Unplanned Transformer Failure Warning Signs

“My transformer is just a couple of years old – It’s going to last for years.”

You may not think you need a new transformer today, but how do you know? Transformers are an afterthought for most because they don’t experience failures that often – but when they do, it could really cost you if you’re not prepared.

The biggest impact for an unplanned failure is the cost for your facility to not have power. How long can your facility be without power? For some manufacturers, every hour could cost you tens of thousands of dollars in lost business if they’re not up and running. Other facilities may have emergency measures in place, such as generators, but many of those cost thousands per hour just in fuel costs. Not to mention the cost of a rush job to get a new transformer installed.

That’s why we’ve prepared this checklist for you to check on the status of your transformer. If your transformer meets any of the below criteria, it could be time to consider a replacement.


ELSCO’s Unplanned Failure Warning Signs Checklist


1. Old age
Age is the biggest contributor to unplanned failures. Over time, dirt collection and heavy usage breaks your unit’s insulation down. If your transformer is over 20 years old, it’s worth considering its condition so that you’re not surprised by an unplanned failure.


2. Already had an outage, or have a damaged transformer
If you’ve already had an outage, this indicates that your transformer could have an issue, or was possibly damaged due to immediate power surge when the power coming back on. Additionally, some incidents could occur without your knowing, and could have weakened your transformer in the process.


3. Unusual amount of noise or vibration coming from the transformer
If your transformer sounds like it’s making more noise that usual, or has gradually gotten louder over time, it’s time to consider the health of your transformer. Similarly, if your transformer is gradually vibrating more, it could be headed toward a failure in the near future.

4. Dirty working conditions
Dirty can reduce the life, safety and performance of your transformer. Overtime, that buildup can degrade the insulation and cause your transformer to run hotter than it needs to. This can shorten its life. If your working conditions are unusually dirty or your transformer isn’t in a secure housing, you may want to consider your replacement options soon.


5. Poorly installed
A poor install could make your transformer noisy, reduce its performance and longevity. If your transformer has any of the following issues, you may want to take a closer look at the state of your transformer:

A. bus bars are not directly connected to your facilities power unit (compare to flexible cable connection between bus bars)
B. if the electrical hookups were not properly cleaned after varnishing
C. your transformer’s base is sitting directly on concrete or steel, with no rubber feet

6. Adding capacity or upgrading equipment
Transformers are built to handle a certain amount of power. If your unit is currently at capacity and you wish to add more power to it, you could push the unit beyond its potential and cause an unplanned failure.


7. Preventative maintenance
Regular check-ups help to ensure that your unit is free of anything inhibiting its longevity, safety and performance. Have you performed any recent tests on the unit to detect any abnormal behavior?


8. Back up plan
What if your unit were to go down today, unexpectedly? How long could your facility go without power? How much would it cost you each day your power was off? Unplanned failures could really cost you – how much money would you lose every hour if your power went down? Generators are an emergency option, but they are very expensive. Simple preventative measures can ensure that you don’t end up with a surprise failure.

9. Power Factor test near a score of 1%
It might be hard to check your purchase order, but there’s a chance it’s on record somewhere. The power factor test measures the dryness of the transformer’s insulation. Although 1% is the legal limit for transformers, most transformers are at or near that level, indicating a lower quality transformer – meaning it has a shorter life and less-efficient performance. ELSCO dry-type transformers are consistently at or below .1 because of their high-quality manufacturing. The lower your score, the greater the safety, longevity and performance.


10. Poor quality transformer
According to industry veteran failure analyst, Jeff Jones, low quality is the #1 cause for premature failure. Not all transformers are the same, despite their similar appearance. Some new transformers have failed in less than two years because of their poor quality. The craftsmanship, materials and design will indicate the manufactured quality – here’s what to look for. If anything is out of place, it could indicate a lower quality unit:

A. Craftsmanship:

i. Are the cooling sticks on your transformer cores lined up neatly, or are they out of alignment causing the structure to potentially warp slightly?
ii. Is the core wrapped neatly or are the edges out of alignment?
iii. Are the transformer core leads welded or bolted to the upper bus bars? A weld indicates a more efficient connection.

B. Materials:

i. Though harder to determine, DuPont’s Nomex insulation is the best in the industry due to its durability.

C. Design:

i. Circular transformer cores are better quality compared to a rectangular design
ii. Copper, circular windings are of better quality compared to aluminum circular windings; though insulated rectangular wire is the most durable.

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