The next can be a sample application employed to illustrate the typical approach for choosing a Disc coupling. Any resemblance to any current company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
An organization features a compressor application utilizing a 225 horsepower electric motor operating at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor has a 3-3/8 inch shaft using a 7/8 inch keyway and also the compressor has a 92mm shaft that has a 25mm keyway. The shaft separation is approximately 7 inches among shaft ends with some skill to alter the motor location. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Step 1: The very first step is usually to determine what coupling type would be to be chosen for this application. Since the SU Style coupling only supports
a single flex plane, it might only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent option would be to seem at an SX or DI Variety coupling. The six bolt SX Form will accommodate the two parallel misalignment as well as defined shaft separation. The dimension will likely be established by the choice torque as well as the shaft diameters.
Phase two: Upcoming, determine the application torque and apply the service element to calculate the assortment torque.The formula utilised to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging in 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 Factor = Variety Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Step three: Use the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, over ample to manage the variety torque calculated in step two. The SX202-6, on the other hand, is not going to support the 92mm shaft dimension. The following more substantial size coupling, the SX228-6, will support the 92mm shaft size and also the shaft separation dimension (BSE) is six.88 inches, pretty close to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may well appear to be excessive, nevertheless, the coupling dimension is necessary to deal with the bore dimension.
Step four: The SX228-6 coupling is rated for a maximum unbalanced speed of 3,400 RPM, a lot more than adequate to help the application pace of one,150 RPM.
Phase 5: To determine if the coupling will take care of the parallel misalignment, make use of the trig perform of tan 1?? = offset permitted for 1 inch = 0.0174
Multiply the 0.0174 x the distance concerning disc packs or ??S?¡¥ dimension through the table on web page D-13, or five.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The maximum offset for the application is 1/32 inches (0.031), hence this coupling can accommodate the parallel misalignment.
Note: It is constantly advisable to attempt to install the coupling at approximately 20% of the allowable misalignment. For this coupling the installer must try to obtain improved than 0.020 parallel misalignment in the time of set up. This will allow for your additional misalignment that can occur because the outcome of gear settle and basic products wear.