The following can be a sample application used to illustrate the common method for deciding on a Disc coupling. Any resemblance to any present company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
An organization has a compressor application working with a 225 horsepower electric motor working at one,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electric motor includes a 3-3/8 inch shaft that has a 7/8 inch keyway as well as compressor has a 92mm shaft which has a 25mm keyway. The shaft separation is approximately seven inches in between shaft ends with some means to modify the motor area. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Phase 1: The initial step should be to ascertain what coupling form is to be picked for this application. Since the SU Form coupling only supports
a single flex plane, it may only accommodate angular and axial misalignment, but not parallel misalignment. The following decision can be to seem at an SX or DI Kind coupling. The 6 bolt SX Variety will accommodate the two parallel misalignment along with the defined shaft separation. The size will likely be established by the variety torque as well as the shaft diameters.
Step two: Next, calculate the application torque and apply the service factor 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 from 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 Service Factor = Assortment Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Stage 3: Utilize the SX coupling tables and note the SX 202-6 is rated at 40,700 in-lbs, in excess of enough to deal with the choice torque calculated in phase 2. The SX202-6, having said that, won’t support the 92mm shaft dimension. The following larger dimension coupling, the SX228-6, will support the 92mm shaft dimension as well as shaft separation dimension (BSE) is 6.88 inches, pretty close to the application?¡¥s sought after 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which might appear to be excessive, even so, the coupling size is critical to manage the bore dimension.
Step four: The SX228-6 coupling is rated to get a highest unbalanced speed of three,400 RPM, over adequate to support the application pace of one,150 RPM.
Phase five: To determine in the event the coupling will deal with the parallel misalignment, make use of the trig function of tan 1?? = offset permitted for 1 inch = 0.0174
Multiply the 0.0174 x the distance in between disc packs or ??S?¡¥ dimension through the table on 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), consequently this coupling can accommodate the parallel misalignment.
Note: It can be always proposed to try and install the coupling at roughly 20% with the allowable misalignment. For this coupling the installer ought to attempt to obtain greater than 0.020 parallel misalignment at the time of installation. This will likely make it possible for for your added misalignment that should take place since the outcome of products settle and general tools wear.