Electric Motors • Perfomance Systems
Are your electric motor bearings wearing out long before they should? The problem might be bearing fluting … and the good news is that there are ways to prevent it.
Fluting is a form of electrical damage suffered by electric motor bearings when alternating (AC) or direct (DC) current actually passes through the metal bearing. As the currents pass through the bearings, they can leave behind surface damage that results in premature bearing failure.
The winding insulation on your electric motor has a major impact on its life expectancy and reliability, which means that using the wrong insulation class could be very costly. The best way to avoid this mistake is to be familiar with the basics of NEMA insulation classes.
You've got a electric motor that needs to be repaired yesterday, but you're also working with a pretty constrained budget. You've got a electric motor repair vendor in mind, but you've heard that they outsource work. Is that a smart choice?
The capabilities of electric motor repair shops can vary significantly. One shop might be able to manufacture an expertly engineered motor from a shell of a stator while another is just a two man crew that does bearing swaps. When you use a shop that doesn't have extensive capabilities, you run the risk that they will outsource critical aspects of your motor's repair to someone else.
Due to limitations -- which could involve tools, equipment, money, or technicians -- a shop may find it best to outsource some of the electric motor repairs they are responsible for. Some repair shops are able to do all repairs in house, while others may use a hybrid approach where only certain repair jobs are outsourced. However, there are some motor repair shops that outsource almost everything.
There are quite a few reasons behind repair shops choosing to outsource. In some instances, it may be more economical for them (but not necessarily for you!) to send certain repair jobs out to other shops. For example, good technicians can be hard to come by, especially if a repair shop isn't willing to pay for talent and experience.
The equipment and tools needed to support repairs may be more expensive that the shop can afford. This is often true with tasks such as motor rewinding as well as VPI. And it may be an issue of having the space for the right equipment to perform certain repairs. This can especially be true when it comes to repair large motors and A-NEMA motors.
How many times can you repair an electric motor? It's a question that comes up from time to time and the answer is actually pretty straight forward, but it might be worth going through the processes to understand it more clearly.
Is there a limit to how many times you can have a motor repaired before you can't do it anymore? The short answer is that an electric motor can be repaired indefinitely. There is a caveat, however: there is a limit to how many times you can simply recondition a motor as repeated varnish dips eventually will require a burnout and rewind. Let's take a look at the process to better understand the limitations.
What you may think is just a "mom & pop", local electric motor repair shop may have more capabilities and a farther reach than you think.
People often assume that a local shop is only going to have a local reach with little capabilities. For example, let's say your facility is in Chicago and you need a repair shop to keep your motors and drive-trains running. But, you've heard some good things about a shop in Kalamazoo and have found the information on their site helpful. But you figure the Kalamazoo shop doesn't have the reach to meet your motor repair needs, so you settle for a local shop. After all, it is more convenient and they seem to do fine with repairing your motors ... or do they?
The truth is that distance does matter, but not always in the way you think. When looking at motor repair and maintenance, it is easy to assume that a shorter distance means a better option. Keep in mind that there is the possibility that sending your motors to a shop further away could mean access to better quality repairs.
A little math often shows that the extra costs associated with distance might pay for themselves if the repair quality with more expertise, experience & equipment. Some research and a few phone calls might reveal that the Kalamazoo motor repair shop charges are still extremely competitive with your local shop. Also, you might be surprised to learn that the Kalamazoo shop partners with certified local shops in other states, including yours.
There is so much more to the electric motor repair industry than just repairing motors. Some repair professionals go above and beyond the status quo by associating with EASA and seeking accreditation to affirm their commitment to reliability, efficiency, and performance.
You may have run across the acronym EASA when looking for electric motor dealers or repair services. EASA stands for Electrical Apparatus Service Association. EASA is a formal association that motor repair shops can utilize to remain actively involved in their industry.
EASA is an international trade organization and a recognized leader in sales, repair, and service of electro-mechanical systems (which includes electric motors, generators, pumps, and powertrains). According to EASA, they "[provide] an ongoing flow of industry information and education that helps members worldwide serve as total solution providers for electrical and mechanical equipment and system."
Every motor repair shop is basically the same so it doesn't matter where you take your motor, right? Wrong! If you want to find out why this is so wrong, keep reading.
In my years in the electric motor repair industry, I have learned that if you have seen a motor shop, you have seen ONE motor shop. Each individual shop is truly unique, with its own specialty or individual approach to repairs. The same is true for the repair that you're taking in because each motor has its own quirks and issues.
From one electric motor repair shop to another, there can be major differences in method of repair, tolerances allowed, pass versus fail readings, etc. Each shop is going to have its own approach and methods to repairing a motor. And that means that the data taken and the repairs performed are only as good as the individual shop and the actual individual that performs them!
This is a (9) nine minute segment of a larger (1) one hour presentation given by Mark Hatfield, Chief Executive Officer of HECO - All Systems Go at the 2017 Reliability Process & Maintenance Symposium.
This covers a variety of aspects of selecting and managing electric motor repairs. From developing an electric motor repair specification, qualifying and validating repair vendors, developing condition and assessment reports, final report standards, and finally implementing fixed pricing for motor repairs through a pricing matrix.
It’s interesting how rarely this question is ever discussed. Can the electric motor shop that you use, run your motor or properly power it with full voltage? Or do they simply spin the motor up to full speed/volts, “for a moment”, but then have to reduce the voltage because their power supply can’t handle the load?
The below video is a 15 minute segment of an hour long presentation given by Todd Hatfield of HECO at the 2017 Reliability, Process, and Maintenance (RPM) Symposium. This presentation discusses common preventable causes of electric motor failures. This section of the presentation discusses bearing related failures as bearings account for about 51% of all electric motor failures.
