The following can be a sample application made use of to illustrate the regular method for picking a Disc coupling. Any resemblance to any current company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s actual application.
Sample Application:
An organization features a compressor application employing a 225 horsepower electric motor running at one,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor has a 3-3/8 inch shaft with a 7/8 inch keyway and also the compressor has a 92mm shaft having a 25mm keyway. The shaft separation is approximately 7 inches in between shaft ends with some potential to adjust the motor location. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Step 1: The initial step will be to establish what coupling kind is to be chosen for this application. Since the SU Type coupling only supports
a single flex plane, it might only accommodate angular and axial misalignment, but not parallel misalignment. The next option might be to seem at an SX or DI Variety coupling. The six bolt SX Style will accommodate each parallel misalignment plus the defined shaft separation. The size are going to be determined from the selection torque and also the shaft diameters.
Step 2: Subsequent, determine the application torque and apply the services issue to determine the variety torque.The formula made use of to calculate torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging within 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 Aspect = Selection Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Stage three: Use the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, over sufficient to deal with the choice torque calculated in stage 2. The SX202-6, however, will not help the 92mm shaft size. The next bigger size coupling, the SX228-6, will assistance the 92mm shaft size as well as shaft separation dimension (BSE) is 6.88 inches, pretty near to the application?¡¥s wanted 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may well appear to be excessive, on the other hand, the coupling dimension is critical to manage the bore size.
Step four: The SX228-6 coupling is rated for any maximum unbalanced pace of 3,400 RPM, over enough to support the application velocity of one,150 RPM.
Stage 5: To find out if your 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 in between disc packs or ??S?¡¥ dimension in the table on web page D-13, or 5.50 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), as a result this coupling can accommodate the parallel misalignment.
Note: It is actually usually advisable to seek to install the coupling at roughly 20% of the allowable misalignment. For this coupling the installer need to endeavor to realize superior than 0.020 parallel misalignment with the time of set up. This may enable for the further misalignment that can arise since the consequence of tools settle and general gear wear.