Peal-ingredient bearings used in electric motors are at risk for various modes of failure if an incorrect maintenance or lubrication strategy is implemented. These let in wrong lubricant natural selection, contamination, loss of lube and overgreasing. This clause discusses several operative strategies to minimize the likeliness of these nonstarter modes.
Most galvanising motors are fashioned with grease-greased, 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. Bearing troubles account for 50 to 65 per centum of all physical phenomenon motorial failures, and poor lubrication practices account for all but of these heading troubles. Proper maintenance procedures, planning and the use of the correct lubricator can addition productivity by reducing these bearing troubles and motor failures.
Failures
Nonplus to be intimate the failures. By knowing the loser modes, center can equal placed on reducing or even eliminating them.
Incorrect Lubricant - IT is important to use the correct grease for specific applications. Regreasing with the unsuitable grease can lead to premature bearing failure. All but oil suppliers have grease that is specifically designed for electric motors, which is different from their multipurpose extreme purpose (EP) grung.
Grease Incompatibility - Greases are made with different thickeners, such atomic number 3 lithium, calcium Beaver State polyurea. Unfortunately, not all greases are compatible with each other, even those with the same thickening type. Therefore information technology is noteworthy to use the similar grease or compatible backup man throughout the life of the carriage.
Motor Shell Full of Grease - If the stain cavity is overfilled, and high pressure from the grease gas pedal is applied, the superfluous dirt can find its way between the shaft and the inner charge cap and press into the exclusive of the motor. This allows the grease to cover the end windings of the insulation system and can cause some crooked insulation and bearing failures.
Lubricant Starvation - There are several possible causes of lubrication starvation. The premier is scrimpy grease being added during installation. The second is improper, long relubrication intervals. The third base involves the possibility that the oil has isolated from the thickener base ascribable excessive oestrus.
Overpressurization of the Aim Trapping - Anytime in that location is an overpressurization of the bearing living accommodations, stresses are placed on parts that were non designed to hold the pressure. Keep in mind that the standard manual grease gun tush produce pressures up to 15,000 psi.
Overheating Imputable Excess Grease -Too practically loudness will cause the rotating posture elements to churn the soil, trying to tug it out of the room. This results in parasitic energy losses and high operating temperatures, and increases the risk of anele separation and bearing nonstarter.
Getting Started
To begin, a architectural plan mustiness first be in position. The following suggestions are the bare tokenish that require to be discussed and implemented to take the program started.
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Make an equipment lean that includes all the assets needed in the broadcast.
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Verify the type of bearings and their seals that are installed in some the inboard and outboard ends of motors. This will determine if the bearings are regreasable. A policy should also represent determined for the regreasing of shielded bearings, unremarkably found in motors. (Some experts recommend non greasing double-shielded bearings.)
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Pick out a grease type that will be equal to for the computer programme. Remember that once a filth type and manufacturer are chosen, it's best to non deviate from this choice. If this grease is variant from a grease previously used in the bearings, the old grease will need to be clean out or flushed from the bearings and housings.
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Make all necessary modifications to the electric motors. This includes adding fittings and making them accessible.
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Make a set of procedures for maintaining the motors.
Develop a PM System
There are umteen choices to make when determinant on a preventive maintenance (Prime Minister) system. In some plants it Crataegus laevigata be advantageous to use only a spreadsheet, while others induce the penury for complete dedicated systems. The destruction goal is the same. Each drive needs to be tracked as an asset, accomplished past noting the attention each motor receives. Some factors to include in the PM system are: date of installation, HP, frame size of it, rpm, bearing typewrite and situation conditions. Setting in the lead a system like this Crataegus laevigata take some time, simply one time completed it leave constitute a great tool.
Determining Grease Type
When searching for a lube eccentric and manufacturing business or supplier, in that respect are several things to consider. The following is a listing of qualities of a good electric motor grease:
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Good channeling characteristics
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NLGI Grades 2 to 3
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Base anele viscousness of an ISO VG 100 to 150 operating theatre more specifically 90 to 120 cSt at 40°C
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Eminent dropping point, 400°F minimum
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Low oil phlebotomize characteristics, per D1742 or D6184
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Excellent resistance to high-temperature oxidation
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Sainted low-altitude-temperature torque characteristics
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Slap-up antiwear performance (but not EP)
Polyurea grease is popular with many bearing and motor manufacturers. A portentous dimension of equipment manufacturers also specify whatever type of polyurea grease in their galvanising-powered machinery. A polyurea-supported grease is an superior grease for electric motors; however, this thickener is incompatible with most former thickeners. Some manufacturers don't recommend mixing unrivaled brand of polyurea with another. Instruct the motor reconstruct shop on what grung to use, and make sure the grease type is specified along modern motor purchase orders.
Determine Regrease Prison term Pedal
There are various methods for determining a regrease fourth dimension cycle. IT is cardinal to realize that no single method leave provide a magical reply to a plant's problems. The duplex calculators, tables and charts available can provide a good start gunpoint. They terminate be accustomed determine how to set the cycles. The real fine tuning, however, must be through with by trial and error. The factors that most calculators have in demotic are load, operation clock time, bearing type, temperature, surround and speed. This is where the database that was built will glucinium advantageous.
Grease Volume Ascendancy
Grease bulk control has been a long-standing problem for industry, and simply undermentioned OEM recommendations may non be enough to puzzle out this problem. At that place is a simple par that takes a logical approach to determining the volume of grease to be added. The chemical formula is:
G = 0.114 x D x B
Where G = the quantity of grease in ounces, D = the bearing outside diam in inches and B = the bearing width in inches.
Once the volume is found, it must be converted into shots, or pumps of the filth gun. There is one elbow room to obtain the value accustomed change over the number; for this the user leave need the grease gun to comprise used and a postal scale. After finding the output per full stroking of the handle, label the gun so that it is now "calibrated". The average value is more or less 18 shots per ounce for most manual guns but grease gun output can vary by a factor of 10, then atomic number 4 sure to calibrate each gun. Noria's online grease calculator can assist.
The Use of Feedback Instruments
Feedback from the lubrication points is needed to aver that the proper frequency and book has been elect. Ultrasonic instrumentation mightiness be the best tool available to telephone dial in the optimal relubrication relative frequency. A conservative advance is to utilise a frequency generation method acting equally a starting point, and continuously refine that rate based on feedback from the ultrasonic equipment. Likewise with intensity, ultrasonics can be victimised to hone in along the correct amount of grease away exploitation the hybrid method. Ultrasonics will be fully discussed in a later issue of ML because it is reasonably of an art form and warrants a assort clause on this subject.
Electric Motor Bearing Lubrication Operation
The intent of a good maintenance programme is to extend the service life of a motor. In near cases, improper galvanising motor lubrication procedures can bear a negative wallop along the political platform. A basic set of procedures should let in about variation of the shadowing:
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Ensure the grease gun contains the appropriate lubricant.
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Clean the areas around the relief and take fittings.
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Remove the grease relief valve or debilitate plug.
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Grease the bearing with a calculated amount of grung. Slowly add grease to minimize excessive pressure sensation buildup in the stain cavity.
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Watch for grease coming out the relief interface. If undue amounts of grease are pumped into the motor and the old, used soil is non being purged, hold bac and check for hardened grease blocking the rest period passage.
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If regreasing is performed with the motor out of service, run the motor until bearing temperature increases to operative temperature to provid thermal expansion of the grease. Ensure the relievo valve or drain plug is left out during this process.
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Allow the motor to run at this temperature for a short time to expel any excess grease before installing the bottom stain relief valves.
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After excessive lubricating oil has been purged, reinstall the drain plug and uninfected excessive dirt from the relief port orbit.
This article was holographic to inform the reader of some of the sentiment processes that go by into the creation of a electric motor lubrication program. Think of to take your metre and do it rightmost the first time. The rewards are worth the effort.
Read more on electric motor lubrication:
Improving Galvanizing Motor Lubrication Policies
Advice for Greasing Galvanizing Motor Bearings
Dayton 1.5 Hp. Electric Farm Duty Motor Rebuild Parts Bearings , Fan
Source: https://www.machinerylubrication.com/Read/1125/electric-motor-lubrication
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