The following is a sample application utilized to illustrate the typical procedure for picking 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 has a compressor application making use of a 225 horsepower electrical motor working at one,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electric motor features a 3-3/8 inch shaft which has a 7/8 inch keyway plus the compressor includes a 92mm shaft using a 25mm keyway. The shaft separation is roughly seven inches concerning shaft ends with some capacity to change the motor spot. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Stage one: The primary phase will be to figure out what coupling sort is always to be selected for this application. Since the SU Kind coupling only supports
just one flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent decision would be to appear at an SX or DI Kind coupling. The six bolt SX Variety will accommodate each parallel misalignment as well as defined shaft separation. The dimension is going to be established through the choice torque plus the shaft diameters.
Step 2: Following, determine the application torque and apply the service issue to calculate the variety torque.The formula used 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 Component = Variety Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Phase 3: Use the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, in excess of ample to handle the selection torque calculated in stage two. The SX202-6, however, will not help the 92mm shaft dimension. The next bigger size coupling, the SX228-6, will help the 92mm shaft dimension plus the shaft separation dimension (BSE) is six.88 inches, incredibly near to the application?¡¥s wanted seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may appear to be extreme, having said that, the coupling dimension is important to manage the bore size.
Stage 4: The SX228-6 coupling is rated for a greatest unbalanced pace of 3,400 RPM, in excess of adequate to help the application speed of one,150 RPM.
Phase five: To find out if the coupling will handle 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 through 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 for the application is 1/32 inches (0.031), hence this coupling can accommodate the parallel misalignment.
Note: It really is always suggested to make an effort to install the coupling at approximately 20% of your allowable misalignment. For this coupling the installer should really attempt to attain greater than 0.020 parallel misalignment with the time of set up. This will enable for the extra misalignment that may arise because the result of equipment settle and general equipment wear.