If you’re an electrical engineer you know how an electric motor works; if you aren’t, it can be extremely confusing. Therefore, here’s the simplified explanation (or the “how an electric motor works for dummies” version) of how a four-pole, three-phase AC induction motor works in a car.

I need help determining the diametral pitch needed to achieve the closest center-to-center distance for 2 spur gears. The 1st gear is a 34-tooth and the 2nd gear is a 28-tooth. The center-to-center distance between the gears needs to be as close to 2 1/8" as possible.

I was invited by Tom Astrene of TLT to write a response to the July 2010 TLT article (Ref. 1). My rebuttal — “In Search of a Fatigue Limit: A Critique of ISO Standard 281:2007” — was published in Tribology and Lubrication Engineering, TLT, August 2010 edition (Ref. 10). While this article is also available online, I will attempt to summarize the essence of my response.

Pack Expo takes place November 6-9 at McCormick Place in Chicago. With 2,100 exhibitors, it’s the world’s largest most comprehensive processing and packaging trade show in 2016.

Here’s what we know about Tremont, Illinois: It’s a small village in Tazewell County, (population 2,400+), holds an annual summer turkey festival (quite popular) and the courthouse is a famous historic site where politician James Shields challenged an “up-and-coming” lawyer named Abraham Lincoln to a duel with cavalry broad swords (they showed up, but the duel never materialized). In 2016, you can add FIRST Robotics Competition World Champion to the village’s rather eccentric list of accomplishments.

Until now the estimation of rolling bearing life has been based on engineering models that consider an equivalent stress, originated beneath the contact surface, that is applied to the stressed volume of the rolling contact. Through the years, fatigue surface–originated failures, resulting from reduced lubrication or contamination, have been incorporated into the estimation of the bearing life by applying a penalty to the overall equivalent stress of the rolling contact. Due to this simplification, the accounting of some specific failure modes originated directly at the surface of the rolling contact can be challenging. In the present article, this issue is addressed by developing a general approach for rolling contact life in which the surfaceoriginated damage is explicitly formulated into the basic fatigue equations of the rolling contact. This is achieved by introducing a function to describe surface-originated failures and coupling it with the traditional, subsurface-originated fatigue risk of the rolling contact. The article presents the fundamental theory of the new model and its general behavior. The ability of the present general method to provide an account for the surface–subsurface competing fatigue mechanisms taking place in rolling bearings is discussed with reference to endurance testing data.