It’s important to understand that there are two main types of low-voltage transformers: Electronic and Magnetic. When we say “low-voltage” we are referring to 12 volt and 24 volt.
Low Voltage Lamps & Transformers
One of the most important things to remember with low-voltage lamps is to make sure they are operating at their full light output. All low-voltage halogen lamps are designed to operate at 12 or 24 volts. Although low-voltage lamps can be dimmed, if they are run at a lower light level all the time, the chemical reaction in the halogen bulb won’t work properly, and the lamps can blacken. If this happens, the lamp should be turned up high and run at its maximum voltage for at least 15 minutes.
The biggest positive benefit of electronic transformers is they tend to be very small and less expensive. But electronic transformers are sensitive to heat, so if you put them in a metal fixture or in a fixture with a canopy and the fixture gets hotter than its recommended temperature, the transformer’s lifespan will be cut short. In fact, for every five degrees Celsius it gets over its recommended temperature, the transformer’s lifespan is cut in half. Since they only have about a five- to six-year lifespan when operating properly, this means their realistic lifespan is even shorter. Also, electronic transformers are known for being noisy, and tenants will often complain of a buzzing or humming sound coming from their transformers.
When it comes to magnetic transformers, there are two types: stack laminated transformers, which are square, and toroidal transformers, which are shaped like a wire doughnut.
Like electronic transformers, the stack laminated transformers are inexpensive but they have the added benefit of a longer lifespan, usually about 15 to 20 years. However, the stack laminated transformers only operate at about 80 to 85 percent efficiency, and are known for being noisy.
Toroidal transformers are more energy efficient. They operate at about 90 to 95 percent efficiency and can run for a very long time, anywhere from 20 to 25 years. They also are much quieter so you can place them closer to the fixtures, rather than having to run wires a long way from the transformer to the fixture itself. The downside to toroidal transformers is their cost but when you consider energy savings, you can actually gain that back in a short period of time.