According to an indepth study performed by EASA, rebuild motors showed no significant loss of effiency, in fact, in several cases, the efficency rating improved.

Electric motors are vital components for many industries, large or small. Electric motors account for two thirds of all electricity used in industrial or commercial applications. The energy costs of operating an electric motor surpasses the original cost of the electric motor many times over. It is no wonder that the energy efficiency ratings for electric motors are a common concern. We often get presented with this question from customers that are evaluating the cost/benefit of rebuilding a motor versus buying new.

We hope that the following information will help answer this common question.

In a comprehensive study, EASA released their research finding on the efficiency of rebuilt or repaired electric motors. The study evaluated 22 motors of different types, voltages, and horsepower. These motors were placed into 4 groups:

Group A

• 6 low voltage motors (100-150hp, 75=112kW)
• Rewound Once
• Result: Average efficiency change was -0.4% (Range -0.3 to -0.5%)

Group B

• 10 Low voltage motors (60-200hp, 45-150 kW)
• Rewound once
• Result: Average efficiency change was -0.03% (Range +0.2 to -0.2%)

Group C

• 5 low voltage motors (100-200hp, 75-150kW)
• Rewound two or three times
• Result: Average efficiency change was 0.1% (Range +0.7 to -0.6%)

Group D

• 1 Medium voltage motor (300hp, 225kW)
• Formed stator coils rewounce once.
• Result: Average efficiency change was -0.2%

All tests were performed with approved industry practices. These results are clear, repaired electric motors that are properly maintained maintain energy efficiency.

Repair an electric motor, or replace it?
Our customers know that repairing an electric motor can often time be more affordable that buying new, however we realize that there are many other factors to consider.

Contact us today, and the professionals at Priest Electric will work with you to evaluate the option that will best suit your specific needs and requirements.

The three main types of machining processes are turning, drilling and milling and each in turn have many types. Advancement in machining have gone to high levels like Electrical discharge machining (EDM), electro chemical erosion technique, laser cutting, cutting metals with water jets etc. Other machining categories are boring, shaping, planning, broaching and sawing. Turning operations are machining operations that rotate the work piece as the method of moving metal work piece against the cutting tool.

Lathes are principal example of machine tool used in turning. Milling is the operation in which the cutting tool rotates to bring cutting edges to bear against the metal work piece. Milling machines are examples of machine tool used in milling. Drilling is the operation in which holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the metal work piece. Drilling operations are done in so called drill presses but sometimes on lathes or mills.

Other miscellaneous operations are operations that strictly speaking may not be machining operations; they may not be swarf producing operations but these operations are performed at a typical machine tool. Burnishing is an example of a miscellaneous operation. Burnishing does not produce swarf but can be performed at a lathe, mill, or drill press.

In a place like Idaho which is known for food processing, wood industries, machinery, chemical products, paper products, electronic manufacturing, silver mining, science and technology sector, semiconductor manufacturers, PC & peripherals manufacturers like Hewlett Packard, an industrial machine shop in Boise plays a vital role.

With many manufacturing industries in Idaho, professional support for such machine tools through an industrial machine shop becomes very important. Priest Electric plays just that role beyond expectations. The company also specializes in an in- house machine shop that caters to companies requiring all types of machining process under one single roof.

Affinity laws state that a change in pump speed has a cubed effect on the required power. However, when pump speed is changed, the resulting operating point will likely move left or right on the curve, relative to the Best Efficiency Point (BEP). So actual required power may be significantly greater than or somewhat less than the cubed proportion.
Only with the pump curve and system curve data can change in the power required be determined for a change in pump speed.

Our experience in our facility along with industry research involving grease manufacturers, bearing manufacturers, motor manufacturers, our industry’s technical association, and engineering companies input can shed some light on this plight. The major problems are the type of grease, the proper application of the grease, and the frequency of application.

Probably the least understood part of the problem is the grease itself. Grease is approximately ninety percent oil and ten percent thickener. The oil does the lubricating and the thickener keeps the oil in place, picture a sponge holding oil. The problem arises when you mix greases which have different thickeners. The most common thickener or base used in today’s electric motor bearings has a polyurea base. Motors come from the factory with a NLGI-2 Polyurea grease like Chevron SRI-2 or Mobil Polyrex EM. Also whenever you purchase shielded or sealed bearings from bearing manufacturers they almost always come with Polyrex EM in them unless you specify something special. The most common grease used by maintenance departments has a lithium base. Polyurea and Lithium don’t like each other, when mixed, the grease can become pure oil and flow into the motor, leaving no lubrication for the bearing. This explains why we sometimes see motors which are full of oil, the bearings have failed and the user says there is no oil anywhere near that motor. Remember the old cowboy adage “never mix gunpowder and alcohol, cause you can’t shoot it and it tastes terrible” Be sure you know which types of grease your plant uses and know which ones are compatible with one another.

Pillow block bearings, DC motors, couplings, and some crane motor manufacturers may use a different grease (usually a Lithium base), so be careful not to mix them. Also identical motors running in an Arizona copper mine may require different lube than in the artic circle. Also in the food processing industry the most important property of lubricants is that they won’t poison you if they somehow get into the food being processed.

As mentioned above, over greasing is a bigger problem than under greasing. Too much grease can act as insulation and overheat the bearing causing premature failure. It can also can move into the motor and contaminate the windings causing expensive repairs. Attached is a compatibility and frequency guideline to help you in your lubrication needs,

Priest Electric offers a bearing maintenance workshop at your plant or at our shop that goes into much more detail on bearing maintenance, contact your salesman or call our shop. Permanent, absolute bearing protection has a greater effect on motor life than any other decisions made in specifying, equipping, and caring for electric motors_ Keeping bearings lubricated with the right amount of clean, uncontaminated, high quality lubricant allows bearings in most industrial motors to outlast all other components.

Precautions In Motor Greasing

When greasing electric motors, there are a number of precautions that must be considered:
• When electric motors are manufactured, or repaired, grease fittings may be put in place on motors that are not grease able. Your supplier should be able to provide confirmation that the motor may be greased.
• Electric motors must be de-energized and locked/tagged out (LOTO) before greasing.
• There should be no paint on grease fittings.
• The average grease gun will introduce 1 ounce for every 23 strokes. Grease compatibility (See Table 1). The additives in some greases do not mix well and can cause the grease to solidify or liquefy.

Table 1: Grease Compatibility

Greasing Procedure
Following is the standard procedure for greasing ball bearings:

1. 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.
2. Remove the grease relief plug and insert a brush into the grease relief as possible. This will remove any hardened grease. Remove the brush and wipe off any grease.
3. Add grease per Table 2.
4. Allow the motor to operate for approximately 30 to 40 minutes before replacing the grease relief plug. This reduces the chance that bearing housing pressure will develop.

Table 2: Amount of Grease to Use

How Often Should Bearings Be Greased?
Bearings should be lubricated at an average frequency as found in Table 3. Operational environment and type of grease may require more frequent lubrication.

Table 3: Bearing Lubrication Frequency

Conclusion:

It is recommended that the type of grease used on each motor is recorded in order to avoid premature bearing failure. In many cases, you may be able to standardize the type of grease used in the majority of your motors. It is also good practice to let your motor repair center know the type of grease used in a majority of your motors. It is also good practice to let your motor repair center know the type of grease in case the standard grease used by the repair center conflicts with your standard grease.

Grease Compatibility

Grease Compatibility

** Please note that this information is meant to only serve as a guideline for grease compatibility and lubrication frequency. If you have any questions contact Priest Electric at 1-800-234-4089 before changing products or frequency in the field **

The primary mechanical seal consists of a stationary seal and a rotating seal. These seals are extremely flat and “rub” together, lapped within two light bands.   Together these seals prevent leakage because of their flatness and are 85 light bands to one thousandth of an inch. There may be some very minor leakage between these faces however it appears as a vapor.

The secondary seal is the rotating face and is sealed to the shaft by an elastomer, along with the stationary face which is sealed to the stuffing box, gland by a gasket, or another elastomer.  The faces are held together by a combination of spring pressure and hydraulic force created by the fluid that is being sealed. As long as the faces are held together, leakage should not occur.  All shaft movement must take place through the elastomer.  If the shaft cannot move easily through the elastomer, the faces can be pulled open, and leakage can occur.  Once opened, dirt or abrasives can penetrate between the faces. If the rotating components of a mechanical seal rotate against each without some form of lubrication, they would soon wear out due to face friction and generating heat.

The different types of Mechanical Seals:

Rotating seal, stationary seal, unbalanced seal, balanced seal, and the horizontally or vertically mounted seal.  The rotating seal is the most common and is used when the component that holds the springs rotates with the shaft.  In contrast the stationary seal is used when the component that holds the springs is held stationary in the gland plate.

Where the stuffing box pressure creates a wedge shaped force attempting to push the faces apart and the spring pressure tends to push the faces together, an unbalanced seal is used. A balanced seal is used where the seal is engineered with a “step” which allows greater stuffing box pressure to close rather than open the faces, which reduces the face load, reducing the need for spring pressure.

The quality and make of mechanical seals is important. Applying the correct seal for the correct function is extremely important.  Priest Electric is one of the best in the business and will provide the knowledge you need to make sure your pump has the correct mechanical seals.

There are various reasons and factors when deciding to have a motor rewound rather than purchasing a new one.  Rewinding an electric motor is delicate and professional care is needed.  Even a minuscule error throughout the rewinding process could result in a great loss.  Rewinding a motor is not a simple task and it is best to have a professional check out the motor and handle the rewinding process. Priest electric is a company with certified professionals to help you with rewinding your electric motor.

How do you know electric motor rewinding is for you?

When a motor’s insulation is ruined or even just damaged the electricity begins transferring from winding to winding causing excess heat and damages the motor.  Power problems can also result in motor damage.  Routine maintenance including rewinding when necessary will extend the life and productivity of an electric motor.

When the decision to rewind a motor the motor housing is first removed to expose the windings. Photographs and notes may be taken for documentation. The wire from the tabs on the brush pads is very carefully and completely removed. The wind free coils are then cut from the motor. The insulation shown is inspected to make sure if it is in good shape, or if it needs to be repaired or replaced. The armature is then rewound. The exact winding pattern is recreated and number of coils around each winding. The windings are connected and the wires are double checked to make sure the tabs are not touching. When all of this is done the motor housing is then reassembled.

Rewinding an electric motor is a tedious and difficult procedure.  Unless you are experienced, having a professional perform the task will save you money and headache in the long run.  Priest Electric is a reliable service provider trained in electric motor rewinding in Boise, Idaho, Nevada, and Oregon.  They have a full service shop for electric motor repair, and can also provide on-site service.

We though this years show was one of the best ever – and we appreciate all our customers stopping by!

Priest Electric is a featured exhibitor in the 2011 Elko Mining Expo

We invite you to attend what is shaping up to be a record breaking mining expo on June 6th through June 10th, 2011

This mining show is one of the largest and most respected in the U.S., and for the past 20+ years Priest Electric has been a part of this amazing event.

Priest Electric will have several of the newest models featuring the latest technologies in electric motors and pumps.

For over 50 years, Priest Electric has provided premiere electric motor sales, and electric motor repair to mining operations in Nevada, Oregon, and Idaho.

We Will See You At The Expo!  BOOTHS 265-266

• Gland Load
• Internal Pressure
• Shaft Speed
• Media Characteristics
• Minor Equipment Problems

Mechanical Packing Braid Styles

Twisted

Braid Over Braid

Braid Over Core

Mechanical Packing Braid Styles

Hydro-Dynamic

Interbraid

Square Braid

Anti-Keystone Packing

Flowserve is a company still going strong and has managed to keep their title amongst their peers as a world leader in the motor pump industry. Holding strong at 15,000 employees spread out throughout several countries, Flowserve has no plans of minimizing or cutting back their production. The merger between two companies formed what is now known as Flowserve; allowing for a stronger more experienced team.

Flowserve seals and other products are so diversified that this company’s products are used to meet the water flow supply needs of several industries. Listed below you will see a number of Flowserve Products and the history they have served and are still serving in.

• Flowserve pumps have a history reaching back to 1790 when steam pumping engines were used and needed.  Today Flowserve proudly boast of their specialty pumps and systems.
• Flowserve seals have been produced over the last eighty years. Flowserve seals are known throughout the industry as being a trustworthy product that can assist in all sealing needs. The use of Flowserve seals can be found on various rotating application to help provide a safer and more efficient workplace as a result.
• Flowserve valves are unique in that the company allows the customer the ability to customize the valve to whatever his or her water supply needs might be. The goal of Flowserve is to produce top quality valve that are able to endure their tough working environment effectively and efficiently.

Priest Electric offers mechanical seals sales and installation for Flowserve and many other trusted manufacturer brands.  Call 208-459-6351 or Request a bid online

Those who own a vehicle understand what it means to have an alignment problem. During the course of the vehicles lifetime, it most likely will experience road bumps, dips and pot holes that can knock the vehicle out of alignment. When a car is knocked out of alignment, the vehicle owner might begin to notice several things such as the tires of the car begin to vibrate once a certain level of speed is reached. The same can be said for heavy machinery or appliance where the time has been knocked out of line with the center of gravity.

When an object that is designed to rotate within a machine has found itself out of align, then it can cause for the machine to vibrate or rattle. Once this out of place alignment happens, a dynamic balancing will need to take place. Dynamic balancing will help correct the amount of vibration.   It is important that any type of rotating equipment, if unbalanced, undergo dynamic balancing.  When an rotating apparatus is not functioning properly, then it is working harder than normal, and can cause addition problems if left unattended.

By dynamic balancing your rotating equipment, it is able use less energy. The noise and vibration is not only causing a rise in energy cost but the unbalance can also create wear and tear on the machine or equipment pieces. The longer the machine goes without dynamic balancing the closer one gets to shoveling out more and more money to repair other aspects and parts of the machine. What causes rotating equipment to become unbalanced?

A machine can need re-balancing after something creates the machine to go off line or quit its normal rotating cycle. For an example, take a washing machine and over fill it. When clothes are piled into the machine and the machine begins to spin the clothes can tumble around inside and build up along one side creating an imbalance to occur. A loud noise will begin to float out of the laundry room and the clothes are redistributed throughout bring the machine back to its normal rotating cycle.

Priest Electric offers dynamic balancing and all other types of electric motor repair in Boise, all of Idaho, Nevada, and Oregon.  Call 208-459-6351 or Request a bid online.