The next is often a sample application utilized to illustrate the normal process for deciding on 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 making use of a 225 horsepower electric motor operating at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electric motor features a 3-3/8 inch shaft by using a 7/8 inch keyway plus the compressor features a 92mm shaft with a 25mm keyway. The shaft separation is approximately 7 inches concerning shaft ends with some skill to alter the motor spot. The shafts possess a parallel misalignment/offset of approximately 1/32 of an inch.
Phase 1: The primary phase is always to figure out what coupling form would be to be chosen for this application. Because the SU Sort coupling only supports
just one flex plane, it may only accommodate angular and axial misalignment, but not parallel misalignment. The following preference can be to search at an SX or DI Variety coupling. The six bolt SX Style will accommodate both parallel misalignment plus the defined shaft separation. The size will probably be determined from the variety torque plus the shaft diameters.
Step 2: Up coming, determine the application torque and apply the services factor to calculate the assortment 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 inside the numbers from the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = twelve,331 in-lbs
Application Torque x Support Component = Assortment Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Stage three: Make use of the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, in excess of ample to handle the assortment torque calculated in stage two. The SX202-6, even so, will not help the 92mm shaft dimension. The next more substantial dimension coupling, the SX228-6, will support the 92mm shaft size plus the shaft separation dimension (BSE) is 6.88 inches, incredibly near to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which could seem to be extreme, having said that, the coupling dimension is important to deal with the bore dimension.
Step four: The SX228-6 coupling is rated for a maximum unbalanced pace of 3,400 RPM, over sufficient to support the application pace of one,150 RPM.
Step five: To determine in the event the coupling will take care of the parallel misalignment, utilize 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 from your table on webpage D-13, or five.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The maximum offset for your application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It really is generally proposed to try to set up the coupling at approximately 20% of your allowable misalignment. For this coupling the installer ought to attempt to accomplish much better than 0.020 parallel misalignment on the time of set up. This will likely enable for the extra misalignment that may occur as the end result of gear settle and general gear dress in.