With that in mind, here’s a quick, step-by-step guide to help with greasing electric motor bearings:
- Install the grease cartridge in your grease gun, remove the grease plug, if accessible, and check that the relief fitting moves freely.
- If the motor is stopped, remove any hardened grease from the plug area.
- Wipe around grease fitting with clean rag, and pump and discard a single application of grease.
How do you lubricate a bearing on an electric motor?
Electric Motor Bearing Lubrication Procedure. Slowly add grease to minimize excessive pressure buildup in the grease cavity. Watch for grease coming out the relief port. If excessive amounts of grease are pumped into the motor and the old, used grease is not being purged, stop and check for hardened grease blocking the relief passage.
What is Grease Grease for bearings?
Grease is the lifeblood of these bearings because it provides an oil film that prevents the harsh metal-to-metal contact between the rotating element and races. Bearing troubles account for 50 to 65 percent of all electric motor failures, and poor lubrication practices account for most of these bearing troubles.
What is the purpose of Grease in electric motors?
Most electric motors are designed with grease-lubricated, antifriction, rolling-element bearings. Grease is the lifeblood of these bearings because it provides an oil film that prevents the harsh metal-to-metal contact between the rotating element and races.
How do you use a grease gun to clean a bearing?
Ensure the grease gun contains the appropriate lubricant. Clean the areas around the relief and fill fittings. Remove the grease relief valve or drain plug. Grease the bearing with a calculated amount of grease. Slowly add grease to minimize excessive pressure buildup in the grease cavity. Watch for grease coming out the relief port.
How do you lubricate electric motor bearings?
Electric Motor Bearing Lubrication ProcedureEnsure the grease gun contains the appropriate lubricant.Clean the areas around the relief and fill fittings.Remove the grease relief valve or drain plug.Grease the bearing with a calculated amount of grease. ... Watch for grease coming out the relief port.More items...
What is the most popular way to grease an electric motor bearing?
A NLGI 2 grade grease is the most commonly used in electric motor applications. ASTM D 3336 oxidation life. require a grease with an EP additive. Dropping Point: The dropping point gives an indication of the temperature at which the grease will melt or the oil will separate from the thickener.
How often do you grease electric motor bearings?
Using the chart and the formula, the bearing only needs 8 grams of grease every 10,000 hours. If your grease gun delivers around 1.35 grams per stroke, that means the bearing needs 6 strokes every 13 months; you could average it out to a stroke every 8 weeks or so.
Should electric motors be greased while running?
Care must be taken to follow the simple rule of 1-2 seconds between grease gun strokes and to grease while the motor is running. NEVER use an electric grease gun to grease an electric motor. A disadvantage of shielded bearings is an increase in friction and temperature of the bearing.
What can I use to lubricate an electric motor?
Whenever you have to lubricate an electric pump, bench grinder or other electric motor, don't pull just any oil off the shelf. Instead, pick up electric motor oil, like 3-In-One electric motor oil (about $3 at amazon). Don't use automotive motor oil! It's too “thin” for electric motors.
Is Lithium Grease good for motor bearings?
Lubrication plays a vital role in maintaining the life and effectiveness of bearings, and also protects them from corrosion and overheating. A good lithium lubricant should provide a stable barrier between each of the metal parts and protect against moisture over a range of temperatures.
Can you over grease a motor bearing?
Too much grease volume (overgreasing) in a bearing cavity will cause the rotating bearing elements to begin churning the grease, pushing it out of the way, resulting in energy loss and rising temperatures.
Can you use lithium grease on electric motors?
0:402:09Shell Lubricants - Electric Motor Grease - YouTubeYouTubeStart of suggested clipEnd of suggested clipThe right grease. And the right greasing method common greasing intervals for electric motors areMoreThe right grease. And the right greasing method common greasing intervals for electric motors are once a year or once every six months over greasing an electric motor can be detrimental electric
What grease is best for bearings?
Editor's Choice: Valvoline Full Synthetic Grease. ... Lucas Oil X-Tra Heavy Duty Grease. ... Lucas Oil Red 'N' Tacky Grease. ... Mag 1 High-Temp Wheel Bearing Grease. ... Mobil 1 Synthetic Grease. ... Timken Premium Red Wheel Bearing Grease. ... Sta-Lube New Generation Wheel Bearing Grease.More items...•
Where do I grease my electric motor?
2:404:33Mobil Grease How To Workshop: Electric Motors - YouTubeYouTubeStart of suggested clipEnd of suggested clipRemember that a burnin should never be more than two-thirds fall leaving one-third airspace to allowMoreRemember that a burnin should never be more than two-thirds fall leaving one-third airspace to allow for optimal operation. The base oil used in electric motor greases can be mineral or synthetic.
Can you spray wd40 on an electric motor?
Yes, WD-40 is safe to use on electronics. It is used frequently to dry out auto ignition systems as it it non-conductive, displaces water, and lubricates the parts without getting sticky.
Can you use silicone spray on electric motors?
DO NOT USE SILICONE SPRAY ON ELECTRICAL CONNECTIONS, SWITCHES, RELAYS, ETC. There have been numerous reports that silicone spray can cause contact problems in switches, noted in multiple posts regarding automotive problems.
Which grease used in motor bearing?
Generally, NLGI 2 grade greases are used in electric motor applications involving horizontal shaft configurations, while NLGI 3 grade greases may be more appropriate for motors supporting vertical shaft configurations. Oxidation resistance: Electric motor greases should have outstanding resistance to oxidation.
Which grease is best for bearings?
Lithium based greases are very popular as bearing grease due to their water resistance and performance characteristics in both high and low temperatures. Greases comprised of synthetic lubricating fluids perform well in extreme low and high temperature ranges.
How do you grease bearings?
2:185:50HOW-TO Grease A Sealed Bearing - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo for today I'll be using this white grease and all you want to do is pack it into the bearings.MoreSo for today I'll be using this white grease and all you want to do is pack it into the bearings. You want to push down so the grease reaches both sides of the ball bearings inside.
Why use polyurea grease in electric motors?
The new grease helps bearings run cooler and last longer, increases motor efficiency by decreasing drag, and offers excellent mechanical stability for a long service life – even in high-moisture environments.
How to grease a motor?
The general procedure for greasing is as follows: 1. Lock and tag out the electric motor. 2. Wipe grease from the pressure fitting, clean dirt, debris and paint around the grease relief plug. This prevents foreign objects from entering the grease cavity. 3.
How does grease enter a bearing?
In the type of bearing that we are discussing, the grease enters the bearing housing. Some grease comes into contact with the bearing surfaces. When the motor is restarted, this excess grease is ejected from the bearing. The temperature may briefly rise, then fall, once grease has passed through the bearing. The shear stresses and temperature reduce the viscosity of the grease, allowing it to flow.
What Happens When The Bearing Is Greased With The Motor Running?
The ‘soap,' or grease medium, acts as a suspension in the oil, although grease is normally represented as a base with an oil suspension. This becomes an important issue in the physical world of hydrodynamics.
What happens when grease comes into contact with the shaft?
Grease that comes into contact with the shaft, bearing cap opening or housing opening (usually less than 0.010 inches) becomes pumped through the openings due to Couetti Flow. This process is the result of a turning cylinder (motor shaft) with a close, stationary, cyclinder (shaft openings) and an incompressible fluid. The excess grease is literally pumped into the motor housing.
What happens when you add grease to a ball bearing?
When too much grease is added, the grease is compressed between the bearing surfaces, increasing pressure and resulting with heat.
What happens to grease when temperature drops?
Once the temperature drops, the grease is no longer within the bearing surfaces and oil from the grease provides lubrication. The increase in temperature causes a reduction in grease viscosity, allowing it to flow freely, albeit slowly, and excess grease is rejected through the grease plug (grease out).
Why does grease increase the temperature of a bearing?
Some of the grease flows through the operating surfaces of the bearing, causing stress. The reduction of clearances causes an increase in friction within the bearings. This will cause the bearing temperature to increase as the bearing surfaces reject the grease medium.
How much grease should I soften for electric motors?
An electric motor bearing grease should soften no more than 1 to 1.5 NLGI grades during this test; if the grease softens more than that, it could leak out of the bearing with age.
Why use grease on motors?
Reduce friction and wear. Protect bearings against corrosion. Act as a seal to prevent entry of contaminants. Grease is frequently used to lubricate electric motor bearings because of its simplicity of application and unique characteristics.
What is the consistency of grease?
Consistency: A grease’s consistency or firmness is stated in terms of its National Lubricating Grease Institute (NLGI) grade, which ranges from 000 to 6. Generally, NLGI 2 grade greases are used in electric motor applications involving horizontal shaft configurations, while NLGI 3 grade greases may be more appropriate for motors supporting vertical shaft configurations.
What is the dropping point of grease?
Dropping point: The dropping point is an indication of the temperature at which the grease will melt or the oil will separate from the thickener. A grease with a high dropping point is desirable, given the high temperatures reached during electric motor bearing operations.
Is anti wear grease recommended?
Anti-wear: Unless a motor is mounted so there is a thrust load on the bearings, it is advisable to choose a grease that does not have extreme pressure additives. These additives can shorten the life of the grease and are not recommended for use where they are not required.
How long does grease last in a bearing?
The small quantity will be reworked more often than an equal portion of the large quantity and will not benefit from reserve capacity (including more oil and additives). Under moderate conditions, however, a small quantity of grease in a factory lubricated sealed or shielded bearing may last a long time, perhaps several years.
Why does grease deteriorate?
All greases deteriorate at some rate, even under moderate operating conditions. The principal causes are oxidation, excessive oil bleeding, and mechanical working. At high temperatures, oil evaporation may also be a factor. Oxidation eventually increases the oil viscosity and hardens the soap. Some oil bleeding is desirable, but too much reduces the ability of the grease to maintain an effective lubrication film. Mechanical working, or shearing, may change grease properties such as consistency, making the grease less suited to the application. Excessive oil evaporation may harden the grease. Deterioration often ends in hard, dry, deposits that can neither lubricate bearings nor protect them against contaminants.
What happens when grease is heated?
1. High grease temperatures increase the oxidation rate, doubling it for every 18°F (10°C) rise above 120°F (49°C). High temperature also tends to increase the rate of bleeding and evaporation of the oil. Additionally, grease tends to soften as temperatures increase and may become fluid enough to leak out of housings. Other things being equal, operating at high temperatures will require more frequent relubrication, or the use of a high temperature grease.
What factors influence lubrication frequency?
Operating and other factors that influence re-lubrication frequency include: temperature, continuity of service, quantity of grease in housing, size and speed of bearing, vibration, exposure to contaminants, effectiveness of seals, and the grease’s suitability for the particular service.
Do electric motors need to be relubricated?
Electric motors utilizing double shielded or double sealed bearings, which are typically of the lubricated-for-life design, usually do not require regreasing. On the other hand, all others, those being open or single shielded or sealed bearings, should be re-lubricated periodically to replace grease that has deteriorated, leaked away, or become contaminated. Generally, operating conditions will dictate the relubrication interval required.
Electric motor maintenance
Keep your electric motors in peak condition with some basic maintenance practices that are easy to do.
How to choose grease for electric motor bearings
Grease is frequently used to lubricate electric motor bearings because of its simplicity of application and unique characteristics. Read about what you should consider when choosing the proper grease.
What happens if you don't grease your bearings?
An insufficient amount of grease could lead to bearing failure due to lack of lubrication. On the other hand, over-lubrication can also lead to bearing failure and cause problems due ...
What would happen if the grease was too hot?
High temperatures would accelerate grease deterioration, possibly leading to bearing failure due to lack of lubrication. Furthermore, expansion of the grease could force it into the motor winding, resulting in damage to the motor, or cause seals to rupture.
Can over lubrication cause bearing failure?
On the other hand, over-lubrication can also lead to bearing failure and cause problems due to migration of the lubricant in to the windings. One of the two methods following is frequently used for determining the quantity of grease to be added to a bearing:
Can you grease a bearing housing?
It is common practice to pack the bearings as well as the bearing housing with grease. In addition to holding the bearing in place, the bearing housing also acts as a grease reservoir. The following may be used as a guide to filling the housing with grease.
Which bearing is best for grease supply?
Many bearing users consider the regular single-shielded bearing with the shield facing the grease supply (Figure 2) to be the best arrangement.
What is grease retainer?
A grease retainer labyrinth is designed to prevent grease from reaching the motor windings on the inner side of the bearing.
What is a shielded bearing?
A shielded, grease-lubricated ball bearing (Figure 1) can be compared to a centrifugal pump having the ball-and-cage assembly as its impeller and having the annulus between the stationary shield and the rotating inner race as the eye of the pump. Shielded bearings are not sealed bearings.
What is it called when a bearing is not shielded?
If grease inlet and outlet ports are located on the same side, this bearing is commonly referred to as “conventionally grease-lubricated.”. If grease inlet and outlet ports are located at opposite sides, it is referred to as cross-flow, or cross-lubrication.
Why are high load bearings often supplied without shields?
High-load and/or high-speed bearings are often supplied without shields to allow cooler operating temperature and longer life. One such bearing is illustrated in Figure 4.
What percentage of motor problems originate with bearing problems?
The proprietary in-house statistics of a number of petrochemical plants in the United States indicate that approximately 60 percent of all motor difficulties originate with bearing troubles. If a bearing defect is allowed to progress to the point of failure, far more costly motor rewinding and extensive downtime will often result.
Can bearing life be improved?
Improvements in bearing life should not be difficult to justify, especially if it can be readily established that most incidents of bearing distress are caused by lubrication deficiencies.
Where is the oil port on a motor?
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.
Why does my electric motor overheat?
Watch out: lack of lubrication can cause an electric motor to overheat, go off on thermal overload
What is duty cycle lubrication?
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.
Do electric motors have oil points?
There are no visible oiling points. 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).
