Efficient Plant April 2018 - 18

feature | maintenance solutions

Fig. 3. Angular-contact ball bearings

Vertical and
horizontal motors
are different animals,
with different
maintenance issues.
Fig. 4. Spherical roller bearing

thrust classifications do not apply.)
Angular-contact ball bearings
are the most common types of
thrust bearings. A single bearing
is used for normal thrust loads;
two bearings in tandem
(Fig. 3) for 175% of normal
thrust (placing two bearings
in tandem does not double the
thrust capacity); and a stack of
three bearings for 250% of normal
thrust (see table on p. 17). Stacks
of as many as five bearings have been
reported.
Spherical roller bearings (Fig. 4) are
used when even higher thrust loads are
applied, such as in very deep wells where
the weight of the water column, the pump
shaft, the impeller, and the force of moving
the water can be several thousand pounds.
Spherical roller bearings can handle 300%
to 500% of normal thrust load.
A hydrodynamic bearing, also known as
a tilting-pad, plate, or Kingsbury bearing
(Fig. 5), is capable of extremely high thrust
loads and very long life. As with sleeve
bearings in horizontal motors, there is theoretically no wear on the plates because
the load is carried on an oil film that
separates the moving parts.

SPECIAL THRUST CASE
Occasionally, pump designs
will exceed the momentary
up-thrust limits (more common on two-pole [3,000/3,600
rpm] applications), and the
guide bearing cannot accommodate that thrust for the necessary duration. In such cases,
the upper bearings are arranged
face-to-face or back-to-back. Note
that with back-to-back bearings thrust
transmission is in opposite directions (see
arrows in Fig. 6, p. 20). This configuration

18

| EFFICIENTPLANTMAG.COM

also requires additional parts. A holddown ring, for example, must be located
on the outer race of the upper bearing and
fastened to the upper bracket to prevent the
up-thrust from lifting the bearings from
the bearing bore. A nut or a spiral-lock
snap ring must also be applied to the bearing carrier below the lower bearing inner
race to prevent the up-thrust from pushing
the bearings off the mount.

OIL-LEAK ISSUES
Vertical motors are unique in their ability
to carry external thrust. The thrust bearings that make this possible require care in
assembly and application for optimum service and performance. Unfortunately, those
bearings also put vertical motors at risk
for several lubrication-related problems.
That's because many of them are lubricated
with oil-bath reservoirs, which, in turn,
can develop leaks that may be difficult to
diagnose and correct. Causes of oil leaks
include loose stand tubes (the part that defines the inner boundary of the reservoir),
moving the motor with oil in the reservoir,
over-filling the reservoir, water intrusion,
machine-tool marks, and foaming. The
following tips can help ensure leak-free
performance:
 When disassembling a leaky vertical motor, carefully inspect the space
between the shaft and the inside of the
stand tube. Oil observed in this area
narrows the scope of the investigation,
because the oil must go over the stand
tube to get there. Leaks of this type are
often caused by overfilling the reservoir
or by the sloshing action that results
from moving the motor with oil in the
reservoir. If the motor base is out of
level by more than a degree, the oil-level
indication in the sight glass will be inaccurate and could cause the oil to be above
the stand tube.

APRIL 2018


http://www.EFFICIENTPLANTMAG.COM

Table of Contents for the Digital Edition of Efficient Plant April 2018

Editorial
Implementations
What's Wrong With My Bolts?
Understand Vertical Motor Bearings
Bourbon Boom Drives Distillery Expansion
Lubricant Myths That Can Cost You
IIoT
SAP: When To Update SAP Master Data
Give Your Chain A 'Hand'
Why Do Hackers Hack?
Why Compressor Size Matters
Equipment-Rental Considerations
On The Floor
Microgrids Are On The Rise
Solution Focus
Products
Index
Showcase
Seeking Reliability
Efficient Plant April 2018 - Cover1
Efficient Plant April 2018 - Cover2
Efficient Plant April 2018 - 1
Efficient Plant April 2018 - 2
Efficient Plant April 2018 - 3
Efficient Plant April 2018 - 4
Efficient Plant April 2018 - 5
Efficient Plant April 2018 - Editorial
Efficient Plant April 2018 - 7
Efficient Plant April 2018 - Implementations
Efficient Plant April 2018 - 9
Efficient Plant April 2018 - What's Wrong With My Bolts?
Efficient Plant April 2018 - 11
Efficient Plant April 2018 - 12
Efficient Plant April 2018 - 13
Efficient Plant April 2018 - 14
Efficient Plant April 2018 - 15
Efficient Plant April 2018 - Understand Vertical Motor Bearings
Efficient Plant April 2018 - 19
Efficient Plant April 2018 - 20
Efficient Plant April 2018 - Bourbon Boom Drives Distillery Expansion
Efficient Plant April 2018 - 22
Efficient Plant April 2018 - 17
Efficient Plant April 2018 - 18
Efficient Plant April 2018 - 19
Efficient Plant April 2018 - 20
Efficient Plant April 2018 - Bourbon Boom Drives Distillery Expansion
Efficient Plant April 2018 - 22
Efficient Plant April 2018 - 23
Efficient Plant April 2018 - 24
Efficient Plant April 2018 - Lubricant Myths That Can Cost You
Efficient Plant April 2018 - 26
Efficient Plant April 2018 - 27
Efficient Plant April 2018 - 28
Efficient Plant April 2018 - IIoT
Efficient Plant April 2018 - SAP: When To Update SAP Master Data
Efficient Plant April 2018 - Give Your Chain A 'Hand'
Efficient Plant April 2018 - Why Do Hackers Hack?
Efficient Plant April 2018 - Why Compressor Size Matters
Efficient Plant April 2018 - Equipment-Rental Considerations
Efficient Plant April 2018 - On The Floor
Efficient Plant April 2018 - 36
Efficient Plant April 2018 - Solution Focus
Efficient Plant April 2018 - 38
Efficient Plant April 2018 - 39
Efficient Plant April 2018 - 40
Efficient Plant April 2018 - Products
Efficient Plant April 2018 - 42
Efficient Plant April 2018 - 43
Efficient Plant April 2018 - 44
Efficient Plant April 2018 - 45
Efficient Plant April 2018 - Index
Efficient Plant April 2018 - Showcase
Efficient Plant April 2018 - Seeking Reliability
Efficient Plant April 2018 - Cover3
Efficient Plant April 2018 - Cover4
https://www.nxtbook.com/atp/MaintenanceTechnology/epjulyaug2020
https://www.nxtbook.com/atp/MaintenanceTechnology/epjune2020
https://www.nxtbook.com/atp/MaintenanceTechnology/epmay2020
https://www.nxtbook.com/atp/MaintenanceTechnology/epapril2020
https://www.nxtbook.com/atp/MaintenanceTechnology/epmarch2020
https://www.nxtbook.com/atp/MaintenanceTechnology/epfeb2020
https://www.nxtbook.com/atp/MaintenanceTechnology/epjan2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epnovdec2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epseptoct2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epmay2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epapril2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epmarch2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epfebruary2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epjanuary2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epdecember2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epnovember2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epoctober2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epseptember2019
https://www.nxtbook.com/atp/MaintenanceTechnology/epaugust2018
https://www.nxtbook.com/atp/MaintenanceTechnology/0818schneider
https://www.nxtbook.com/atp/MaintenanceTechnology/epjuly2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epjune2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epmay2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epapril2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epmarch2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epfebruary2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epjanuary2018
https://www.nxtbook.com/atp/MaintenanceTechnology/epdecember2017
https://www.nxtbook.com/atp/MaintenanceTechnology/epnovember2017
https://www.nxtbook.com/atp/MaintenanceTechnology/epoctober2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtsept2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtaugust2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtjuly2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtjune2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtmay2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtapril2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtmarch2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtfebruary2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtjanuary2017
https://www.nxtbook.com/atp/MaintenanceTechnology/mtdecember2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtnovember2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtoctober2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtseptember2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtaugust2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtjuly2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtjune2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtmay2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtapril2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtmarch2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtfebruary2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtjanuary2016
https://www.nxtbook.com/atp/MaintenanceTechnology/mtdecember2015
https://www.nxtbook.com/atp/MaintenanceTechnology/mtnovember2015
https://www.nxtbook.com/atp/MaintenanceTechnology/mtoctober2015
https://www.nxtbook.com/atp/MaintenanceTechnology/mtseptember2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTAugust2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTJuly2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTJune2015
https://www.nxtbook.com/atp/MaintenanceTechnology/M
https://www.nxtbook.com/atp/MaintenanceTechnology/0415endress
https://www.nxtbook.com/atp/MaintenanceTechnology/MTApril2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTMarch2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTFebruary2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTJanuary2015
https://www.nxtbook.com/atp/MaintenanceTechnology/MTDecember2014
https://www.nxtbook.com/atp/MaintenanceTechnology/MTNovember2014
https://www.nxtbook.com/atp/MaintenanceTechnology/MTOctober2014
https://www.nxtbook.com/atp/MaintenanceTechnology/MTSeptember2014
https://www.nxtbook.com/atp/MaintenanceTechnology/MTAugust2014
https://www.nxtbook.com/atp/MaintenanceTechnology/MTJuly2014
https://www.nxtbookmedia.com