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January 26, 2021

The next can be a sample application utilized to illustrate the typical method for choosing 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 features a compressor application utilizing a 225 horsepower electrical motor operating at one,150 RPM to drive a three cylinder multi stage reciprocating air compressor. The electric motor has a 3-3/8 inch shaft using a 7/8 inch keyway and the compressor has a 92mm shaft that has a 25mm keyway. The shaft separation is roughly 7 inches in between shaft ends with some potential to alter the motor location. The shafts have a parallel misalignment/offset of approximately 1/32 of an inch.
Step one: The first step is usually to identify what coupling style is to be chosen 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 subsequent option would be to seem at an SX or DI Variety coupling. The six bolt SX Form will accommodate the two parallel misalignment plus the defined shaft separation. The size will likely be determined by the choice torque and also the shaft diameters.
Stage two: Following, determine the application torque and apply the service aspect to calculate 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 during 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 Support Factor = Variety Torque
twelve,331 in-lbs x three.0 = 36,993 in-lbs
Step three: Use the SX coupling tables and note that the SX 202-6 is rated at forty,700 in-lbs, greater than adequate to deal with the variety torque calculated in step two. The SX202-6, on the other hand, won’t help the 92mm shaft dimension. The following more substantial size coupling, the SX228-6, will support the 92mm shaft size and also the shaft separation dimension (BSE) is six.88 inches, pretty close to the application?¡¥s desired 7 inch separation. The SX228-6 is rated at 62,000 in-lbs which may possibly appear to be excessive, however, the coupling dimension is necessary to deal with the bore size.
Step four: The SX228-6 coupling is rated for a maximum unbalanced velocity of 3,400 RPM, over adequate to help the application pace of one,150 RPM.
Stage five: To determine if the coupling will take care of the parallel misalignment, make use of the trig perform of tan 1?? = offset permitted for 1 inch = 0.0174
Multiply the 0.0174 x the distance concerning disc packs or ??S?¡¥ dimension through the table on page D-13, or five.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), thus this coupling can accommodate the parallel misalignment.
Note: It is constantly advisable to try to install the coupling at roughly 20% of the allowable misalignment. For this coupling the installer must try to accomplish superior than 0.020 parallel misalignment in the time of set up. This will make it possible for for your supplemental misalignment that can occur as the outcome of gear settle and basic products wear.