The next is a sample application made use of to illustrate the common approach for choosing 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:
An organization features a compressor application utilizing a 225 horsepower 
electric motor running at 1,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor has a 3-3/8 inch shaft having a 7/8 inch keyway along with the compressor has a 92mm shaft with a 25mm keyway. The shaft separation is roughly 7 inches in between shaft ends with some ability to alter the motor location. The shafts possess a parallel misalignment/offset of approximately 1/32 of an inch.
Step 1: The initial step is to decide what coupling variety would be to be selected for this application. Because the SU Style coupling only supports
just one flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent selection might be to appear at an SX or DI Style coupling. The 6 bolt SX Sort will accommodate both parallel misalignment and also the defined shaft separation. The size will likely be determined through the variety torque plus the shaft diameters.
Phase two: Upcoming, calculate the application torque and apply the service issue to determine the assortment torque.The formula employed 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 through the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = twelve,331 in-lbs
Application Torque x Services Factor = Selection Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Stage 3: Make use of the SX coupling tables and note the SX 202-6 is rated at 40,700 in-lbs, more than sufficient to take care of the choice torque calculated in step 2. The SX202-6, nonetheless, won’t assistance the 92mm shaft dimension. The following more substantial dimension coupling, the SX228-6, will assistance the 92mm shaft size plus the shaft separation dimension (BSE) is six.88 inches, really near to the application?¡¥s sought after seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly seem to be excessive, even so, the coupling dimension is necessary to manage the bore size.
Stage 4: The SX228-6 coupling is rated for a greatest unbalanced pace of three,400 RPM, greater than ample to help the application speed of one,150 RPM.
Step 5: To determine when 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 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 five.50 = 0.096 inches. The utmost offset for your application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It is constantly encouraged to endeavor to set up the coupling at approximately 20% on the allowable misalignment. For this coupling the installer must try and attain far better than 0.020 parallel misalignment in the time of set up. This will likely make it possible for to the additional misalignment that can happen as the end result of tools settle and general tools dress in.
