The next is a sample application applied to illustrate the standard system for selecting 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:
A company features a compressor application applying a 225 horsepower electric motor running at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor has a 3-3/8 inch shaft having a 7/8 inch keyway as well as compressor includes a 92mm shaft using a 25mm keyway. The shaft separation is approximately 7 inches concerning shaft ends with some skill to change the motor spot. The shafts possess a parallel misalignment/offset of approximately 1/32 of an inch.
Phase one: The very first phase will be to determine what coupling form should be to be picked for this application. Since the SU Form coupling only supports
a single flex plane, it could only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent alternative would be to seem at an SX or DI Form coupling. The 6 bolt SX Kind will accommodate the two parallel misalignment as well as defined shaft separation. The dimension is going to be determined from the variety torque and the shaft diameters.
Stage 2: Up coming, determine the application torque and apply the service component to determine 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 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 = Variety Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Stage 3: Make use of the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, greater than adequate to handle the choice torque calculated in phase two. The SX202-6, even so, will not support the 92mm shaft size. The next larger dimension coupling, the SX228-6, will help the 92mm shaft dimension along with the shaft separation dimension (BSE) is 6.88 inches, incredibly close to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may appear to be excessive, even so, the coupling size is necessary to handle the bore size.
Step 4: The SX228-6 coupling is rated to get a highest unbalanced speed of 3,400 RPM, in excess of adequate to support the application pace of one,150 RPM.
Step five: To determine should the coupling will take care of 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 to the application is 1/32 inches (0.031), hence this coupling can accommodate the parallel misalignment.
Note: It is usually encouraged to endeavor to set up the coupling at roughly 20% of the allowable misalignment. For this coupling the installer need to seek to attain greater than 0.020 parallel misalignment with the time of set up. This can permit for your further misalignment that can take place as the result of gear settle and standard equipment wear.