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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.
For the lubrication of open gear drives
used in different industrial applications
such as cement and coal mills,
rotary furnaces, or where the sealing
conditions are difficult, semi-fluid
greases are often used in preference to
fluid oils. For girth gear applications
the greases are used with a splash or
spray lubrication system. The selection
of such greases influences pitting lifetime
and the load-carrying capacity of
the gears, as well as wear behavior
When trying to find a new bonding material dispense system, one manufacturer tested a series of pumps — all of which leaked due to the abrasiveness of the bonding material. The manufacturer also had been attempting to manage shot size
manually with their previous system, and was not able to keep dispense consistent. The company searched for
a system that could accurately dispense programmed shot sizes while also eliminating the leaking issues they
had experienced with previous pumps. Graco provided a Check-Mate pump with SmartWare software, and the manufacturer is now able to automatically dispense shots of bonding material as small as one ounce without leaks.
Slow speed operation of fan systems within the air handling
industry is generally performed due to two reasons: a coast
down operation is required for hot (induced draft) fans to
cool down before shutdown (often by using a turning gear),
and operational efficiency improvements can be achieved
during non-peak periods by slow speed operation using a
VFD. In either case, when these fans are supported by hydrodynamic
bearings, it is the oil film thickness developed from
the bearing-shaft interaction that limits the minimum speed
that can be maintained without causing premature wear and
bearing failure. This paper will present a brief overview of
lubrication theory and critical design parameters to achieve
slow speed operation.