Hello, is there a reason why many manufacturers stick with 12V AC for the pool lights instead of the 12V DC? One of my 12VAC transformer failed, can I use a 12V DC?
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Pool Light 12V DC vs 12V AC
- Thread starter Gepool
- Start date
They are using 12v ac for the same reason we us alternating current in homes, industry, etc. For one, DC current diminishes much more quickly over distance than does AC.
- The AC is simpler to produce than DC. It is also less expensive than DC to generate.
- The AC systems have higher efficiency than DC such as ac generators.
- The waste of power is negligible for AC during transmission.
From exprerience with LED bulbs, most of them that I use in my various projects works both 12V ac & 12V dc since they have an embeded rectifier bridge.The quick and dirty answer is "No". They're not interchangeable.
Maddie
Is 12V AC safer that 12V DC? I am just trying to understand the difference.
Its not the voltage but the amperage you need to fear. You can hold a spark-plug wire that hits you with 40,000 volts (DC) and it will hurt like crazy, but won't necessarily harm you (been there.) The actual current is milliamps (one or two thousandths of an amp).
A lethal shock can be as few as .06 (six-hundredths) of an amp at any voltage AC or DC. That's why we do everything possible to keep electricity out of the pool water.
A lethal shock can be as few as .06 (six-hundredths) of an amp at any voltage AC or DC. That's why we do everything possible to keep electricity out of the pool water.
So, the main reason choosing 12V AC is for delivery, efficiency and economy as you suggested, and not for extra safety. Do I get it correctly?
(if that translates well into Greek.) Plus you don't really get a choice.
G,
Safety wise, the transformer that turns the 120 volts AC into 12 volts AC is "pool rated". This means it is designed so that if it fails, the 120 Volts can't get into the 12 volts side and into your water.
The 12-volt DC units you see are not pool rated as they usually use switcher pool supply to convert the 120-volt AC into 12 volts DC. If they fail, they can allow the 120 to get over to the 12-volt side.
Thanks,
Jim R.
Safety wise, the transformer that turns the 120 volts AC into 12 volts AC is "pool rated". This means it is designed so that if it fails, the 120 Volts can't get into the 12 volts side and into your water.
The 12-volt DC units you see are not pool rated as they usually use switcher pool supply to convert the 120-volt AC into 12 volts DC. If they fail, they can allow the 120 to get over to the 12-volt side.
Thanks,
Jim R.
If DC diminishes much quicker over distance than AC, why are the longest transmission lines DC?
No that is true. The most famous example (here on the west coast) is the Pacific Intertie
In fact for a given voltage, conductor and amount of power the losses are the same whether DC or AC. The reason that AC is preferred for power transmission is that you just need a transformer to step up the voltage up or down, and higher voltage is the main secret to transmitting electric power long distances in an efficient matter. Whereas for DC it requires much more expensive equipment.
Back to the long distance DC lines, if the transmission gets long enough (say from the Washington/Oregon border to Southern California) then you start to have problems from the AC wave reflecting off the far end of the line and causing possibly much higher voltages the the line is designed for. The DC connection also is useful when sending power to two independently operated grids where the AC of one grid is not necessarily in phase with the other.
As for your low-voltage Pool lights I suspect 12 VAC is used just because the needed driver (the transformer) is cheaper. Ironically if the lights are LED then there will be a rectifier in the lights converting the 12 VAC to DC anyway.
fly,
Very interesting, I did not know that, and it was not what I was taught about a million years ago.
Thanks for the course correction,
Jim R.
Very interesting, I did not know that, and it was not what I was taught about a million years ago.
Thanks for the course correction,
Jim R.
