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Annual Electric Motor Checklist for Reliability

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The New Year’s Resolution Guide to Your Motors

As we step into the new year, it’s the perfect time to reflect on the health and readiness of your operations. Electric motors and their ancillary parts are critical to keeping your business running smoothly, yet they’re often taken for granted until something goes wrong. This year, let’s resolve to take a proactive approach to maintaining these essential assets. Here are some key areas to review and optimize:

1. Do You Have the Right Spares on Hand?

Unexpected motor failures can lead to costly downtime. Having a spare motor ready can make all the difference in maintaining continuity. But how do you know when you need a spare? Our guide provides actionable insights to help you decide when investing in a spare is the right move for your operations.

In addition to keeping spare motors on hands, you may want to evaluate keeping spare parts on hand. These parts may include bearings, pulleys, or specialized parts like encoders. We keep a large stock of spare parts on hand for the hundreds of repairs that we conduct every month. Furthermore, we keep a stock of spare parts for different industries such as the Machine Tool and Printing industries. Make sure that you store these parts properly. Below we show a picture of rotors for servo motors that are wrapped to prevent dust and other contaminates from impacting the material.

Spare Parts for Motors

2. Are You Storing Your Spare Motors Properly?

Having a spare motor is one thing, but improper storage can render it unusable when you need it most. Factors like temperature, humidity, and physical protection play a critical role in extending the life of stored motors. Learn how to store electric motors properly to ensure they’re ready for action. We keep a large inventory of spare motors at our headquarters for the Machine Tool and Printing industries. These motors are wrapped and stored in a humidity, climate controlled environment.

spare motors in storage

 

3. Is Your Preventative Maintenance Schedule Up to Date?

Preventative maintenance is the cornerstone of reliable motor performance. Regular inspections and servicing can identify issues before they become costly problems. This blog outlines the benefits of a consistent maintenance schedule and how it can save you time and money.

For facilities with DC motors, there are specific maintenance needs to consider, such as brush inspections and replacements. Check out our detailed guide to ensure your DC motors are in peak condition.

4. Are You Installing and Maintaining Belts Correctly?

Belt-driven systems are common in many operations, but improper tension or installation can lead to inefficiency, wear, and failure. Learn how improper belt tension affects your belt drive system and discover common belt problems that you can address proactively.

5. Have You Scheduled Infrared Analysis?

Infrared inspections are a highly effective way to identify potential issues with your equipment before they escalate. Many property insurance companies favor facilities that conduct regular infrared analysis, so it’s worth discussing this with your insurance provider. Explore the benefits of infrared inspection and consider scheduling this service as part of your annual maintenance plan.

Infrared Inspection

Infrared Inspection

6. Are You Leveraging Vibration Analysis?

Vibration analysis can be a powerful tool in predicting motor maintenance needs or determining when a motor requires repair or replacement. Regular vibration checks can detect imbalances, misalignments, or bearing issues before they lead to significant downtime. We work with our customers to create tailored schedules—whether quarterly, monthly, or bi-annually—to suit their operational demands. Learn more about vibration analysis and how it can benefit your facility.

Start the Year Right

By addressing these key areas, you can set the foundation for a smoother, more efficient operation in the year ahead. Let’s make the new year where we prioritize reliability and efficiency for electric motors and their supporting systems. If you have any questions or need assistance with your motor maintenance strategy, don’t hesitate to reach out. Here’s to a successful and proactive year ahead!

Electric Motor Core Loss Testing

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Core loss testing is a vital yet often overlooked step in electric motor maintenance and repair. By accurately measuring power loss within the motor’s core, this test helps identify underlying issues that can compromise efficiency, increase operating temperatures, and shorten the motor’s lifespan. In this blog, we’ll explore the importance of core loss testing, the methods involved, and how it can help ensure your motors are running at peak performance, saving you time and money in the long run.

What is a motor core?

The core of an electric motor plays a fundamental role in its operation, serving as the foundation for the stator windings and providing the magnetic circuit necessary for converting electrical energy into mechanical motion.  The core is made of stacked laminations of electrical steel, must maintain its structural integrity to support the magnetic flux generated during motor operation. Any damage or distortion to the core, whether from improper stripping methods like burnout ovens or other factors, can compromise the motor’s performance. Core integrity directly impacts the motor’s efficiency, as any disruptions in the magnetic circuit can lead to increased core losses, reduced power output, and decreased overall efficiency. Therefore, preserving core integrity through Motor Safe Stripping is essential for ensuring the optimal functioning of electric motors in various industrial and commercial applications.

MotorSafe lamintions vs Burnout Oven laminations

On the left, you see a lamination stack in a motor’s core after Dreisilker performed its MotorSafe Repair Method to strip the windings. On the right, you can see a lamination stack after burning out the windings. The Motor Safe Stripping Method (left) maintains the core’s integrity.

What is core loss testing?

Core loss testing is a diagnostic procedure used to evaluate the efficiency and performance of the stator core in electric motors by measuring the losses incurred during operation. These losses primarily consist of hysteresis losses, which occur due to the magnetic material’s resistance to changes in magnetization, and eddy current losses, which are induced currents that flow within the core material itself, generating heat and wasting energy. During core loss testing, technicians apply a specific voltage to the motor and measure the resulting current, allowing them to calculate the core losses under various operating conditions. This testing is essential for identifying potential issues such as overheating, insulation degradation, or structural damage within the core, which can adversely affect the motor’s efficiency and reliability. By conducting core loss testing, technicians can ensure that the motor operates at optimal performance levels, thereby extending its lifespan and reducing energy consumption.

Core loss testing a motor

Our experienced Winder core loss testing a motor during the repair process.

 

How core loss testing can impact reliability:

Distortion of the core and the presence of hot spots in an electric motor can significantly impact its efficiency and overall performance. Core distortion, often caused by uneven heating or excessive temperatures during processes like burnout oven stripping, can lead to misalignment of laminations and structural irregularities within the core material. This distortion disrupts the magnetic circuit essential for motor operation, resulting in increased core losses and reduced magnetic efficiency. Hot spots, localized areas of overheating within the core, can further exacerbate efficiency issues by causing thermal stress, insulation breakdown, and potential damage to the core material. These hot spots create inefficiencies in the motor’s operation, leading to energy losses, decreased power output, and compromised reliability.

Electric motor core loss testing

Infrared image of an electric motor’s core. It shows hot spots which would lead to inefficiencies during operation.

At Dreisilker, we utilizing our MotorSafe Stripping method to safely remove motor windings during a repair. Through proper temperature control, insulation removal techniques, and post-stripping inspections is crucial to maintaining optimal motor efficiency and performance. During the repair, if we find that the motor’s core has hot spots, we consult our customers on whether it is recommended to replace the core.

Overall, core loss testing is a critical diagnostic tool in electric motor repair. By testing and addressing core losses, we can ensure the reliability, efficiency, and longevity of electric motors, ultimately leading to cost savings and improved performance. Learn more about our full rewinding services to see all of the steps within a rewind.

Environmental Impact of the Burnout Oven Electric Motor Repair Process

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It is increasingly important to understand how our decisions impact the environment and energy consumption in every day life. These decisions are also important for when you are selecting your electric motor repair partner. Understanding the different methods of electric motor repair and how they impact your electric motor’s efficiency and reliability are crucial. In this article, we will walk you through how the burnout oven electric motor repair process impacts your motors and review how Dreisilker’s MotorSafe Repair method differs.

What is the burnout oven electric motor repair process?

The burnout stripping method is a long-established technique utilized in the repair of electric motors to remove insulation and varnish from stator windings in preparation for rewinding. This process involves placing the stator in a specialized oven set to a high temperature, typically around 650°F, for an extended period, often exceeding eight hours. The intense heat effectively turns the insulation and varnish materials on the windings into ash, facilitating their complete removal. While this method is highly effective in preparing the stator for the application of new windings, it carries potential risks and challenges. These include possible damage to the stator core and frame from excessive heat, environmental concerns due to the release of gasses and byproducts, significant energy consumption, and the generation of waste materials that require proper disposal.

100HP After Burnout Oven

A 100HP Motor after the Burnout Process

How core integrity impacts electric motor efficiency:

The core of an electric motor plays a fundamental role in its operation, serving as the foundation for the stator windings and providing the magnetic circuit necessary for converting electrical energy into mechanical motion. Core integrity is paramount in ensuring the motor’s reliability, efficiency, and longevity. The core, typically made of stacked laminations of electrical steel, must maintain its structural integrity to support the magnetic flux generated during motor operation. Any damage or distortion to the core, whether from improper stripping methods or other factors, can compromise the motor’s performance. Issues with the core can lead to increased core losses, reduced power output, limited lifespan, and decreased overall efficiency.

To maintain optimal motor performance, core loss testing is a critical aspect of electric motor repair and maintenance. This process involves assessing the core losses in the stator core to evaluate the motor’s efficiency and performance. By measuring core losses, which include hysteresis and eddy current losses within the core material, technicians can identify any abnormalities or damage that may have occurred during the repair process, such as stripping and rewinding. Core loss testing ensures that the motor operates within optimal efficiency levels and can detect issues like core overheating, insulation breakdown, or structural damage. Conducting thorough core loss testing as part of the repair procedure allows technicians to verify the integrity of the stator core and make informed decisions regarding any necessary corrective actions to maintain the motor’s efficiency and longevity.

Considerations for use of the burnout oven motor repair process:

One of the critical factors affecting core integrity during the burnout oven process is temperature control. Excessive temperatures can lead to thermal stress and damage to the stator core and frame. It is essential to adhere to recommended temperature settings (around 650°F) and duration to prevent overheating and potential core damage. If you are working with a repair shop that utilizes the burnout method, it is important to inquire about their quality procedures for temperature control. Through our many years of experience, we have found that many repair shops may ignore the 650°F guideline and increase the temperature to expedite the process. While this might speed up the turnaround time, it can also negatively impact the motor’s efficiency.

Another significant consideration is the potential for core distortion and hot spots within the motor. Core distortion, often caused by uneven heating or excessive temperatures during the burnout process, can lead to misalignment of laminations and structural irregularities within the core material. This disruption of the magnetic circuit essential for motor operation results in increased core losses and reduced magnetic efficiency. Additionally, hot spots—localized areas of overheating—can further exacerbate efficiency issues by causing thermal stress, insulation breakdown, and potential damage to the core material. These inefficiencies lead to energy losses, decreased power output, and compromised reliability. Therefore, careful management of the burnout stripping process is crucial to minimize these risks and ensure optimal motor performance.

Alternatives to the burnout oven:

Recognizing the challenges and environmental concerns associated with the burnout oven method, we at Dreisilker have developed an alternative solution known as the MotorSafe Repair process. In a comprehensive study, we compared the burnout oven method with our MotorSafe approach, highlighting the significant advantages of our method in terms of both performance and environmental impact. Read more on the study here: MotorSafe vs Burnout Method Comparison

The MotorSafe Repair process prioritizes the protection of core integrity, minimizes energy consumption, and reduces the release of harmful emissions. In the following sections, we will delve into the specifics of the MotorSafe Repair process, discuss our study’s findings, and explore the environmental benefits that make MotorSafe a superior choice for electric motor repair. Additionally, we will refer to an article that further explains how the MotorSafe method positively impacts the environment, underscoring our commitment to sustainability and efficiency in motor repair.

MotorSafe lamintions vs Burnout Oven laminations

Laminations after the MotorSafe Repair Method (left) vs the Burnout Oven Method (right)

Environmental Impact of the MotorSafe Electric Motor Repair Process

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The MotorSafe Electric Motor Repair process plays a important role in promoting environmental sustainability and aiding companies in achieving their green goals. By focusing on efficiency and precision, our repair method focuses on a motor’s efficiency, optimizes motor lifespans, and enhances resource efficiency. As a result, MotorSafe Repair ensures the efficiencies of motors to optimize their energy consumption for critical operations. The MotorSafe Repair process can have a positive impact on the environment and help companies meet their sustainability goals in several ways:

Focus on Energy Consumption: The biggest impact an electric motor repair service center can have on a motor’s energy consumption is within the rewinding process. If a motor is found to need a rewind, it is important to understand how the windings are stripped. With our MotorSafe Repair Method, we measure a motor’s core loss before and after stripping. The core loss testing process checks for overheating, damage, and hot spots within the motor’s core. A motor that does not pass our core loss testing would not run efficiently, leading to possible overheating and a shortened life span. In this case, we would recommend replacement of the core (when possible) to avoid efficiency issues. After the core loss testing, we proceed with our MotorSafe Stripping Method which safely removes the coils from the motor – ensuring no further degradation to the motor’s core. In contrast to MotorSafe Stripping, the industry standard Burnout Incineration method (used by other electric motor repair facilities) can introduce electric motors to considerable, damaging heat. At Dreisilker, we always conduct the core loss test before and after the stripping process to confirm the motor’s core condition.

To learn more about the environmental impact of electric motor repair, read our study: Burnout Oven vs MotorSafe Repair

Core loss testing a motor

Testing a motor’s core.

Materials Used in the Repair: A critical part of a motor’s efficiency includes the materials used in the repair. There are many standards imposed by the National Electrical Manufacturers Association (NEMA) that impacts how motors are manufactured and how we repair our motors. The standards created by NEMA can dictated the type of copper wire, the insulation paper, the varnish, and etc. Our skilled rewinding technicians examine the motor we received, its nameplate, and its data packs to understand what replacement material we need to use throughout the repair.

We use Class H wire in our rewinding method and we carry Class N rated varnish, which allows the windings to withstand higher temperatures. Furthermore, the varnish is hermetic rated which impacts the operations of compressor motors.

Taking Extra Steps: There are many ways how taking extra steps during a repair can impact the efficiency and longevity of motors. For example:

  • Crease and Cuffing: We use high quality slot paper that we crease and cuff for every slot. The cuff allows for mechanical rigidity of the windings, limiting vibration and increasing reliability. Read more here: The Basic Steps of an Electric Motor Rewind
  • Tying down slots: We tie down every slot during a rewind which helps aid the cuffs for mechanical rigidity. Most repair facilities and ever manufacturers take a short cut and tie down every other slot to save time. Read more here: The Basic Steps of an Electric Motor Rewind
  •  Proper cool down: During the double dip and bake varnish process, we let the windings cool after curing in the oven before dipping them again in varnish. Allowing the motor to cool ensures the varnish adheres properly to the windings. If the motor is too hot, the varnish will become too viscous and run off the windings more easily. Read more here: 4 Types of Motor Winding Insulation Methods

Dreisilker Winding Components

Dreisilker’s rewind for a random wound motor.

Recycling: Dreisilker works with certified partners in order to recycle and dispose of materials from the electric motor repair process. Throughout a typical motor repair, it is possible for us to need to replace many components of the motor including bearings, coils, end bells, shafts and more. Our technicians are trained on how to sort and recycle these different types of materials. Sorting different resources enables us to collaborate with our partners to properly recycle materials, ensuring they can be reused. Like many other industries, we use solvents and chemicals within the repair process. We partner with chemical disposal companies so that we are limiting the environmental impact of these used chemicals.

In conclusion, the MotorSafe Electric Motor Repair process acknowledges the need for environmental sustainability and supports companies in meeting their green goals. By emphasizing energy efficiency, precision in repair techniques, and the use of high-quality materials, MotorSafe enhances motor performance and longevity. Our meticulous approach to rewinding, repairing, and material selection ensures motors operate optimally, reducing energy consumption and minimizing environmental impact. Additionally, our commitment to responsible recycling and disposal practices underscores our dedication to sustainability. By adopting the MotorSafe Repair method, companies can achieve greater operational efficiency while aligning with their environmental and sustainability objectives.

Field Winding Failures for Printing Press Main Drive DC Motors

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The reliability of main drive DC motors is paramount for printing presses. Yet, one persistent challenge that operators often grapple with is the occurrence of field winding failures. These failures not only disrupt production schedules but also pose significant maintenance headaches. Understanding the causes and implications surrounding field winding failures is crucial for maintaining uninterrupted workflow and ensuring the longevity of printing press machinery.

Overheated Field Windings in Main Drive DC Motors

Overheated field windings represent a prevalent issue encountered in printing press motors, often stemming from the continuous operation of these windings. In many printing press control systems, field windings are designed to remain energized consistently to ensure swift motor response and readiness for immediate use. However, this perpetual activation can lead to excessive heat buildup within the windings, eventually causing them to overheat. The resultant thermal stress gradually deteriorates the insulation and conductivity of the windings, compromising their efficiency and lifespan. Moreover, prolonged overheating can trigger thermal runaway, exacerbating the problem and potentially culminating in catastrophic motor failure. Effectively managing the temperature of field windings through strategic control schemes and periodic monitoring is indispensable for mitigating this common cause of printing press motor malfunctions.

Field Coil Shorted to Ground in Main Drive DC Motors

Another prevalent issue afflicting printing press motors is field coil shorted to ground, which can significantly disrupt motor performance and reliability. This problem often arises due to insulation breakdown or physical damage to the field coil windings, leading to an unintended electrical connection between the coil and the motor’s grounded frame. When a field coil becomes shorted to ground, it creates an electrical pathway that diverts current away from its intended circuit, resulting in erratic motor behavior, decreased efficiency, and potential safety hazards. Moreover, the continuous flow of current through the shorted coil can exacerbate overheating, exacerbating the risk of further damage and escalating maintenance costs. Detecting and rectifying field coil shorts promptly through comprehensive insulation testing and meticulous visual inspections are essential steps in preserving the integrity and longevity of printing press motors.

 

Stator Windings

Field Coil Shorted to Ground.

Dreisilker’s Proactive Solutions for Printing Press Motors

At Dreisilker, we understand the importance of minimizing downtime for our customers, especially when it comes to critical equipment like printing press motors. To address this need, we offer a proactive solution by pre-winding stator, field, and interpole coils for certain models with commonly encountered motor configurations. By pre-winding these essential components, we significantly reduce emergency turnaround times, enabling our customers to swiftly replace faulty coils and restore motor functionality with minimal disruption to their operations. This proactive approach not only enhances operational efficiency but also demonstrates our commitment to delivering timely and effective solutions tailored to the specific needs of our customers. With Dreisilker’s pre-winding services, our customers can confidently navigate motor maintenance challenges and maintain seamless productivity in their printing press operations. Call us today to start your program.

Printing Press Repair Services

Our expertise goes further than just rewinds for printing press main drive motors. Check out our full capabilities here: Printing Press Motor Repair

Crucial Wear Parts for Vacuum Pumps

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In industrial machinery, timely access to wear parts is crucial for vacuum pumps. This rings especially true for side channel and radial vein vacuum blowers. Join us as we explore the challenges of obtaining these parts and discover practical solutions for smoother procurement processes.

Side Channel Vacuum Blower Common Part Failures

When it comes to side channel blowers, two common parts often face lengthy lead times for replacements: casted aluminum blower wheels and filters. The casted aluminum blower wheels, essential for generating airflow within the blower, are prone to wear and tear over time. However, their intricate design and material requirements contribute to extended procurement periods. Similarly, filters play a crucial role in maintaining air quality and preventing debris from entering the system. Yet, sourcing replacements for these filters can prove challenging due to their specific dimensions and filtration capabilities. Addressing these common part failures requires proactive planning and alternative sourcing strategies to minimize downtime and ensure continued operation of side channel blowers.

Casted Aluminum Blower Wheel

Testing a Vacuum Pump

Radial Vein Vacuum Pump Common Part Failures

Radial vein vacuum pumps have several critical components that often encounter prolonged lead times for replacements, causing disruptions in operations. Among these, carbon veins stand out as a common culprit. These veins, integral for creating vacuum pressure within the pump, undergo significant stress during operation, leading to wear and degradation over time. Consequently, sourcing suitable replacements with precise specifications and material requirements can pose a considerable challenge, contributing to extended lead times. Additionally, specialized seals play a vital role in maintaining the pump’s efficiency and preventing leakage. However, their unique design and material composition often lead to delays in procurement. Furthermore, pump end plates, essential for enclosing and supporting internal components, are susceptible to wear and damage, necessitating timely replacements. Given the critical nature of these components, proactive measures such as inventory management and alternative sourcing strategies are essential to mitigate the impact of long lead times and ensure uninterrupted operation of radial vein vacuum pumps.

Vacuum Pump Parts Stocking Program  

Dreisilker offers a comprehensive Stocking Program designed to streamline the procurement process for common or critical vacuum pump components. With their expertise, they can assist in auditing or reviewing your inventory to ensure that essential parts are readily available when needed. By stocking these parts, Dreisilker significantly reduces lead times, potentially shortening them by months and minimizing downtime for your operations. Moreover, in emergency situations, Dreisilker excels in providing swift turnaround times, ensuring that your vacuum pump systems are back up and running with minimal delay. With Dreisilker’s stocking program, you can rely on their proactive approach to inventory management and responsive service to keep your operations running smoothly and efficiently.

Vacuum Pump Motor Brands We Service:

Understanding NEMA and IEC Standards for Electric Motors

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Electric motors are the workhorses of countless industries and households, powering everything from industrial machinery to household appliances. To ensure reliability, safety, and interoperability, standards have been established by organizations like the National Electrical Manufacturers Association (NEMA) and the International Electrotechnical Commission (IEC). Let’s delve into these standards and understand their significance in the realm of electric motors.

NEMA Standards

What is NEMA?

NEMA is a trade association representing the interests of electrical equipment manufacturers in the United States. It sets standards for various electrical products, including electric motors. Find the NEMA standards for electric motors here.

Importance of NEMA Standards:

NEMA standards provide guidelines for motor design, performance, and testing, ensuring consistency and quality across the industry. These standards cover aspects such as motor dimensions, mounting configurations, enclosure types, and performance characteristics.

Impact on Electric Motors:

  1. Enclosure Types: NEMA specifies various enclosure types (such as open drip-proof, totally enclosed fan-cooled, etc.), which dictate the motor’s protection against environmental factors like dust, moisture, and corrosive substances.
  2. Mounting Configurations: NEMA standards define mounting arrangements for motors, facilitating compatibility with different types of machinery and equipment.
  3. Performance Ratings: NEMA provides performance classifications based on horsepower, speed, and efficiency, aiding consumers in selecting the right motor for their applications.
  4. Efficiency Considerations: NEMA standards also address energy efficiency, with classifications like NEMA Premium Efficiency, which indicates motors that meet or exceed stringent efficiency requirements, helping users reduce energy consumption and operational costs.

IEC Standards

What is IEC?

The International Electrotechnical Commission is a global organization that develops and publishes international standards for electrical technologies.

Importance of IEC Standards:

IEC standards promote uniformity and compatibility in electrical systems worldwide. They provide a common framework for manufacturers, regulators, and consumers, facilitating trade and technological advancement.

Impact on Electric Motors:

  1. Global Compatibility: IEC standards are recognized internationally, ensuring that motors manufactured according to these standards can be used across different regions without compatibility issues.
  2. Technical Specifications: IEC standards cover motor design, performance, and testing procedures, similar to NEMA standards, but with some variations in terminology and methodology.
  3. Efficiency Regulations: IEC has its efficiency classification system, such as IE (International Efficiency) ratings, which categorize motors based on their energy efficiency levels.

Harmonization with NEMA:

While NEMA and IEC standards have some differences, efforts are made to harmonize them where possible to minimize trade barriers and promote global interoperability in the electric motor industry.

Importance for Industry and Efficiencies

  1. Quality Assurance: Both NEMA and IEC standards provide benchmarks for motor quality, reliability, and performance, giving consumers confidence in the products they purchase.
  2. Interoperability: Standardization facilitates interchangeability of motors and components, streamlining manufacturing processes and reducing lead times for equipment installation and maintenance.
  3. Energy Efficiency: With the focus on efficiency ratings, standards drive the development and adoption of energy-efficient motor technologies, contributing to sustainability efforts and cost savings for users.
  4. Regulatory Compliance: Adhering to NEMA and IEC standards ensures compliance with regulatory requirements, avoiding potential legal and safety issues associated with non-compliant products.

In conclusion, NEMA and IEC standards play pivotal roles in shaping the electric motor industry, guiding design, manufacturing, and usage practices. By adhering to these standards, manufacturers and consumers alike benefit from enhanced reliability, performance, and energy efficiency in electric motor applications, paving the way for a more sustainable and technologically advanced future.

Not sure how NEMA or IEC Standards impact your operations? Contact your local Dreisilker representative and learn more.

 

Getting Ready for Manufacturing Success: When to have a Spare Electric Motor

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When it comes to running a manufacturing operation, it is important to understand when you should have a spare electric motor available in case of repairs or breakdowns. Electric motor failure can be very costly in terms of downtime for your factory. Having a spare motor can also prevent a costly downtime, which can have a significant impact on your production timeline.

There are a few different questions that you should ask to determine if you should have a spare electric motor:

How critical is the electric motor to your operations?

If you operate an industrial setting where speed is of the essence, an extra electric motor ready to go can be essential. Manufacturing and industrial work can often be hampered by machine breakdowns, and an electric motor that needs to be sent off for repairs can cause a considerable disruption in the flow of production. This problem can be alleviated with the addition of a spare electric motor, allowing you to resume normalcy and keep errors to a minimum.

How unique is the electric motor?

Often times, special equipment comes with special electric motors. These motors are not easily replaced and often time require repair. Check with your vendor of the machine or our motor experts to determine how unique your electric motor is. Working with the manufacturer or motor experts can help you determine the availability of replacement parts and whether or not you should have a spare on hand.

spare motors in storage

At Dreisilker, we have built an inventory of spare motors for the Machine Tool (CNC) and Printing industries so that we can be there for our customers. While some of these spare motors are unique, we also have many unique motors on hand. Call your Dreisilker motor expert to learn more about our inventory of these special motors and how we can help you with your business continuity strategy.

How old is the electric motor and its machine?

Similar to the uniqueness of your electric motor, your electric motor could be obsoleted by the equipment manufacturer. These means that the motor may not be available anymore for replacement or that the lead  time for a new motor can take months. A spare motor can bridge the gap in this situation, ensuring the machinery doesn’t have to sit idle while waiting on a new part.

1939 1000HP Westinghouse Motor

Here’s a 1000 HP Westinghouse motor that was originally manufactured in 1939. We were happy to help our customer repair this motor back to its former glory. We don’t often see motors as old as this come through our doors! We did look for a replacement motor for our customer, but because of the age of the motor, it was not an option.

What is the cost of a spare electric motor?

If you determine that your electric motor is critical to your operations, it does not hurt to receive a quote for a spare electric motor from your motor experts. Our skilled customer service representatives are happy to help quote a motor for you so that you can make an educated decision on when to have a spare electric motor on the shelf. We have helped customers work with their operations manager to evaluate the cost of downtime with the cost of a spare motor or a repaired motor.

Considerations for your spare electric motor:

If you do make the decision to keep a spare electric motor on your shelf, make sure that you follow our guide on how to keep this spare motor in top condition.

For these reasons and more, having a spare electric motor on-hand can be a cost-savings measure in the long run. At Dreisilker Electric Motors, we have a wide range of electric motor repair, sales, and field services to ensure your manufacturing operations maintain peak efficiency and performance. Contact us today to find the perfect solution for your business.”

The Basic Steps of an Electric Motor Rewind

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the basic steps of an electric motor rewind

Talk to an expert about Motor Rewinding

 

 

1. Documentation and Testing before an Electric Motor Rewind

  • We conduct a coreloss test before stripping
  • Measure and record physical dimensions
  • Cut the winding head for preservation of data

2. Electric Motor Rewind: Stripping

The stripping of your windings is a very important part of the repair process. Ask your shop how they strip your windings. Dreisilker utilizes MotorSafe stripping that protect the motor and its laminations.

3. Additional Testing

We conduct another core loss test after stripping to make sure the stripping process didn’t damage anything. Plus we compare the results to the previous core loss testing results to see whether or not hot spots were removed.

4.Wire Selection for an Electric Motor Rewind

Our stripping method leaves us with a winding head and 3 phase coils. This allows us to choose the appropriate wire for your motor. We always use Class H insulated wire or better.

5. Automated Coil Winding

We utilize computerized coil winding machines which ensures every phase of your motor has the same length of coils, creating equal resistance and inductance within each phase.

6. Crease and Cuffing during an Electric Motor Rewind

We use high quality slot paper that we crease and cuff for every slot. This allows for mechanical rigidity of the windings which limits vibration and increases reliability.

7. Electric Motor Coil Insertion

Our experienced winders take great care not to damage the copper wire’s enamel while inserting the slow. We use a temporary sleeve to protect the wire from scratches when inserting the coils into the slots.

8. Tie Down Slots during an Electric Motor Rewind

Our winders take the time to tie down every slot. This helps to ensure rigidity of the winding head, reducing vibration and improving reliability. Some repair shops and even motor manufacturers take a short cut and tie down every other slot.

9. Final Testing of an Electric Motor Rewind

To ensure quality of our windings, we conduct many tests including visual inspection, hi pot, milliohm resistance, insulation resistance, surge testing, rotation test, record current, and more.

Considerations for Water Cooled Injection Molding Machine Motor Repair

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The plastic industry relies on injection molding machines to produce part after part. To endure the high demand, the motors on injection molding machines are manufactured to withstand extreme environments. The motors are water cooled and are unique compared to a standard motor. When repairing these motors, you should consider how your repair shop strips the motor of its coils, how it is rewound and how the windings are varnished.

Disassembled Water Cooled Injection Molding Machine Motor

Disassembled Water Cooled Motor

The stripping methods used by standard motor shops can be detrimental to water cooled motors. These shops use the Burnout Oven method where the motors are placed in an incineration oven to heat up the varnish to make the coils pliable. Burnout oven temperatures exceed 680°F which compromise the integrity of the core with frame damage & distortion. While distortion of any motor housing is unacceptable, a unique problem with water cooled motors is the warping of the motor housing causing a leak in the water jacket. A faulty water jacket can allow the coolant to leak and contaminate other components of the motor.

Similar to the issues with a distorted water jacket, water cooled motors may have rubber o-rings that are susceptible to the high heat of the Burnout Oven. When introduced to high temperatures, the o-rings can melt causing leakage of the coolant. This leakage can contaminate the windings, bearings, electronic components and etc. This contamination can result in a slew of problems including but not limited to damaged bearings, imbalance of rotating equipment, and breakdown of insulation. To learn more about the effects of contamination and how to prevent it, read our article Electric Motor and Generator Failures from Contamination.

Unlike other motor repair shops, Dreisilker uses its MotorSafe Stripping method in place of the Burnout Incineration Method. In our MotorSafe Stripping method, we gently warm the outside diameter of the laminations to 400 degrees F with induction or non-contact natural gas. Once heated, we hydraulically remove coils preserving 3 phase groups for data. Our method of motor stripping protects the motor housing and specialized elements of a motor such as a water jacket or o-rings.

After stripping of a motor, rewinding the motor is a critical step of the repair process. We make sure to wind the motors back to OEM specifications or better using computer-controlled technology. The original wire size and wiring data are recorded so that we can replicate the motor’s winding with uniformity and accuracy. Other shops may change specifications, substitute with inferior materials, or modify the original design.

When a motor is rewound, the windings need to be varnished to protect the motor windings from contamination and ensure electric conductivity. The typical repair shop method for varnishing a motor is the dip and bake method. While we use this method for common motor applications, we trickle varnish water-cooled motors to match the OEM standards (for water-cooled motors).

Trickle varnishing is accomplished by connecting the windings to a rotating table and using electrical resistance to heat the windings during rotation. Once at temperature, a tiny stream of varnish is trickled onto the winding head. The varnish follows the wire into the entirety of the slot, eliminating chances for partial discharge in random windings. Once fully saturated, the current is increased in the windings, resulting in the varnish curing while on the machine. This process is faster and better than the traditional dip and bake process because it cures on the machine – making it ideal for emergency repairs. Check out more varnishing techniques in our article 4 Types of Motor Winding Insulation Methods.

How your water cooled injection molding machine motors are repaired is very important to the reliability and lifetime of your motor. If you need your water cooled motor repaired, make sure you consider which method is used for stripping the motor, how the motor is rewound and how the windings are varnished. If you have any questions on how our repair method for water cooled motors is different, feel free to call us today.