January 26, 2021

The next is a sample application used to illustrate the regular course of action for deciding on 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:
An organization has a compressor application making use of a 225 horsepower electrical motor operating at one,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor includes a 3-3/8 inch shaft which has a 7/8 inch keyway along with the compressor includes a 92mm shaft which has a 25mm keyway. The shaft separation is roughly seven inches involving shaft ends with some ability to change the motor spot. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Phase 1: The very first phase will be to figure out what coupling style will be to be selected for this application. Since the SU Style coupling only supports
just one flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent option could be to search at an SX or DI Type coupling. The six bolt SX Type will accommodate each parallel misalignment as well as defined shaft separation. The size are going to be established through the selection torque and the shaft diameters.
Stage 2: Up coming, determine the application torque and apply the services issue to calculate the selection torque.The formula employed to calculate torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging while in 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 Service Issue = Selection Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Phase three: Use the SX coupling tables and note that the SX 202-6 is rated at 40,700 in-lbs, more than sufficient to take care of the assortment torque calculated in phase two. The SX202-6, however, is not going to support the 92mm shaft size. The next larger dimension coupling, the SX228-6, will support the 92mm shaft dimension as well as the shaft separation dimension (BSE) is 6.88 inches, very close to the application?¡¥s preferred 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which could appear to be excessive, nevertheless, the coupling size is important to deal with the bore dimension.
Phase 4: The SX228-6 coupling is rated for any maximum unbalanced velocity of 3,400 RPM, over sufficient to support the application speed of 1,150 RPM.
Stage five: To determine if your coupling will take care of 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 through the table on webpage D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The utmost offset for that application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It can be always proposed to endeavor to install the coupling at approximately 20% on the allowable misalignment. For this coupling the installer must try and attain better than 0.020 parallel misalignment in the time of set up. This will allow for your further misalignment that may happen since the result of equipment settle and basic gear put on.