The following is actually a sample application utilised to illustrate the common course of action for selecting 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:
An organization has a compressor application making use of a 225 horsepower electrical motor working at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor has a 3-3/8 inch shaft having a 7/8 inch keyway as well as the compressor has a 92mm shaft having a 25mm keyway. The shaft separation is roughly seven inches between shaft ends with some ability to modify the motor place. The shafts have a parallel misalignment/offset of roughly 1/32 of an inch.
Stage 1: The primary phase is always to figure out what coupling variety is always to be selected 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 next choice can be to seem at an SX or DI Type coupling. The six bolt SX Style will accommodate each parallel misalignment and the defined shaft separation. The size is going to be determined by the selection torque along with the shaft diameters.
Stage two: Following, determine the application torque and apply the support component to calculate the choice 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 from the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Service Issue = Selection Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Step 3: Use the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, over adequate to manage the choice torque calculated in step 2. The SX202-6, having said that, won’t support the 92mm shaft dimension. The following greater size coupling, the SX228-6, will help the 92mm shaft dimension and the shaft separation dimension (BSE) is six.88 inches, incredibly close to the application?¡¥s sought after seven inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly appear to be extreme, even so, the coupling dimension is critical to handle the bore dimension.
Step 4: The SX228-6 coupling is rated to get a optimum unbalanced pace of 3,400 RPM, greater than ample to help the application pace of one,150 RPM.
Phase five: To determine in case the coupling will handle the parallel misalignment, use the trig function of tan 1?? = offset allowed for 1 inch = 0.0174
Multiply the 0.0174 x the distance involving disc packs or ??S?¡¥ dimension from the table on page D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The maximum offset for the application is 1/32 inches (0.031), consequently this coupling can accommodate the parallel misalignment.
Note: It can be always advised to attempt to install the coupling at approximately 20% of your allowable misalignment. For this coupling the installer should really seek to reach superior than 0.020 parallel misalignment on the time of set up. This may enable to the more misalignment that should come about since the outcome of tools settle and common equipment dress in.