When faced with a motor need, much thought & consideration is often given to the sizing & selection of the motor to ensure it is suitable for the application. But what about the coupling? Many motor applications are direct coupled and thus require some analysis for selection of the proper coupling. Of course knowing the correct bore size is a critical piece of information when selecting a coupling. But what other factors do we need to consider? Following is a list of criteria to take into account when selecting a coupling:
– Application – What is the application of the motor & coupling? Certain couplings are designed for better performance in specific types of applications.
– Torque – Have the proper torque calculations been determined?
– Shock Load/Vibration – Does the coupling need to cushion shock loads or isolate vibration?
– Misalignment – How much potential misalignment will the coupling need to tolerate? Couplings can be subject to angular or parallel misalignment as well as axial end-float.
– Temperature Range – Is heat a factor? Certain coupling components such as rubber seals and non-synthetic lubricants have a limited temperature range.
– Speed – What are the speed requirements? As the diameter of a coupling increases, its speed capability decreases as a result of centrifugal force.
– Service Factor – What are the starting load requirements?
– Locking Mechanism – How will the coupling be connected to the shaft? Shaft corrosion & scarring from a set screw style eccentric lock can be avoided with a bushing style concentric lock.
– Installation & Maintenance Costs – How easy or difficult is it to install the coupling? What are the lubrication intervals and/or other scheduled maintenance?
By thoroughly reviewing the application in question and answering these questions, one can greatly increase the likelihood of proper coupling selection and ensure many months and years of high performance & service.