Why Do Transformers Fail?

Transformers, like most electrical devices, are capable of failure, and given enough time, every transformer is going to fail eventually. Still, if you better understand the potential root causes of those failures, and you work proactively to address them, you can maximize the lifespan of your transformers and avoid downtime.

What causes transformer failure and how do you prevent it?

How Transformers Work

A transformer is a type of electrical appliance that’s designed to change the voltage of electricity. When electricity is transferred over large distances, we rely on power lines, which can handle very high voltages. But these voltages aren’t suitable for most applications, so we need a way to convert the high voltage electricity into lower voltage electricity. Transformers rely on a solid iron core with primary windings and secondary windings to convert the electricity; the ratio of the primary coils to the secondary coils is proportional to the ratio of voltage conversion.

How Transformers Fail

Most people treat their transformers as hidden, passive devices that are tucked away somewhere. But your transformer, when active, is constantly working, feeding electrical power to your facility.

The lifespan of a transformer from a transformer manufacturing company can be expressed with a kind of bathtub-shaped hazard curve. Within this curve are three identifiable phases of development:

  • Infant mortality. Transformers are expected to last 25 years or longer, so if a transformer fails or stops functioning within the first 5 years, it’s considered to be still in its infancy. Most of the causes of failure during this stage are issues with the manufacturer. Buying your transformer from a manufacturer with higher regard for product quality can prevent most of these issues. 
  • Random failure. From 5 years into the lifespan of a transformer to the 25-year mark, failures are exceedingly uncommon. If your transformer is manufactured well enough to avoid infant mortality, it’s probably going to last at least 25 years. Still, random manufacturing errors and aberrant events can cause your transformer to fail.
  • Wear out failure. Like with most complex machines and devices we use on a daily basis, transformers have a finite lifespan. It’s only a matter of time before ordinary wear and tear takes its toll on the device, ultimately rendering it incapable of serving its primary purpose. As you might expect, the older your transformer gets, the more likely this failure is. At the end of the hazard curve, there’s a sharp upward turn, representing a skyrocketing risk of failure.

Infant Mortality Failures

Infant mortality failures are usually attributed to some combination of:

  • Poor materials. If the manufacturing company decides to cut corners and use inferior materials, it’s going to jeopardize the lifespan of the transformer. Think of it like this: would you rather have a dining room table made from thin particle board or solid oak? Oak is much thicker and stronger, making it more resilient to most types of stress. A particle board dining room table might last indefinitely if nothing happens to it, but even small incidents could snap it in half. If weak materials are used in a transformer, which is enduring stress constantly, it’s only a matter of time before it fails prematurely. 
  • Poor craftsmanship. Similarly, poor craftsmanship can create problems with a transformer immediately, rendering it vulnerable to harsh conditions and sometimes setting it up for premature failure. Shoddy welding and insufficient attention to detail can cause flaws that inevitably lead to failure. 
  • Poor quality control. Most construction errors and flaws can be caught with an adequately robust quality control program. But without those quality controls in place, a transformer is much more likely to fail. This is essentially the last chance for the manufacturer to identify potential issues and correct them. 
  • Automation. Highly automated processes save time and money, they can also jeopardize the structural integrity of the finished products. These days, quality control is often automated as well, affording you some level of protection, but automated quality control has weaknesses as well.
  • Transportation and installation issues. Sometimes, a transformer is manufactured perfectly well, but it suffers damage during transportation or installation. This is why it’s so important to do your due diligence and work with shippers and installers who know what they’re doing. 

Random Failures

Random failures could be the result of:

  • Manufacturing problems. Sometimes, manufacturing issues don’t become apparent until years after using a transformer. These are like time-delayed versions of infant mortality mechanical failures. 
  • Unfavorable operating conditions. Transient over-voltages, power surges, and overloading are just a few examples of unfavorable operating conditions. If these poor operating conditions are repeated or sustained, the chances of a “random” midlife failure increase. 
  • Random destructive events. When a bolt of lightning strikes a transformer, the result can be a massive explosion. Other types of direct damage can cause your transformer to fail as well. 

Wear Out Failures

Wear out failures become increasingly likely with time, so the older your transformer gets, the more likely you are to see the end result of years’ worth of:

  • Heat. High temperature, with enough time, can cause any transformer to fail. 
  • Vibrations. Vibrations can shake components loose and damage internal components irreparably.
  • Electromagnetic stresses. Transformers deal with high voltages and face severe electromagnetic stresses that do damage over time.
  • Mechanical stresses. And, of course, mechanical stress can also play a role in failure.

Collectively, these sources of minor damage and stress accumulate, increasing the chances of some internal component failing or becoming damaged beyond repair. 

How to Prevent Transformers From Failing Prematurely

So, what can you do to prevent Transformers from failing prematurely? Wear and tear is to be expected, so there isn’t much you can do to prolong the lifespan of a transformer without radically changing the conditions in which you use it. Similarly, while there are some safeguards that can help you reduce a transformer’s exposure to potential hazards, there isn’t much you can do about random events like lightning strikes.

The most important thing you can do is buy transformers from a reliable, quality manufacturer. When these devices are planned and constructed responsibly, with quality assurance checks in place, the rates of infant mortality and random failures plummet.


To Top

Pin It on Pinterest

Share This