How often to lubricate electric motors & what type of oil to use
POST a QUESTION or COMMENT about how to troubleshoot electric motors such as air conditioning compressor motors, heating equipment burner or fan motors, swimming pool motors, water well pump motors
Electric motor lubrication schedule & oiling ports:
This article explains the typical lubrication requirement for for motors found on HVAC equipment in buildings such as air conditioners, furnace or air handler blower fans, oil burner motors, well pumps, and condensate return pumps. While some motors are permanently lubricated, others require lubrication as often as annually, depending on the motor usage level.
A simple check of the motor's data tag, explained here, can give the lubrication requirements needed to keep the motor running reliably and safely.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?
Electric Motor Lubrication Specifications & Schedules: when, how much oil, where to oil
The two approaches to lubricating the moving parts of an electric motor are:
Permanently-lubricated electric motors:
the motor has no oiling ports, has sealed lubricated bearings installed at the factory.
Watch out:this motor should not be oiled.
Doing so may damage the motor.
Duty-cycle based manually lubricated electric motors:
these motors require maintenance according to how much they are in use (their duty cycle) and will have oiling ports, usually an open tube or an openable metal cap at either end of the motor.
Here are Beckett's (1989) recommended motor oiling intervals:
Photo: a contemporary Beckett oil burner motor assembly.
Air Conditioner, Heat Pump, or Heating System Electric Motor Lubrication Schedule
Duty Cycle
Explanation of electric motor duty cycle
Lubrication Frequency (Years)
Occasional Duty Electric Motors
Motor runs less than 2 hours per day
5 years
Intermittent Duty Electric Motors
Motor runs 2-12 hours per day
2 years
Continuous Duty Electric Motors
Motor runs 12 or more hours per day
Annually
Permanently-lubricated Electric Motors
No oil ports, factory-sealed pre-lubricated bearings
Never
Notes to the table above
At ELECTRIC MOTOR DATA TAG we explain all of the information that can be found on the electric motor data tag, including the motor's lubrication requirements.
How much oil is required when lubricating an electric motor? The answer is I can't say because the quantity varies according to the motor design.
For the oil burner motor whose data tag is illustrated at the top of this page, re-oil instructions specify that each bearing is to be lubricated with 150 drops (about one teaspoon) of SAE 20 oil.
Watch out: Lubrication should be with an oil and at frequency specified by the equipment manufacturer. If you don't have this data use the table above. Lubrication typically is with SAE 20 oil, droplets or tube-fed into the motors (usually two) oiling ports.
Watch out: Do not soak the motor in oil, do not spray the motor windings with spray oils like WD40, do not try to lubricate permanently-lubricated motors that don't have an oil port.
Watch out: lack of lubrication can cause an electric motor to overheat, go off on thermal overload
Watch out: if the motor's data tag indicates that it is permanently lubricated or does not require lubrication, don't try to lubricate it - you're likely to cause damage or even an unsafe motor.
How & Where to oil an electric motor
Reader Question: where are the lubrication points for an electric motor such as the Emerson K55hxkwa-9803 ?
Can you oil a Emerson K55hxkwa-9803 - (July 23, 2014) Jeff Wilmsmeier said:
Reply:
Jeff I had trouble finding a manual for this fan motor online too - so I don't know the answer.
Look closely at the motor assembly. Oil ports will be obvious, often capped with a hinged cap or a hole facing up marked "OIL" on the steel body of the motor.
Or send us some sharp photos of all sides of the motor and we'll comment further.
Below we illustrate three electric motors, all happening to be found in heating furnace blower compartments.
In our photo above we see an electric motor that is permanently-lubricated or factory-lubricated.
There are no visible oiling points.
Demonstrated by our next photo below, oil points on a typical electric motor such as these furnace blower motors will be visible as a small metal cap that opens on a vertical tube that directs a few drops of proper lubricating oil onto the motor's bearing and shaft end (red arrow, below-right).
Other older electric motors may also have oiling points without the vertical lubricant directing tube, just a rubber or metal cap over the oil insertion point such as shown in our photo at below left (blue arrow).
Question: what weight oil should be used on a small GE electric motor?
2019/09/28 Jim said:
[What]
weight oil required for GE 1/3 hp electric motor vertical
mounted on heat pump
Reply:
Jim
Here is what GE's motor instructions say
See
Relubrication, Table 2 and Lube Nameplate for oil grade and viscosity and further instructions.
We show the GE electric motor lubrication oil table below
References for Electric Motor Lubrication Specifications
GE Vertical Motor Lubrication Table 2: Oil Viscosity
Oil Viscosity - SUS
Bearing Function & Location
Bearing Type
@ 40°C (100°F)
@ 100°C (21°F)
GE Spec
Thrust Bearing (in top end shield) 320-5013 Frame
Angular Contact Ball
150
45
D6B6A
Spherical Roller
600 or 300
70
D6B14C1
53
D6B6B
Guide Bearing (in base end shield)
For motors with oil lubrication in lower bearing
Ball
150
45
D6B6A
Notes to the table above
Source:
GE Industrial Systems VERTICAL INDUCTION MOTORS INSTALLATION INSTRUCTIONS [PDF] for High Thrust Hollow & Solid Shaft and In-Line Solid Shaft, Frames 182-5013 NEMA TYpe P Base TEFC, GEI-M1011A, retrieved 2019/09/28, original source: https://www.gepowerconversion.com/sites/gepc/files/product/GEI-M1011%20Installation%20Vertical%20High%20Thrust%20Motors.pdf
Excerpt: This manual has been written to assist the user with proper procedures when handling, installing, operating and maintaining the
equipment. All of the safety warnings and instructions in this book must be followed to prevent injury to personnel.
Watch out: For a particular motor, refer to the oil lubrication nameplate or instructions
Also see
ExxonMobil GUIDE to ELECTRIC MOTOR BEARING LUBRICATION [PDF] ExxonMobile Lubricants & Specialties, retrieved 2019/09/28 original source: https://www.hollandindustrial.com/wp-content/uploads/sites/197/2015/12/Guide-to-Electric-Motor-Lubrication-Exxon.pdf
Excerpt:
The proper lubrication of electric motor bearings is essential to maintaining them in peak operating condition and,
ultimately, in reducing unnecessary downtime.
This bulletin, for ExxonMobil customers, is intended to serve as a practical guide to the proper lubrication of electric motor bearings utilizing grease as a lubricant.
It can help you to apply ExxonMobil's years of lubrication experience with that of bearing and motor manufacturers from around the world to provide you with a guide to the proper lubrication of electric motor bearings.
Siemens INDUCTION MOTORS / GENERATORS MANUAL [PDF] Instructions for installation, operation, maintenance, for Large Frame Vertical
500, 580, 30, 36 Frames, Type CGV, CGIIV, CGZV, RGZZV, CGHS,
CGIIHS, CGZHS, RGV, FODV, AZV, HSHG, HSFOD, HSZ motors. Retrieved 2019/09/28 original source: https://www.industry.usa.siemens.com
Excerpts:
Watch out: This equipment contains hazardous voltages. Death, serious personal injury or property damage can result if safety instructions are not followed. The successful and safe operation of motors/generators is dependent upon proper handling, installation, operation and maintenance, as well as upon proper design and manufacture.
Failure to follow certain fundamental installation and maintenance requirements may lead to personal injury and the failure and loss of the motor as well as damage to other property. Only qualified personnel should work on or around this equipment after becoming thoroughly familiar with all warnings, safety notices and maintenance and repair procedures and all plant safety procedures must be observed.
U.S. MOTORS® Brand Products ELECTRIC MOTOR PRODUCT SERVICE MANUAL [PDF] retrieved 2019/09/28 original source: https://acim.nidec.com/motors/usmotors/-/media/usmotors/documents/techdocs/service/manual.ashx?la=en-us
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
Ask a Question or Search InspectApedia
Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
Note: appearance of your Comment below may be delayed:if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.
Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted. Please bookmark this page to make it easy for you to check back for our response.
[1] Beckett Oil Burners, "Burner Motor Service Facts", Beckett Corporation, Technical Information, 15 June 1989 [copy on file as PDF].
[2] N. Srinivasan, MSEE, is a senior member of IEEE with 30 years experience in the electrical industry. Mr. Srinivasan is in Vienna VA.
[3] Louis P. Babin generously contributed technical editing about the effects of doubling ampacity in an electrical circuit (September 2007)
[4] Digisnap DSA-500 snap-around digital multimeter, A.W. Sperry Instruments Inc., 2150 Joshua's Path, Suite 202, Hauppage NY 11788, Tel: 800-645-5398, Email: cat@awsperry.com, Website: www.awsperry.com
[5] Fluke Corporation, 6920 Seaway Blvd, Everett, WA 98203, USA, PO Box 9090 Everett, Washington 98206, Tel: +1(425) 347-6100, Technical support: 1(800) 44-FLUKE (1(800) 443-5853), Website: www.fluke.com,
Fluke Europe B.V,
PO Box 1186 Eindhoven, The Netherlands, Tel: +31 (0)40 2 675 200 +31 (0)40 2 675 222, Website: www.fluke.eu
Fluke India: TTL India Pvt. Ltd. (A Fluke Company), Deodhar Center, 424, Marol Maroshi Road, Andheri (E), Mumbai, 400076, Tel: 1 800 209 9110, Email: info.india@fluke.com, Website: http://www.fluke.com/fluke/inen/products/Digital-Multimeters.htm
Digital 287/289 Digital Multimeter, Users Manual, retrieved 9/5/21, original source: http://assets.fluke.com/manuals/287_289_umeng0200.pdf, [copy on file as Fluke_287_289_umeng0200.pdf]
Simpson 260® Series 6XLM Volt-Ohm-Milliammeter Instruction Manual, retrieved 9/5/2012, original source: http://www.simpsonelectric.com/uploads/File/datasheets/260-6xlm.pdf, [copy on file as Simpson_260-6xlm.pdf]
[15] Dr. Jess Aronstein, consulting engineer, Poughkeepsie NY, 1991 protune@aol.com
[16] Rex Cauldwell, master electrician and contributor to the Journal of Light ConstructionOn electrical topics
[17] New York State Central Hudson Gas and Electric Company, G&E/1-2/85 consumer safety pamphlet
[24] "Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
[25] "Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
[26] "How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
[27] "Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
[28] "Home Wiring Inspection," Roswell W. Ard, Rodale's New Shelter, July/August, 1985 p. 35-40.
[29] "Evaluating Wiring in Older Minnesota Homes," Agricultural Extension Service, University of Minnesota, St. Paul, Minnesota 55108.
[30] Jim Simmons: Personal communication, J. Simmons to Daniel Friedman, 9/19/2008. Photographs contributed to this website by Jim P. Simmons, Licensed Electrician, 360-705-4225 Mr. Electric, Licensed Master Electrician, Olympia, Washington Contact Jim P. Simmons, Licensed Master Electrician, Mr. Electric, 1320 Dayton Street SE
Olympia, WA 98501, Ph 360-705-4225, Fx 360-705-0130 mrelectricwa@gmail.com
[31] Kenneth Kruger: Original author of the sidebar on testing VOM DMM condition: Kenneth Kruger, R.A., P.E. AIA ASCE, is an ASHI
Member and ASHI Director in Cambridge, MA. He provided basis for this article penned by DJ Friedman.
[32] Paul Galow [Website galowconsulting.com ] - technical consultant on networking, LAN design, applications support. Galow Consulting Services [Website galowconsulting.com ] , 914-204-1749, email: paulgalow@galowconsulting.com
[33] LB Miller, "A simple Do-It-Yourself test fixture that will allow you to measure the DC resistance (Rm) of RC Model Electric Motors", San Marcos C, HobbyKing.com, retrieved 9/12/12, original source: http://www.rcgroups.com/forums/showthread.php?t=580151 [copy on file as Miller_Test.pdf]
[34] "Electrical Systems," A Training Manual for Home Inspectors, Alfred L. Alk, American Society of Home Inspectors (ASHI), 1987, available from ASHI. [DF NOTE: I do NOT recommend this obsolete publication, though it was cited in the original Journal article as it contains unsafe inaccuracies]
[35] "Basic Housing Inspection," US DHEW, S352.75 U48, p.144, out of print, but is available in most state libraries.
[36] Wikipedia Web: https://www.wikipedia.org/ provided background information about some topics discussed at this website provided this citation is also found in the same article along with a " retrieved on" date. NOTE: because Wikipedia entries are fluid and can be amended in real time, we cite the retrieval date of Wikipedia citations and we do not assert that the information found there is necessarily authoritative.
WikiHow: "How to Check Out an Electric Motor", retrieved 9/12/12, original source: http://www.wikihow.com/Check-an-Electric-Motor
[37] Andy Page, "The Basics of Motor Circuit Analysis", Reliable Plant, (Noria Corporation), 1328 E. 43rd Court, Tulsa, OK 74105
In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.