The following is actually a sample application made use of to illustrate the normal approach for picking a Disc coupling. Any resemblance to any present company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
An organization includes a compressor application applying a 225 horsepower electric motor working at 1,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor includes a 3-3/8 inch shaft which has a 7/8 inch keyway and the compressor features a 92mm shaft using a 25mm keyway. The shaft separation is roughly 7 inches involving shaft ends with some skill to adjust the motor place. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Stage one: The primary phase is always to establish what coupling form is to be chosen 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 following choice will be to look at an SX or DI Type coupling. The six bolt SX Variety will accommodate the two parallel misalignment plus the defined shaft separation. The dimension are going to be determined through the variety torque as well as the shaft diameters.
Stage 2: Next, calculate the application torque and apply the support aspect to determine the choice torque.The formula applied to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging from 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 Support Component = Choice Torque
twelve,331 in-lbs x 3.0 = 36,993 in-lbs
Step 3: Make use of the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, greater than sufficient to deal with the assortment torque calculated in stage 2. The SX202-6, nonetheless, will not support the 92mm shaft dimension. The following bigger size coupling, the SX228-6, will help the 92mm shaft dimension as well as shaft separation dimension (BSE) is 6.88 inches, incredibly near to the application?¡¥s sought after 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may perhaps appear to be extreme, having said that, the coupling size is important to deal with the bore dimension.
Stage 4: The SX228-6 coupling is rated for a greatest unbalanced speed of 3,400 RPM, in excess of enough to assistance the application speed of 1,150 RPM.
Phase five: To determine in the event the coupling will manage the parallel misalignment, use the trig perform of tan 1?? = offset permitted for one inch = 0.0174
Multiply the 0.0174 x the distance involving disc packs or ??S?¡¥ dimension in the table on page D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The maximum offset for the application is 1/32 inches (0.031), for that reason this coupling can accommodate the parallel misalignment.
Note: It is constantly advisable to try and set up the coupling at approximately 20% of the allowable misalignment. For this coupling the installer need to try and realize improved than 0.020 parallel misalignment with the time of installation. This can allow for your more misalignment that could take place as the outcome of gear settle and common gear wear.