January 26, 2021

The following is usually a sample application applied to illustrate the regular course of action for deciding on 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 applying a 225 horsepower electric motor working at 1,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor features a 3-3/8 inch shaft that has a 7/8 inch keyway and also the compressor includes a 92mm shaft by using a 25mm keyway. The shaft separation is roughly seven inches between shaft ends with some capability to alter the motor place. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Step one: The primary step is usually to ascertain what coupling style will be to be selected for this application. Since the SU Sort coupling only supports
a single flex plane, it might only accommodate angular and axial misalignment, but not parallel misalignment. The next choice could be to seem at an SX or DI Type coupling. The 6 bolt SX Sort will accommodate each parallel misalignment along with the defined shaft separation. The size are going to be determined through the variety torque as well as the shaft diameters.
Stage two: Subsequent, calculate the application torque and apply the support issue to calculate the variety 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 while 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 Services Component = Choice Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Phase 3: Make use of the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, over ample to manage the assortment torque calculated in phase two. The SX202-6, however, won’t assistance the 92mm shaft dimension. The subsequent more substantial size coupling, the SX228-6, will assistance the 92mm shaft dimension as well as shaft separation dimension (BSE) is six.88 inches, incredibly close to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly appear to be extreme, even so, the coupling dimension is necessary to deal with the bore dimension.
Phase 4: The SX228-6 coupling is rated to get a highest unbalanced pace of three,400 RPM, over ample to assistance the application speed of 1,150 RPM.
Stage 5: To find out in case the coupling will deal with the parallel misalignment, utilize the trig perform 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 for the application is 1/32 inches (0.031), thus this coupling can accommodate the parallel misalignment.
Note: It’s constantly proposed to try and set up the coupling at roughly 20% with the allowable misalignment. For this coupling the installer really should attempt to reach better than 0.020 parallel misalignment at the time of installation. This may let to the additional misalignment that will happen since the outcome of products settle and common products wear.