough to support the application velocity of 1,150 RPM.
Step 5: To determine in case the coupling will deal with the parallel misalignment, utilize the trig function of tan 1?? = offset permitted for one inch = 0.0174
Multiply the 0.0174 x the distance among disc packs or ??S?¡¥ dimension in the table on webpage D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The utmost offset to the application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It truly is always recommended to try and set up the coupling at approximately 20% on the allowable misalignment. For this coupling the installer should really make an effort to reach much better than 0.020 parallel misalignment with the time of installation. This can enable for that further misalignment that should take place since the consequence of products settle and general gear put on.