Electric Motors
Importance of proper lubrication in electric motors
> Electric motors represent 25% of all rotating equipment in a typical plant
> Up to 75% of motor failures are bearing related
> It is estimated that 90-95% of all bearing failures are premature
> Motor failure can lead to costly downtime
Electric Motors Introduction
Our experience shows, that electric motors are the most neglected asset in the area of preventive maintenance.
Reasons:
> Limited know-how about individual motor types
> Limited know-how about the different bearings and correct relubrication
Better electric motor lubrication results in higher availability, efficiency and a drastic reduction of total
operating costs.
Industries all over the world are putting more emphasis on the topic of lubrication. perma is seeing a
rapid increase in the number of lubrication systems ordered for electric motor bearings. However, most
electric motors are still lubricated manually with the motor shut down.
Common Electric Motor Lubrication concerns and resolutions
Concerns / Challenges
Resolution
Over / Under lubrication
Selection matrix tool to prescribe the precise dosing and intervals
Cross contamination of incompatible lubricants
Closed loop system with visible markings verifying lubricant fill
Choosing the right lubricant
Electric Motors require lubricants with specific characteristics.
Consult your motor OEM manuals or your lubricant supplier
Safety - It is generally recommended that bearings are
lubricated while motors are running exposing maintenance
personnel to possible danger incidents
Automatically lubricated, eliminating danger risks
Hidden bearings. Unlike most applications, bearings cannot
be seen
Allows for precise lubrication and eliminates over greasing
Lack of education and competency on proper methods
and practice
Comprehensive playbook on installation protocol and procedure
To eliminate the possibility of excess lubricant being forced
in motor windings there must be a known exit point for
grease injected into bearings
Use of grease relief valves or drain cups
> Re-lubrication, why?
1.Lubricant oxidation causes lubricant quality to deteriorate
2. Consumption of lubricant caused by leaks and evaporation
3. Lubricant is washed out at the lubrication point
4. Lubricant is spun off by moving parts and must be replaced
regularly for proper bearing lubrication.
Lubrication assessment criteria
For electric motor lubrication the following factors are generally assessed in order to develop the lubrication solution:
> Motor manufacturer‘s recommendations
> Characteristics of proposed lubricant
> Motor speed> Historical lubrication practices
> Grease trap / escape port design, access and condition
> Duty cycle
> Bearing types> Motor orientation (vertical or horizontal)
> Service conditions - refer to separate perma Electric Motor
Selection Matrix
Reading the motor faceplate
Gather the following data off the motor faceplate and refer to separate perma Electric Motor Selection Matrix:
üFrame Size
üRPM
üBearing#
The Yellow highlights show
example locations of where
to find the above information
on the motor faceplate
Using this information will help
determine the proper size lubricator and discharge period.
Certain motor manufacturers
may use a bearing code rather
than the actual bearing number.
Please consult the seperate
perma Electric Motor Selection
Matrix for information.
Example of motor
face plate location
on an electric motor. Shown with
perma STAR VARIO 120cc units,
direct mount.
Motor orientation can affect lubrication requirements
> It is common to double the grease rate (halve the re-lubrication period) when motors are installed in
a vertical orientation
> Vertical shafts / bearings have poorer grease retention and poorer distribution of grease
>Application Overview: Orientation, Bearing Types and Solutions
Confirm and understand bearing types
> Smaller motors usually have deep groove ball bearings at both ends
> Medium to larger motors usually have a cylindrical roller bearing at the DRIVE End (DE)
and a deep groove ball bearing at the NON-DRIVE End
Deep groove
ball bearing
> Cylindrical roller bearings have a line of contact between the rolling elements and the races
> Deep groove ball bearings have a point contact between the rolling elements and the races
> Grease service life is shorter in “line contact“ bearings than in “point contact“ bearings.
This is because bearings with line contact apply more stress to grease. Therefore line contact
bearings require a higher re-lubrication rate
Cylindrical
roller
bearing
> Lubricator settings are generally selected based on the requirements of the DE bearing
Relief Valve and Drain Cups
Typical Grease Traps & Escape
> It is highly recommended, and best practice, that Electric
Motors be equipped with an escape route for excess grease
that may accumulate in the grease cavity
> Grease escape point and
collection traps vary greatly and
allow for an escape route for any
excess lubricant
> Use of perma single-point lubricators can greatly reduce
the risk of this occurring, but use of a relief valve or drain
cup is still recommended
> Grease collection traps must
be periodically serviced to prevent overfilling
> Free purging bearing designs
> Drain cups (shown below in 1 oz and 2 oz sizes) are an
ideal solution to this issue as they are reusable and in no way
mechanically restrict the excess grease flow
> Spring-loaded relief valves (B-500; shown below) are an
option where space and access limitations make the use of
drain cups impractical
can freely receive and expel
grease allowing adequate fresh
grease to be supplied to achieve
maximum bearing life
Grease Inlet
Shown with attached
FLEX 125
B-500
1/8“ MNPT (5 lbs)
Relief Valve
Drain
Shown with attached
1 oz Drain Cup Kit
B-450
1/4“ MNPT x 1/8“
FNPT Bushing
B-475-KIT
1 oz Drain Cup
Kit includes P-111 Pipe Nipple
(attached) and B-450 Bushing
B-485-KIT
2 oz Drain Cup
Kit includes P-111 Pipe Nipple
(attached) and B-450 Bushing
>Solutions
perma lubrication systems for electric motors
perma products are used on electric motors all over the world.
They guarantee reliable, automatic re-lubrication of motor
bearings and seals.
perma STAR VARIO
Single-point lubrication systems perma STAR VARIO is available in three different sizes (60 cm3, 120 cm3 or 250 cm3). They are recommended for the lubrication of different types of bearings requiring different lubricant amounts. perma
STAR VARIO operates fully automatic, independent of temperature. The desired
discharge period and LC size can easily be selected with the push button and are
visible on the display. The current operating status is indicated on the display and
via the all around LED signal lights (red/green), which are visible from a distance.
>Installation and Mounting Decision Making
perma Single Point Lubricators can be mounted either directly to an electric motor using our wide options of accessories or when needed due to access and conditions can be remote mounted. To determine best mounting options
the following questions should be considered.
Remote or Direct?
Answer
1. Are there restrictions or obstructions that limit safe and ready
access to the lubrication points?
2. Is there limited access to motor while it is in operation?
3. Is there excessive vibration directly at lubrication point?
4. Does the ambient temperature at grease inlet exceed limits for
the lubrication system?
If yes to any, remote mounting with tube
connection would be the best option.
Remote mounting
Installation examples
Main equipment: Electric motor with remote mount
1 perma STAR VARIO 120cc per lubrication point
Main equipment: Electric motor with direct mount
1 perma STAR VARIO 60cc per lubrication point
Determining Mounting Requirements
What is thread size of lubrication point? A vast majority of electric motors have 1/8“ NPT threading
at grease inlet. There are some exceptions IE: Metric threads. (All Lubricators are ¼” MNPT and
require either an adaptor or support)
If direct mounting are there any obstructions which would require use of angled fittings and/or
extensions?
>Direct Mounting on Electric Motors
Below are accessories that are commonly used in direct mounting. Reducers, bushings and adaptors are used to adapt from motor grease inlets threading to the lubricator thread. Angles can be
used when there are obstructions that do not allow for direct straight mounting to grease inlets.
Nipples can be used in conjunction with elbows to avoid obstructions or in cases where the grease
inlet is recessed below motor cowling or housing.
A-514
Reducer M8x1o x G1/4i
A-518
Reducer M10x1o x G1/4i
B-101
Adapter 1/4“FNPT x 1/4-28
MNPT, Straight
B-400
1/4“ NPT Coupler Pipe Fitting,
Black
B-402
1/4“ NPT x 2“ Pipe Nipple,
Black
B-404
1/4“ NPT x 4“ Pipe Nipple,
Black
B-406
1/4“ NPT x 6“ Pipe Nipple,
Black
B-410
1/4“ NPT - 45° Elbow, Black
B-420
1/4“ NPT - 90° Elbow, Black
B-450
1/4“ NPT x 1/8“ NPT Bushing
P-112
1/8“ NPT Coupler
P-113
1/8“ NPT x 2“ Pipe Nipple
P-114
1/8“ NPT x 4“ Pipe Nipple
P-115
1/8“ NPT - 90° Elbow
P-116
1/4“ NPT x 1/8“ NPT Ball Reducer
P-117
1/8“ NPT Street - 45° Elbow
>Remote Mounting Kits
perma has developed specialty
remote mounting brackets and
kits designed specifically for use
with the lubricators.
>
C-Bracket Mounting Kits
Double Unit
Below are samples of commonly
used kits on electric motors.
STANDARD DUTY
Assembly Remote KIT
Double Unit
A-757
HEAVY DUTY
or
Part no.
C-Bracket SD Kit with 6 ft. tubing
A-757ASSYSD06
C-Bracket SD Kit with 12 ft. tubing*
A-757ASSYSD12
Assembly Remote KIT
Double Unit
A-757
* NOT for use with electrochemical lubricators
Part no.
C-Bracket HD Kit with 6 ft. tubing
A-757ASSYHD06
C-Bracket HD Kit with 12 ft. tubing*
A-757ASSYHD12
A
A
B
B
A
C
B
A
C
Number of included accessories depends
on unit size of bracket.
e.g.
A-757 = 2 times each part below
A. B-623
3/8"T x 1/4"MNPT Tube Connector
B. B-640
3/8" OD Nylon Tubing, Blue
C
B-421 included
optional, use
only if needed
D
E
C. B-100
1/4" FNPT x 1/8" MNPT Reducing Adapter
Standard Duty kits are designed for use where ambient conditions are not harsh and there is no
need for the manual purge valve option. The Nylon tubing is easily field cut to desired length and
the quick connect fittings make for simple and fast connections.
Kits do not come pre-assembled. All components are shipped loose.
Tubing/Hosing is field cut to shortest usable length and field
assembly is required.
C
E
Number of included accessories depends
on unit size of bracket.
e.g.
A-757 = 2 times each part below
C
Heavy Duty Kits are designed for more industrial conditions and harsher environments and
include the manual purge valve. Due to it’s higher pressure rating the B-650 hose used in the
Heavy Duty kits is more suitable for use when incorporating the manual purge valve.
D
A. B-401
Pipe Nipple -1/4"NPT Close, Black
B. B-550
Manual Purge KIT
C. B-825
1/4"MNPT x 3/8" swivel hose fitting
D. B-650
3/8 socket less hose
E. B-100
1/4" FNPT x 1/8" MNPT Reducing
Adapter
perma automatic lubrication systems we meet your needs:
> 24 hour operation
> Simple installation
> Easy, tool-free exchange
> Requires little mounting space
> Tough systems – either battery operated or machine
controlled
>Customized supply of fresh lubricants to lubrication points
perma is the most trusted partner
worldwide for all industries:
– Global market leader for automatic single-point lubrication systems
– Largest product range in the market
– Many well-known satisfied customers
–Field-tested accessories for every perma lubrication system
– Product training, expert advice and consultation
(please contact your local supplier)
Do you have any questions about perma
products for electric motors?
Please visit our website or contact your
local supplier. We will gladly send you our
extensive catalog for more detailed
information.
Electric motor manufacturers generally recommend bearings to be relubricated while motors are running. But, motors are often located in
dangerous and difficult to access places.
> Work-place safety cannot be guaranteed
> High risk of accidents
perma USA
2129 Center Park Dr.
Charlotte, NC 28217
800-997-3762
www.permausa.com