The next is actually a sample application utilised to illustrate the conventional process for picking out 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:
A company features a compressor application employing 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 by using a 7/8 inch keyway as well as the compressor features a 92mm shaft having a 25mm keyway. The shaft separation is approximately 7 inches concerning shaft ends with some means to alter the motor place. The shafts possess a parallel misalignment/offset of approximately 1/32 of an inch.
Stage one: The 1st stage is always to figure out what coupling kind will be to be picked for this application. Since the SU Form coupling only supports
a single flex plane, it could possibly only accommodate angular and axial misalignment, but not parallel misalignment. The next decision can be to search at an SX or DI Sort coupling. The 6 bolt SX Form will accommodate each parallel misalignment and the defined shaft separation. The dimension are going to be determined by the selection torque along with the shaft diameters.
Stage two: Next, calculate the application torque and apply the services aspect to determine the selection torque.The formula applied to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging within the numbers in the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Support Issue = Assortment Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Stage 3: Make use of the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, greater than adequate to manage the assortment torque calculated in stage 2. The SX202-6, on the other hand, will not help the 92mm shaft dimension. The following larger dimension coupling, the SX228-6, will help the 92mm shaft dimension and the shaft separation dimension (BSE) is six.88 inches, incredibly near to the application?¡¥s preferred seven inch separation. The SX228-6 is rated at 62,000 in-lbs which might seem to be extreme, nonetheless, the coupling dimension is critical to manage the bore size.
Phase four: The SX228-6 coupling is rated to get a maximum unbalanced velocity of 3,400 RPM, in excess of sufficient to assistance the application speed of one,150 RPM.
Stage five: To determine in the event the coupling will manage the parallel misalignment, utilize the trig perform of tan 1?? = offset allowed for 1 inch = 0.0174
Multiply the 0.0174 x the distance concerning disc packs or ??S?¡¥ dimension from the table on web page D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x 5.50 = 0.096 inches. The utmost offset for the application is 1/32 inches (0.031), therefore this coupling can accommodate the parallel misalignment.
Note: It is always proposed to endeavor to set up the coupling at roughly 20% with the allowable misalignment. For this coupling the installer really should seek to achieve better than 0.020 parallel misalignment with the time of installation. This can enable for your supplemental misalignment that should happen since the result of gear settle and common products wear.