The next is a sample application made use of to illustrate the common process 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 has a compressor application working with a 225 horsepower electrical motor operating at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor features a 3-3/8 inch shaft having a 7/8 inch keyway plus the compressor has a 92mm shaft by using a 25mm keyway. The shaft separation is roughly 7 inches amongst shaft ends with some means to adjust the motor area. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Step one: The initial stage would be to establish what coupling variety will be to be chosen for this application. Since the SU Sort coupling only supports
a single flex plane, it may only accommodate angular and axial misalignment, but not parallel misalignment. The following preference would be to look at an SX or DI Form coupling. The 6 bolt SX Type will accommodate both parallel misalignment as well as the defined shaft separation. The size will probably be established by the assortment torque along with the shaft diameters.
Step 2: Following, calculate the application torque and apply the service element to determine the selection torque.The formula employed to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging during the numbers in the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = twelve,331 in-lbs
Application Torque x Support Element = Assortment Torque
12,331 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 40,700 in-lbs, a lot more than sufficient to take care of the choice torque calculated in phase two. The SX202-6, on the other hand, is not going to support the 92mm shaft dimension. The subsequent greater dimension coupling, the SX228-6, will assistance the 92mm shaft size plus the shaft separation dimension (BSE) is six.88 inches, really near to the application?¡¥s sought after 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may perhaps appear to be excessive, nonetheless, the coupling size is critical to handle the bore size.
Stage four: The SX228-6 coupling is rated to get a optimum unbalanced pace of 3,400 RPM, over sufficient to help the application pace of one,150 RPM.
Phase five: To determine if your coupling will manage the parallel misalignment, make use of the trig perform of tan 1?? = offset permitted for one inch = 0.0174
Multiply the 0.0174 x the distance amongst disc packs or ??S?¡¥ dimension in the table on page D-13, or five.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 can be usually advisable to endeavor to set up the coupling at roughly 20% in the allowable misalignment. For this coupling the installer really should try and achieve superior than 0.020 parallel misalignment with the time of installation. This will permit to the added misalignment that will occur as the end result of gear settle and standard equipment dress in.