Angular contact bearings are less common than the standard radial ball bearings. Therefore, it is easy to miss important characteristics that impact performance.

Vertical motors differ from horizontal motors in numerous ways, yet some view them as “just a horizontal motor turned on end.” The obvious differences are the (usually) thrust bearings, with arrangements varying from single- to three-thrust bearings with different orientations suited for specific load, rpm and applications. Less obvious differences are in the ventilation arrangements, shaft stiffness, degrees of protection and runout tolerances. This recording will cover those topics.

This article looks at the factors that go into determining how often a motor should be lubricated and how much lubricant they should recieve.

Las consideraciones para la cantidad y la frecuencia de lubricación de los rodamientos de motores eléctricos ( y generadores) incluyen lo siguiente:

• ¿El lubricante es aceite o grasa?
• ¿El tipo de rodamiento es un cojinete de deslizamiento o un rodamiento de bolas o rodillos?
• Si es un rodamiento de bolas ¿Tiene sellos, obturaciones o es abierto? En este artículo trataremos todo lo anterior dividiéndolo en las siguientes categorías:
• Cantidad de grasa y frecuencia de lubricación para rodamientos de bolas y rodillos (rodamientos de elementos rodantes).
• Frecuencia de lubricación y nivel de aceite (relacionado con la can- tidad) para rodamientos de bolas y rodillos.
• Frecuencia de lubricación y nivel de aceite (relacionado con la cantidad) para cojinetes de deslizamiento.

Dado que la lubricación con grasa de cojinetes de deslizamiento es muy rara, este tema no se incluye en este artículo. Además, ya que los rodamientos sellados no se pueden relubricar, este tema tampoco está incluido.

Considerations for lubrication frequency and quantity for electric motors (and generators) include the following:

• Is the lubricant grease or oil?
• Is the bearing type sleeve, ball or roller?
• If it is a ball bearing, is the enclosure open, shielded or sealed?

This article addresses the above by breaking them down into the following categories:

• Grease lubrication frequency and quantity for ball and roller (rolling element) bearings.
• Oil lubrication frequency and level (relates to quantity) for ball and roller bearings.
• Oil lubrication frequency and level (relates to quantity) for sleeve bearings.

This presentation covers:

• Shaft material and specs
• Shaft coupling types
• Machining for shafts
• Bronze, plastic, graphite and cutlass bearing options
• Bearing clearance concerns and reference data 
• Bearing housing fits

Two case histories point out the need for caution when working with metal sprayed shafts:

• Example 1: When measuring the bearing fit shaft size, the micrometer didn’t feel right; mushy, not solid, although the journal was very close to the specified size. After using two micrometers to experiment with one of these frosted fits, it was discovered that the measurement on one micrometer changed when tightening down the other micrometer and vice versa.
• Example 2: The bearing journals on a large armature began to fail while the armature was coming up to speed in balance stand.

Bearing construction is a key difference between vertical motors and horizontal motors that are mounted vertically. Vertical motors typically drive pumps using thrust bearings. Horizontal motors rarely have those types of bearings. Understanding relevant construction and configuration factors is crucial when confronting lubrication-related issues that can be associated with vertical-motor bearings.

Electrical bearing damage has become a very common issue in electric motors. This is not a new problem, but awareness has put the spotlight on this important reliability factor and industry has stepped up to deal with it.

Rolling-element bearing construction has become a very precise and exacting process. Studies have shown that more than one-half of motors that come to service centers are because of worn out or failed bearings. This is understandable since this component is subject to wear and sometimes abuse. Bearing manufacturers are called upon to improve the quality and reliability of their product to increase the time in service before it becomes necessary to replace the bearings. Proper application and maintenance of the bearing is also a key to improved reliability. This article looks at some of the components used to better understand what applications can be accommodated.