The following is a sample application employed to illustrate the normal course of action for selecting a Disc coupling. Any resemblance to any present company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s actual application.
Sample Application:
An organization has a compressor application making use of a 225 horsepower electrical motor working at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor has a 3-3/8 inch shaft having a 7/8 inch keyway and also the compressor has a 92mm shaft which has a 25mm keyway. The shaft separation is roughly seven inches between shaft ends with some skill to adjust the motor location. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Stage 1: The primary stage is always to determine what coupling variety is always to be selected for this application. Since the SU Variety coupling only supports
a single flex plane, it could only accommodate angular and axial misalignment, but not parallel misalignment. The next alternative could be to search at an SX or DI Style coupling. The 6 bolt SX Style will accommodate both parallel misalignment as well as defined shaft separation. The size is going to be determined by the selection torque as well as the shaft diameters.
Stage two: 
Subsequent, determine the application torque and apply the support component to calculate the selection torque.The formula employed to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging from the numbers through the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Service Issue = Assortment Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Step three: Utilize the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, over adequate to manage the choice torque calculated in step 2. The SX202-6, having said that, will not support the 92mm shaft size. The following greater size coupling, the SX228-6, will help the 92mm shaft size and the shaft separation dimension (BSE) is six.88 inches, really close to the application?¡¥s sought after 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which could appear to be extreme, nonetheless, the coupling dimension is critical to handle the bore dimension.
Step 4: The SX228-6 coupling is rated to get a maximum unbalanced pace of 3,400 RPM, greater than ample to assistance the application pace of 1,150 RPM.
Phase five: To determine in case the coupling will handle the parallel misalignment, utilize the trig perform of tan 1?? = offset allowed for 1 inch = 0.0174
Multiply the 0.0174 x the distance involving disc packs or ??S?¡¥ dimension from the table on webpage D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The maximum offset for that application is 1/32 inches (0.031), therefore this coupling can accommodate the parallel misalignment.
Note: It truly is always recommended to attempt to install the coupling at approximately 20% of your allowable misalignment. For this coupling the installer should really seek to reach far better than 0.020 parallel misalignment on the time of set up. This will enable for your more misalignment that should come about since the result of tools settle and common equipment dress in.
