Construction and Characteristics of a Motor Shaft

Most rotating instruments in systems across various industries rely on shafts to generate their rotational motion. One common application for shafts are in electric motors; an electric motor shaft is a centrally located cylindrical part that protrudes from the motor and housing. Operating in relation to speed and torque, the shaft functions to transfer energy from the motor to its intended use. With various factors to consider when procuring a motor shaft for your specific applications, this blog will offer an overview of the construction and characteristics of these vital part types.

Every aspect of your electric motor shaft’s design influences its performance, from material to size and much more. As such, the first thing to consider when looking to procure a motor shaft is its construction. For example, the size of the shaft has a significant impact on torque, so considering the correct material will improve reliability. Typically, motor shafts are constructed from mild steel, but alloy steels like chromium-vanadium, nickel, and nickel-chromium are preferred for high-strength applications. For example, an application with a rotation speed over 20 rpm and large torque will require high-strength parts. Nonetheless, lightweight designs remain ideal, so hollow shafts are popular choices for such motors.

Two popular materials for motor shafts are cold-rolled steel (CRS) and hot-rolled steel (HRS), both of which offer appropriate strength, toughness, and wear resistance. Cold-rolled steel is slightly more expensive than hot-rolled steel, but hot-rolled material should be sized greater than cold-rolled form because of the lack of outer diameter (OD) monitoring in the rolling procedure. Manufacturers of electric motors must evaluate whether the larger-size and lower-material-cost hot-rolled bar stock are more or less costly than cold-rolled bar stock. Hot-rolled steel is also more problematic for machining as it is more prone to deficiencies like hard and soft spots. As such, the best way to go about selecting the material of your motor shaft is to conduct trials.

Once you have determined the best material for your motor shaft, it is important to have appropriate motor shaft alignment. This term refers to ensuring that the parts of the shaft which are most likely to fail are designed accurately to perform within their acceptable limits. The better the alignment, the better a shaft will be in efficiency and the smooth transfer of energy from the motor to the driven instrument. There are three categories of misalignment to be wary of, those of which include angular misalignment, parallel misalignment, and combination misalignment.

Angular misalignment occurs when the motor is installed at an angle in relation to the driven equipment so the center of both the device and the shaft do not share a centerline. Meanwhile, parallel misalignment occurs when the two centers are on entirely separate parallel lines. Combination misalignment happens when the motor shaft suffers from both parallel misalignment and angular one simultaneously. This is the most traditional misalignment situation encountered in the system.

As misalignment can be harmful to your applications, be sure to note any extra vibrations coming from your motor and conduct annual checks of its components. Another problem to be wary of when working with electric motor shafts are circulating currents which cause unwanted electric arcing. To resolve this issue, some constructors will design the motor with an insulated bearing housing. All together, procuring a long-lasting and reliable motor shaft for the rotational movement of your applications requires consideration and trials, but we have all you need for your smooth operations at ASAP Buying.

ASAP Buying is a leading online supplier of electronic components and aircraft engine parts with unparalleled access to an ever-expanding inventory of over 2 billion new, used, obsolete, and hard-to-find parts. We encourage you to browse our database at your leisure to locate any items you wish to procure. Then, simply submit a detailed Instant Request for Quote (RFQ) form to receive a custom quote within 15 minutes or less. With our team of market professionals working around the clock, we are readily available to answer your calls and emails at all times; contact us today to get started.


March 21, 2023

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