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January 26, 2021

The next can be a sample application utilised to illustrate the common procedure 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 has a compressor application making use of a 225 horsepower electrical motor operating at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electric motor has a 3-3/8 inch shaft that has a 7/8 inch keyway along with the compressor features a 92mm shaft which has a 25mm keyway. The shaft separation is approximately 7 inches involving shaft ends with some means to alter the motor area. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Stage 1: The very first stage would be to establish what coupling kind is always to be picked for this application. Because the SU Variety coupling only supports
a single flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent option can be to look at an SX or DI Kind coupling. The 6 bolt SX Sort will accommodate each parallel misalignment plus the defined shaft separation. The size will be determined from the choice torque as well as shaft diameters.
Step two: Next, calculate the application torque and apply the service factor to determine the assortment torque.The formula made use of to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging during 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 Aspect = Choice Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Phase three: Utilize the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, greater than enough to manage the assortment torque calculated in step two. The SX202-6, on the other hand, will not support the 92mm shaft dimension. The subsequent greater size coupling, the SX228-6, will help the 92mm shaft size as well as the shaft separation dimension (BSE) is six.88 inches, quite near to the application?¡¥s wanted seven inch separation. The SX228-6 is rated at 62,000 in-lbs which might appear to be extreme, on the other hand, the coupling size is necessary to manage the bore dimension.
Stage 4: The SX228-6 coupling is rated for a optimum unbalanced velocity of 3,400 RPM, over enough to assistance the application velocity of one,150 RPM.
Step 5: To find out in the event the coupling will deal with the parallel misalignment, make use of the trig function of tan 1?? = offset allowed for 1 inch = 0.0174
Multiply the 0.0174 x the distance in between disc packs or ??S?¡¥ dimension from 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 to the application is 1/32 inches (0.031), thus this coupling can accommodate the parallel misalignment.
Note: It can be always recommended to attempt to install the coupling at approximately 20% with the allowable misalignment. For this coupling the installer really should make an effort to achieve better than 0.020 parallel misalignment in the time of installation. This will permit for your supplemental misalignment which will arise since the outcome of gear settle and basic equipment put on.