|Electronic Transformer - Frequently Asked Questions
If you have any further questions after reading our FAQs, please contact us at:
1. CAN LIGHTECH'S ELECTRONIC LOW VOLTAGE TRANSFORMERS BE DIMMED USING A WALL DIMMER OR A CENTRAL DIMMING SYSTEM?
Yes, all of the electronic low voltage transformers are dimmable.
2. WHAT TYPE OF WALL DIMMER CAN I USE?
The transformers can be dimmed with any “trailing edge” or “reverse phase” wall dimmers which are commonly called electronic low voltage dimmers. These will average $65-$75 in cost and can be purchased in most lighting stores/showrooms or from an electrical distributor. These will be harder to find in hardware or home improvement stores.
3. ARE THERE LESS EXPENSIVE WALL DIMMERS AVAILABLE?
Yes. These “leading edge” or “forward phase” controls are commonly called incandescent dimmers. These can be purchased for less than $30 in most hardware or home improvement stores. Lightech transformers can be controlled with many, not all, of these types of dimmers. For dimming Lightech’s DC transformer versions or the 300-watt transformers you should use an electronic low voltage dimmer for the best result. If you want to use these lower cost incandescent dimmers, we suggest contacting the dimmer manufacturer prior to purchase for any recommendations on models to use with an electronic low voltage transformer. Some dimming manufacturers recommend using only electronic low voltage dimmers to dim any electronic low voltage transformer. Any of Lightech’s transformers can be dimmed with any electronic low voltage wall dimmer (‘trailing edge”).
4. CAN ELECTRONIC TRANSFORMERS BE DIMMED IF I INSTALL A CENTRAL DIMMING SYSTEM?
Yes. Central dimming systems vary in their features and complexity so it is always best to contact the dimmer manufacturer before purchase or installation to let them know you will be using electronic low voltage transformers. The dimming manufacturer can suggest the appropriate dimming modules, wall dimmers, interfaces, etc. for their dimming system. Lightech transformers can be dimmed using any trailing edge or reverse phase control.
5. WHAT TYPES OF LAMPS (LIGHT BULBS) CAN BE USED WITH YOUR TRANSFORMERS AND IS THERE A MINIMUM AMOUNT OF WATTAGE THAT I NEED TO CONNECT TO THE TRANSFORMER?
The transformers are designed to power low voltage (12V or 24V) halogen or xenon lamps. Lightech’s specifications sheets on this website will show the minimum load (wattage) you must have connected to the transformer for proper operation as well as the maximum wattage you can have connected to the transformer. Lightech’s new LET 60 AC 120 12 CL2 Low-Watt version is a 60-watt transformer for 120V input power that only requires a minimum connected load of 2.9 watts. Some companies are designing very low wattage LED products so they can be powered by electronic transformers. You should not use transformers to power LEDs if the manufacturer does not specifically state that their LED product can be powered with electronic transformers that have a high frequency AC output (between 30-40kHz). Lightech also makes a complete line of power supplies for LEDs. These are often called LED Converters or LED Drivers.
6. WHAT SHOULD I KNOW BEFORE WIRING THE FIXTURE TO THE TRANSFORMER?
Loose connections anywhere on the low voltage side of the transformer will cause transformers to operate at an elevated temperature that may exceed the maximum case temperature of the transformer. This can affect the proper operation and shorten the life of a transformer. When joining two or more wires together you should twist (snake) the wires around each other before placing a wire nut or other type of wire connector over this connection. This “snaking” of wires maximizes the surface contact area of the wires you are joining together for better wire-to-wire contact. If the fixture comes with “terminal block” types of connectors make sure the wires are fully inserted into the terminal block and then tighten the screws to securely grip the wires in inside the terminal block. If your light fixture is a track, monorail or cable lighting system make sure the fixture heads are securely fastened to the rail, track or cables. Check all of the fixture heads whenever you are replacing lamps to make sure they remain securely fastened. Check the lamps (light bulbs) to make sure they are fully inserted into lampholders (sockets) and that the two pins of the low voltage lamps are being firmly gripped by the lampholders. Any lampholders (sockets) that are not securely gripping the lamps and have excessive play should be replaced. Install all of the lamps in the fixture before turning the power on to the fixture.
7. I INSTALLED A NEW LOW VOLTAGE LIGHTING FIXTURE AND IT DOES NOT WORK. WHAT COULD BE WRONG?
This can sometimes occur if the fixture was turned on before installing all of the lamps in the fixture. Try switching off power to the fixture for five seconds and then switching the fixture back on. The transformers have a short-circuit protection feature that will not allow the transformer to supply power to the fixture until the electrical short is removed. Turn off power to the fixture and look for any possible shorts. Inspect the wires coming into and out of the transformer to make sure there are no nicks in the wire insulation as a result of wires being pinched inside part of the fixture. Closely inspect the fixture for possible shorts. Check your wiring connections again. Switch the power to the fixture back on to see if this solves the problem. There is another simple test method for the transformer described in question #12.
8. WHY WOULD MY LIGHT FIXTURE BE CYCLING ON AND OFF?
This is common when the transformer reaches an extremely high temperature. This is not a normal condition. The transformer has a thermal cut-off protection feature that shuts down the output of the transformer when it reaches an extremely high temperature. When the transformer has cooled to a normal operating temperature the protective feature will allow the transformer to power the fixture again. The cycling is an indication the transformer is repeatedly reaching an extremely high temperature and this requires an inspection of the wiring connections and the fixture as outlined in question #6. Do not continue operating the fixture in this condition for an extended period of time. Fixture manufacturers usually perform a heat test of the transformer when it is inside their fixture. This heat test may determine the maximum wattage rating of the fixture and the maximum wattage per lampholder (socket) to ensure the transformer does not exceed its maximum case temperature when it is enclosed inside their fixture. This is why the maximum wattage rating of the fixture might be lower than the maximum wattage of the transformer. Add the wattages of all the lamps in your fixture and make sure this total wattage does not exceed the fixture manufacturer’s maximum wattage rating. If you have installed a Lightech transformer into a fixture that came from the manufacturer with a different transformer inside, the Lightech transformer could be exceeding its maximum case temperature when enclosed in the fixture. Reducing the connected wattage (load) will reduce the operating temperature of the transformer. Another common cause for the transformer to operate at a very high temperature are loose connections anywhere on the low voltage side of the transformer. See Question #6.
9. MY LIGHT FIXTURE SOMETIMES DIMS BY ITSELF AND THEN RETURNS TO A NORMAL LIGHT LEVEL. WHY WOULD MY FIXTURE BE DOING THIS?
If the transformer reaches a high temperature the transformer will dim the light fixture by reducing the output voltage of the transformer. This dimming is proportional to the rise in temperature above the maximum case temperature rating of the transformer. This is an auto-thermal regulation feature on many of Lightech’s transformer versions (not all) that is a patented protection feature. Add the wattages of all the lamps in your fixture and make sure this total wattage does not exceed the fixture manufacturer’s maximum wattage rating. Other possible causes for the transformer to be dimming the light fixture are covered in Question #6.
10. WHY WOULD I MEASURE NO OUTPUT VOLTAGE ON MY METER FROM A NEW TRANSFORMER?
First, you must make sure that a lamp load (the fixture with light bulbs) is connected to the output side of the transformer. Connect the lamp load before turning on the power to the transformer. Some transformers will not produce any output voltage unless the lamp load is connected prior to applying power (switching on) to the transformer. It may also be the type of meter that you are using and this is covered in question #11.
11. MY VOLTMETER GIVES AN ACCURATE MEASUREMENT OF THE INPUT VOLTAGE COMING INTO THE TRANSFORMER BUT MY VOLTMETER MEASURES NO OUTPUT VOLTAGE OR AN ABNORMALLY LOW OUTPUT VOLTAGE FROM THE TRANSFORMER.
First, you must make sure that a lamp load (the fixture with light bulbs) is connected to the output side of the transformer before turning on the power to the transformer. Some transformers will not produce any output voltage unless the lamp load is connected prior to applying power (switching on) to the transformer. If power to the transformer is switched on first and then lamps are inserted into the fixture sockets you may not get any output voltage until you turn the transformer off for 3-5 seconds and then switch it back on again. This is a protection feature in the transformer. You will not read any output voltage from the transformer if there is a short anywhere on the low voltage side of the transformer or in the fixture. The short-circuit protection of the transformer will shut down the output voltage of the transformer until the short is removed. A simple way to isolate the transformer for testing is covered in question #12. Electronic transformers have a high frequency output that cannot be accurately measured unless the meter is a True RMS meter that is capable of reading the high frequency output of electronic transformers. You may have an expensive meter but it may not have this measurement capability. Lightech’s AC transformers have an AC output that is between 30-40kHz. A True RMS meter that can read up to 40kHz is required to get an accurate voltage reading on the output side of the transformer.
12. I AM AN ELECTRICIAN BUT I DON’T HAVE A METER TO PROPERLY MEASURE THE OUTPUT VOLTAGE OF ELECTRONIC TRANSFORMERS. HOW CAN I TEST THE OUTPUT OF THE TRANSFORMER WITHOUT ONE OF THESE METERS?
North American transformers with a 120V input voltage are used in residential applications and some commercial buildings. Transformers with a 277V input voltage are used in commercial buildings. The input wire colors (high voltage side) are (1) black wire and (1) white wire. The output wires (low voltage side) of the transformer connect to the lighting fixture. The two wires having the same color (two blue wires for 12V versions or two purple wires for the 24V versions) are the output wires.
13. WHAT IS A TRANSFORMER?
A transformer is a device that changes the voltage. It is made by winding two wires around an iron core, one connected to the primary side and a second wire connected to the secondary side. In the case of low-voltage halogen lighting, the transformer has an input or primary voltage of 120, 230, 240 or 277V and an output or secondary voltage of 12V or 24V.
14. WHAT IS AN ELECTRONIC TRANSFORMER?
Conventional transformers, also called electromagnetic transformers are extremely large and heavy, and consist of an iron core and the sets of wire. An electronic transformer, on the other hand, also contains an electronic device, an inverter, which allows the size of the actual transformer to be reduced. This electronic device and the reduced size output transformer make up the main components of what we normally call an electronic transformer.
15. HOW DOES AN ELECTRONIC TRANSFORMER WORK?
The inverter conditions the current to change direction at a frequency of about 20-50,000 times per second (called 20-50,000 Hertz or Hz) as opposed to the power from your wall outlet, which changes direction at a frequency of 50 or 60Hz. The higher the frequency of the current, the smaller the transformer. Most electronic transformers on the market today provide (high frequency) AC output.
16. WHAT IS A DC TRANSFORMER?
A DC transformer is a conventional electronic transformer where the output is converted to DC with the help of a device called a rectifier. The DC output virtually eliminates drop voltage and reduces radiated RFI. A DC transformer, although smaller and lighter than a magnetic transformer, is usually slightly larger than an AC electronic transformer providing similar power.
17. WHAT IS THE ADVANTAGE OF AN ELECTRONIC TRANSFORMER?
Electronic transformers are very small and light compared to magnetic transformers, in most cases small enough that fixture manufacturers can often incorporate them within a lighting product rather than leaving the customer to find a hiding place. Even when not incorporated with the fixture, electronic transformers are easy to handle and install.
18. HOW DOES ONE WIRE A TRANSFORMER?
The transformer should be connected to the wires leading to the lighting fixture using wire nuts or terminal blocks of appropriate size (for solid contact). Please check carefully that input wires are connected to the power line and output wires to the lamp. Low-voltage halogen systems carry relatively large currents so all connections must be very tight to prevent a fire hazard. If transformer is equipped with wires, then you will usually find the thicker wires on the low voltage side and not vice versa.
19. HOW DOES THE USE OF AN ELECTRONIC TRANSFORMER DIFFER FROM THE USE OF A MAGNETIC TRANSFORMER?
The output of an electronic transformer, unless it is a DC transformer, is high frequency. This has the consequence that there is substantial voltage drop if the wires carrying the current are long or far apart. Always obey the following rules to avoid a voltage drop. Use thick wires on the secondary/output side. The thicker the wire the less drop voltage you will experience. The shorter the distance between transformer and lamp the less drop voltage you will experience. Try to use a pair of secondary wires that are twisted together. When a transformer powers more than one fixture, split the output of the transformer immediately into several separate circuits rather than carrying all the power in one pair of wires. The less power per circuit, the less drop voltage you will experience. I.e. A 300W lamp/circuit will have more severe drop voltage than a 50W lamp/circuit.
20. IS THE TRANSFORMER HARD WIRED TO THE POWER BOX OR DOES IT HAVE A PLUG ON THE END OF IT?
All our transformers except for model 12V/60W, are hard wired units for permanent installations.
21. DO YOU OFFER FREE SHIPPING?
We offer free ground shipping for orders above $69.00.
22. HOW LONG DO YOU TAKE TO SHIP THE PRODUCTS?
We offer same day shipping for all orders placed before 11:00AM EST on all items in stock.
23. DO YOU HAVE ANY CATALOGS AVAILABLE?
We don't have any catalogues available. All the products we have are currently online.