The following is really a sample application made use of to illustrate the typical system for picking a Disc coupling. Any resemblance to any existing company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
A company has a compressor application utilizing a 225 horsepower electric motor operating at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electric motor has a 3-3/8 inch shaft with a 7/8 inch keyway as well as the compressor has a 92mm shaft with a 25mm keyway. The shaft separation is roughly seven inches in between shaft ends with some capability to change the motor area. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Phase 1: The 1st step should be to identify what coupling sort would be to be selected for this application. Since the SU Sort coupling only supports
a single flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The next alternative might be to search at an SX or DI Style coupling. The 6 bolt SX Kind will accommodate the two parallel misalignment plus the defined shaft separation. The dimension will be determined from the assortment torque and also the shaft diameters.
Stage 2: Upcoming, determine the application torque and apply the service element to calculate the choice torque.The formula utilised to calculate torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging in 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 Service Factor = Choice Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Stage three: Use the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, greater than sufficient to take care of the choice torque calculated in stage two. The SX202-6, having said that, will not assistance the 92mm shaft size. The next greater dimension coupling, the SX228-6, will help the 92mm shaft dimension and the shaft separation dimension (BSE) is 6.88 inches, extremely close to the application?¡¥s sought after 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly seem to be extreme, on the other hand, the coupling size is critical to handle the bore dimension.
Phase 4: The SX228-6 coupling is rated to get a highest unbalanced speed of three,400 RPM, in excess of sufficient to assistance the application velocity of one,150 RPM.
Stage five: To determine when the coupling will handle 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 concerning disc packs or ??S?¡¥ dimension in 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 your application is 1/32 inches (0.031), thus this coupling can accommodate the parallel misalignment.
Note: It can be normally encouraged to try to install the coupling at roughly 20% of the allowable misalignment. For this coupling the installer need to endeavor to achieve greater than 0.020 parallel misalignment on the time of set up. This will likely enable for that further misalignment that can come about as the outcome of products settle and general products wear.