The next is really a sample application made use of to illustrate the regular system for picking out a Disc coupling. Any resemblance to any current company?¡¥s application is neither intentional nor meant to resemble that company?¡¥s real application.
Sample Application:
A company has a compressor application making use of a 225 horsepower electric motor working at 1,150 RPM to drive a 3 cylinder multi stage reciprocating air compressor. The electrical motor features a 3-3/8 inch shaft that has a 7/8 inch keyway and the compressor has a 92mm shaft that has a 25mm keyway. The shaft separation is approximately seven inches between shaft ends with some ability to alter the motor area. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Phase one: The primary step is always to establish what coupling sort is usually to be selected for this application. Since the SU Kind coupling only supports
just one flex plane, it can only accommodate angular and axial misalignment, but not parallel misalignment. The next selection will be to search at an SX or DI Sort coupling. The six bolt SX Type will accommodate both parallel misalignment plus the defined shaft separation. The size will likely be established from the choice torque plus the shaft diameters.
Stage 2: Up coming, calculate the application torque and apply the service element to determine the assortment 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 inside the numbers through the application description:
Application Torque ( in-lbs ) =(HP x 63025)/RPM = (225 x 63025)/1150 = 12,331 in-lbs
Application Torque x Support Aspect = Variety Torque
12,331 in-lbs x three.0 = 36,993 in-lbs
Stage three: Make use of the SX coupling tables and note the SX 202-6 is rated at forty,700 in-lbs, in excess of enough to deal with the variety torque calculated in phase two. The SX202-6, however, won’t assistance the 92mm shaft dimension. The subsequent greater dimension coupling, the SX228-6, will support the 92mm shaft size and the shaft separation dimension (BSE) is six.88 inches, quite near to the application?¡¥s wanted seven inch separation. The SX228-6 is rated at 62,000 in-lbs which might seem to be extreme, having said that, the coupling size is critical to manage the bore dimension.
Stage 4: The SX228-6 coupling is rated for any optimum unbalanced speed of 3,400 RPM, a lot more than sufficient to help the application pace of 1,150 RPM.
Phase five: To find out in case the coupling will deal with the parallel misalignment, make use of 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 webpage D-13, or 5.50 inches.
The allowable parallel offset is 0.0174 x five.50 = 0.096 inches. The utmost offset to the application is 1/32 inches (0.031), for that reason this coupling can accommodate the parallel misalignment.
Note: It really is generally encouraged to attempt to set up the coupling at roughly 20% from the allowable misalignment. For this coupling the installer should make an effort to realize superior than 0.020 parallel misalignment at the time of installation. This may let for your supplemental misalignment which will come about as the outcome of tools settle and common products dress in.