The following is really a sample application utilized to illustrate the standard system for selecting 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 utilizing a 225 horsepower electric motor running at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electrical motor features a 3-3/8 inch shaft using a 7/8 inch keyway and the compressor features a 92mm shaft having a 25mm keyway. The shaft separation is roughly 7 inches amongst shaft ends with some capability to modify the motor location. The shafts possess a parallel misalignment/offset of roughly 1/32 of an inch.
Phase one: The very first phase would be to identify what coupling type is usually to be selected for this application. Since the SU Type coupling only supports
a single flex plane, it may only accommodate angular and axial misalignment, but not parallel misalignment. The subsequent option can be to seem at an SX or DI Form coupling. The 6 bolt SX Type will accommodate each parallel misalignment plus the defined shaft separation. The dimension are going to be determined by the variety torque as well as shaft diameters.
Step two: Next, determine the application torque and apply the support aspect to determine the variety torque.The formula utilised to determine torque is as follows:
Application Torque ( in¡§Clb ) = ( HP x 63025 )/RPM
or Nm = ( KW x 9550)/RPM
Plugging within 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 Support Factor = Selection Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Stage 3: Utilize the SX coupling tables and note that the SX 202-6 is rated at 40,700 in-lbs, a lot more than sufficient to deal with the assortment torque calculated in stage 2. The SX202-6, on the other hand, is not going to assistance the 92mm shaft dimension. The following larger dimension coupling, the SX228-6, will support the 92mm shaft size along with the shaft separation dimension (BSE) is 6.88 inches, quite close to the application?¡¥s preferred seven inch separation. The SX228-6 is rated at 62,000 in-lbs which could appear to be excessive, on the other hand, the coupling dimension is necessary to manage the bore size.
Phase four: The SX228-6 coupling is rated for a optimum unbalanced velocity of 3,400 RPM, in excess of enough to assistance the application pace of one,150 RPM.
Phase five: To determine if the coupling will deal with the parallel misalignment, use the trig perform of tan 1?? = offset permitted for one inch = 0.0174
Multiply the 0.0174 x the distance involving disc packs or ??S?¡¥ dimension through the table on web page D-13, or five.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The maximum offset for your application is 1/32 inches (0.031), as a result this coupling can accommodate the parallel misalignment.
Note: It can be normally proposed to endeavor to install the coupling at approximately 20% in the allowable misalignment. For this coupling the installer should endeavor to realize better than 0.020 parallel misalignment on the time of set up. This will make it possible for to the supplemental misalignment that can take place since the result of gear settle and standard gear dress in.