Why does my transformer keep burning out?
My outdoor lighting uses a transformer and when I plug it in, it burns out. I have burned out three 10 watt transformers, can you help
8 Responses
billrussell42
20 Mar 2010
abd o
20 Mar 2010
the lighting transformer connect at series with the lamp
i mean that the red wire( hot ) go in one terminal of TR and the other trminal of TR connect to lamp, the other terminal of lamp connect to black wire
Nick G
20 Mar 2010
You probably have too large a load on the transformer.
i suspect that you bought 10 Watt transformers because all of your bulbs are 10 Watts. What you must do is add up all of the wattage of all of the lights to get the minimum transformer wattage requirement. Your transformer should be able to handle AT LEAST this much, but should be able to handle 10% to 15% more than this. For example, if you have 6 lights each rated at 7 Watts, your minimum transformer need is 6 x 7 = 42 Watts and you should have 6 x 7 x 1.1 = 46.2 Watts to 6 x 7 x 1.15 = 48.3 Watts. All of these will lead you to a 50 Watt transformer because of the transformer Wattages available.
ricky1200
20 Mar 2010
It burns out because the connected load is too high.
Is there a wiring fault? Has this always happened or just recently started?
What is the transformer output voltage? Is it correct for the rated voltage of the lamps?
What is the power requirement of the lamps? Are they connected in series or parallel?
Warren W- a Morm
20 Mar 2010
You obviously have a short. It may be that the wires are shorted somewhere. Or one of the lamp bases may be rusted short. You are putting a high load on the transformer- beyond its capacity.
ZORCH
20 Mar 2010
I’ll bet your transformer is waaaayyy too small. For 7 watts, you can light a single bathroom night light. That is not much at all. Go count up your total load, add a comfortable cushion (about 15% sounds good), and then buy the transformer.
artsupremo
20 Mar 2010
Check the voltage supplied to your 10 watt transformer. Voltage supply may be higher than your transformer winding rating.
dmb06851
20 Mar 2010
"You obviously have a short."
Correction; the transformer is being overloaded. The overload MAY be due to a short, or it may be due to something else.
There is a lot more than wattage involved when you select a transformer. You need the proper voltage also.
What voltage does the lighting require? If they are all in parallel, just check the voltage on one bulb. It should be printed on the bulb. Your transformer should match this voltage.
If they are in series or series parallel, it gets more complicated.
Now calculate the wattage required. (10 watts is very low, enough for a few bulbs at most). Add up the wattage of all of the bulbs, and that total is what the wattage of the transformer has to be.
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