The next is actually a sample application used to illustrate the common process for selecting 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 has a compressor application utilizing a 225 horsepower electrical motor running at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor includes a 3-3/8 inch shaft with a 7/8 inch keyway along with the compressor has a 92mm shaft which has a 25mm keyway. The shaft separation is approximately 7 inches among shaft ends with some potential to adjust the motor spot. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Stage one: The 1st stage should be to determine what coupling kind is to be chosen for this application. Because the SU Style coupling only supports
just one flex plane, it may possibly only accommodate angular and axial misalignment, but not parallel misalignment. The following selection can be to look at an SX or DI Sort coupling. The 6 bolt SX Form will accommodate the two parallel misalignment as well as defined shaft separation. The dimension will probably be determined from the selection torque plus the shaft diameters.
Phase 2: Following, determine the application torque and apply the service component to determine the assortment 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 during the numbers from the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Support Aspect = Assortment Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Step three: Utilize the SX coupling tables and note the SX 202-6 is rated at 40,700 in-lbs, a lot more than enough to take care of the selection torque calculated in step 2. The SX202-6, nonetheless, is not going to help the 92mm shaft size. The next bigger dimension coupling, the SX228-6, will help the 92mm shaft size and also the shaft separation dimension (BSE) is six.88 inches, very close to the application?¡¥s wanted 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 dimension is important to take care of the bore dimension.
Step four: The SX228-6 coupling is rated for any maximum unbalanced velocity of three,400 RPM, a lot more than enough to help the application pace of 1,150 RPM.
Step five: To determine should the coupling will take care of the parallel misalignment, use the trig function of tan 1?? = offset permitted for one inch = 0.0174
Multiply the 0.0174 x the distance involving disc packs or ??S?¡¥ dimension from your 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 to the application is 1/32 inches (0.031), therefore this coupling can accommodate the parallel misalignment.
Note: It truly is normally suggested to seek to set up the coupling at approximately 20% of the allowable misalignment. For this coupling the installer should try and attain far better than 0.020 parallel misalignment on the time of installation. This can allow for the further misalignment that can arise as the end result of gear settle and basic equipment put on.