Magnetic Transformers

Magnetic transformers are isolated transformers of the "core and coil" type. The reason it is described as a "core and coil" transformer is because inside the transformer there is a metal core (that is why magnetic transformers are so heavy) and wrapped around this metal core is a "coil" or copper wire. Voltage is reduced through magnetic fields, thus the name magnetic transformer. To further define all of the available magnetic transformers for the Ambiance® Lighting Systems there are three subdivisions: laminated integral, laminated remote and toroidal.

For optimal operation, we recommend that the load on any Ambiance® Lighting Systems laminated magnetic transformer should be between 50 and 100% of the maximum load. For example, the transformers are designed to have an output of 12 volts when loaded 100%. When the load is only 50% of the maximum, the output is approximately 12.6V. As the load decreases, the voltage increases. As the voltage increases above 12.6 volts, the lamps are being over-driven. When this happens, the lamp's light output increases, thus potentially ending lamp life prematurely. So, over-driving the lamps will significantly shorten their lamp life.

Ambiance® RX Lighting Systems' magnetic toroidal transformers are designed to operate with loads between 0% and 100% of the rated capacity of the transformer. The "50%" rule does not apply to toroidal transformers.

Integral Laminated Magnetic Transformers

Integral magnetic transformers are usually found in low voltage recessed housings, or in some other manufacturer's track fixtures. In a recessed fixture, the integral magnetic transformer is located on the side of the wiring compartment (junction box). Since the components of a recessed fixture are hidden above the ceiling, the size, weight and appearance of a transformer is not a consideration. Usually, there is one transformer per fixture, the transformer powers 50 watt lamps maximum, and the transformer is cased in a 2" x 2" x 2" metal box (for electrical and safety reasons). In track fixtures, the integral magnetic transformers are located inside of the track fixture and below the track itself.

To differentiate between line voltage and low voltage track fixtures with magnetic integral transformers, you can look at three things: (1) the physical characteristics (some transformers are encased in a box or the fixture housing, allowing the fixture to be moved anywhere along the 120 volt track or the fixture socket accepts a bi-pin lamp), (2) the weight of the low voltage fixture is substantially greater, and (3) the lamp specifications for use with the fixture.

Remote Laminated Magnetic Transformers

Remote laminated magnetic transformers are larger in size and weight and, as the name states, are designed to mount in a remote location. A remote location could be above a ceiling (with access), in the attic (be aware of high ambient temperatures!), in a suitable cabinet (e.g., kitchen base cabinet) or basement/crawl space.

Remote transformer outputs vary from a minimum of 150 watts to a maximum of 300 watts per output, at 12 volts; and range from 250 watts to a maximum 500 watts per output at 24 volts. Each transformer can have from one up to two outputs, each individually protected with a short circuit protection on the low voltage side.

Remote transformers are available either at the designated voltage or in multi-tap versions. The various taps are 12-13-14-15 volts for a multi tap, "12 volt" transformer and 24-26-28-30 volts for a multi tap "24 volt" transformer. Further explanation is contained later in this module.

Surface Mounted Toroidal Transformers

The third type of magnetic transformer mounts below the ceiling cavity and is visible on the ceiling or wall surface. These are found in the Ambiance® RX Lighting System and are encased in a decorative housing to match the finish of the system components. The surface mounted transformers are toroidal transformers that will be further defined in a later paragraph. Toroidal transformers are perfect for surface mounting due to their lower profile construction.

12 volts vs. 24 volts

A 24 volt system should be considered in installations where there are long runs of incandescent lights, such as in cove ceilings, or in certain other commercial applications. There is up to 70 % less voltage drop using a 24 volt system than when using a comparable 12 volt system. Voltage drop is characterized by a difference in lamp brightness at the lamp closest to the transformer (or beginning of a run) versus the lamp farthest from the transformer (end of the run). One way voltage drop can be minimized is by placing the transformer in the center of the run and have multiple runs come out of it. This would reduce the length of the run, and reduce the load of the run. Another way to ensure that voltage drop is minimal is contained in the calculation chart located on the Voltage Drop Technical page. Please refer for a further definition and methods to minimize voltage drop.

(Hint: Do not mix different voltages within the same job. If 24 volts is determined best suited for a room, the other rooms should follow the same voltage specification. This allows an easy identification when lamps need to be replaced.)

What Are the Attributes of a Quality Magnetic Transformer?

Before we define a quality transformer, we must present this caution. Never, yes NEVER, use a "buck-boost" transformer to power lighting systems. A buck-boost transformer is a cheap, no frills transformer that was not intended to be used in low voltage lighting applications. A "buck-boost" transformer was designed to power industrial machinery and does not have the necessary safeguards to prevent problems as do good quality magnetic transformers specifically designed for low voltage lighting systems.

• Sea Gull Lighting laminated magnetic transformers have been manufactured with a Faraday shield. The Faraday shield stops the primary line (120V) from coming in contact with the secondary windings (12V), and thus preventing a short. Also, the shield prevents harmful electrical noise from being transmitted through the electrical system and eliminates any harm to sensitive computer or other electronic equipment.
• All Sea Gull Lighting magnetic transformers are encased and potted with epoxy (asphalt type of material) to reduce vibration and humming.
• All Sea Gull Lighting laminated magnetic transformers have a built-in thermostat in the primary side of the transformer. In the event of excessive heat in the transformer, this thermostat acts to disconnect itself from the primary side (120V), before any damage can occur. This feature provides protection from any excessive heat and subsequent fire to surroundings.
• All Sea Gull Lighting transformers are supplied with circuit breakers for the secondary side (12V) or the load side. This will shut the transformer down in case of a short circuit on the load or conductors (cable) which would cause excessive heat and damage the system. All circuit breakers are designed so that the operating ambient temperature is considered to prevent nuisance tripping. The ambient temperature refers to the temperature of air, surrounding the circuit breaker. Nuisance trips refer to circuit breaker trips that could be caused by a non-damaging inrush or start-up current surges, as opposed to an over current that may cause dangerous overheating such as by a short circuit. This applies to practical situations such as display cases and also to attics in the South and Southwest.
• Some Sea Gull Lighting laminated magnetic transformers have a boost tap. A boost tap is a feature that increases the secondary output by 5%, which may compensate for voltage drop. Voltage drop is an effect of increased wattage (load) and length (run), where the voltage and the lamp brightness near the transformer are higher than the end of the run. The multi-tap versions of Ambiance® Lighting Systems' remote transformers do not contain a boost tap. For long runs or higher wattages which produce severe voltage drop, the multi tap transformers allow the flexibility of using a higher voltage to reduce or eliminate severe voltage drop which could compromise the design and the system. We will cover voltage drop and methods for reduction in Module 4.

Following these guideline will insure that the transformers used within the Ambiance® Lighting Systems will be trouble free and will comply with the specifications, U.L. or E.T.L. listings and warranties associated with each system.

Toroidal Transformers

For the Ambiance® RX Lighting System, we use a special type of transformer, called a toroidal transformer, where it is determined that the transformer must be surface mounted.

Most toroids are smaller than their laminated magnetic transformer counterparts. Electrical and lighting designers appreciate a toroid's compact dimensions. They are particularly well suited where low height is a consideration such as surface mounting.

Due to the special insulators and a tightly wound core, toroids can be extremely quiet in their operation. Toroids can be up to 50% lighter, (depending on power rating), than conventional laminated transformers because they are more efficient. A toroid's potentially low weight simplifies end product design by reducing mounting hardware and supporting enclosure requirements.

The Ambiance® RX system's toroidal transformers have the following quality and safety characteristics:

• Circuit Breakers
• Dimming core
• Insulators to minimize vibration and noise

Surface mounting is as easy as installing a standard lighting fixture.

The following summarizes important information about toroidal transformers:

• Toroidal transformers are core and coil, isolated type magnetic transformers.
• Each transformer features a resettable magnetic circuit breaker on secondary side (12V) to protect against shorts.
• Ambiance® RX Lighting System toroidal transformers feature an integral dimming coil to reduce any audible noise when installed using a dimming control device.
• Toroidal transformers' housings are designed to be visible and are particularly well suited where low height is a consideration such as surface mounting.
• Ambiance® RX Lighting System toroidal transformers are available in 12 volts only.
• Toroidal transformers may be loaded between 0% and 100% and will still operate efficiently