When you’re looking for a transformer, the first thing you need to determine is whether to get a dry type or liquid-cooled transformer. There are pros and cons for each, and while oil-filled transformers are sometimes the better option, most people will get more out of a dry type transformer.
Unlike dry types, oil-filled transformers are excellent for high-voltage applications when the transformer can be installed outside, away from buildings and people. However, a dry type can meet most people’s needs. If you have a choice between the two types, here’s why a dry type transformer will outperform one filled with oil.
1. A dry type transformer can last for decades
While liquid transformers are highly prone to explosions and fire caused by various mechanical failures, a dry type transformer made to high standards should last for decades without failing. While there are dry types on the market that don’t last long, it’s because of the lack of craftsmanship.
The difference lies in the insulation materials and the time, attention, and care that go into winding the transformers. When they’re wound by a machine, they’re likely to result in errors that can include poor airflow and loose windings. Hand-wound transformers made by expert craftsmen that are inspected and tested are far less likely to fail.
When it comes to a conductor, copper is superior to aluminum because it resists short circuits better and is more durable in the long run. The ultimate insulation is DuPont Nomex, which can withstand heat up to 200 degrees Celsius. When you’re looking at dry type transformers, you can’t get any better insulation than that.
2. Dry types are safer than oil-cooled
Fire safety should always be a priority. Therefore, when you have a choice between an oil-cooled and dry type transformer, the safer option is the dry type. While it’s cheaper to use mineral oil to cool a transformer, that oil is highly flammable and often leads to explosions and fires. If you’ve ever seen a news story about a transformer exploding, or you’ve heard one blow in person, it’s almost always an oil transformer. Sometimes, they’re struck by lightning, and other times, it’s just an internal failure that causes the oil to ignite.
If you need to install a transformer inside of a building, you never want to use one filled with oil. This creates a major safety risk and fire hazard that won’t be present with a dry type. Although you can use high flashpoint, less flammable fluid, what about containment for any leaks?
Dry type transformers are cooled by forced air and do not contain any liquid. They pose a minimal safety risk and can be safely installed indoors, which brings up the next point…
3. Dry type transformers are predominantly installed indoors
In addition to being safer, dry type transformers are built to run cool and quiet, which means they can be installed indoors in places where people gather without creating a disruption. For example, they are commonly installed in schools, universities, hospitals, office buildings, and more. With a NEMA type 3 enclosure, they can also be installed outside, as long as the heat and humidity are only moderate.
4. A quality dry type will cost less over time
It’s never a good idea to save money by buying cheap items. There will almost always be undesirable consequences. Oil-cooled transformers seem more affordable at first glance, but they experience failure at a much higher rate than dry types. You’ll also need to perform maintenance and repairs far more often on a liquid transformer.
The ideal solution to save money over time is to go with a dry type. However, you can’t just choose any manufacturer. You need a high-quality dry type made by experts.
There are three reasons transformers end up failing:
- Poor craftsmanship
- Poor-quality insulation materials
- Inferior design
When you buy a transformer from a reputable manufacturer in the industry that puts a sharp focus on quality, you won’t need to worry about any of these things. You’ll get a high-quality unit that will last longer and will cost you less money in repairs and maintenance over time.
Choose dry type transformers when possible
Dry type transformers offer a variety of benefits you can’t get from an oil-filled transformer. If you’re looking for a new or refurbished unit, and you have a choice between the two types, choose a dry type. It will cost you a little bit more upfront, but when you buy from a reputable leader in the industry, you’ll get a transformer that is built to last, you’ll have fewer maintenance needs, and it won’t be a major fire hazard.
