I need to power a large 180W LED lamp that runs on DC so I got this transformer that is 12v × 15amp. But I don't understand the labeling on the terminals.
- There are 2 +V terminals but no -V terminal, why?
- What is the 'com' terminal for and why 2 of them?
- What is that terminal between 'com' and 'N'? I'm guessing ground.
- What grade/gauge/type of wiring must I use for safe and efficient
operation? - Any additional equipment devices needed for safe operations?
- What is the purpose of 'output adjuster' knob? There is a knob in
the corner but it doesn't look like it can be adjusted by hand. What
kind of tool is needed here? See image below.
My aim is to use AC from the wall and turn it into DC to supply the LED. Please show me the correct path lest I get electrocuted. Somebody told me the 'com' terminals are -V output and said there are 2 of each -V/+V so you don't have to jam a thick wire in and instead use two smaller wires. This is a bit confusing. Please elaborate and whether this step is even necessary.
- If 2x -V/+V terminals present, is total current/voltage split
between the two? Can I use just one set of terminals to get full
voltage & current, or must I use both? What happens if I use just
one set?
Please help. I don't want to hire an electrician for a job that may be very easy. Neither the LED nor the power supply came with any manuals or supporting documents. LED manufacturer said to use the above power supply.
Additional info on power supply,
Link to actual product page
Item description is found at this link
Best Answer
Disclaimer: If you don't know what you're working with, I suggest you hire someone to help. I know it's not what you want to hear but it's better safe than injured or dead. You only get once, maybe twice to seriously mess up.
From left to right on the back:
The AC "L" and "N" probably mean "Live" and "Neutral" respectively. The ground next to it is the Earth ground. The V+ and COM are the DC output terminals, which you could also say are V+ and V-, respectively.
Just some clarification: What you're referring to when you say V- is probably "ground" or to be precise, 0 Volts. With respect to the circuit with the LED anyways. COM and V- and Ground can all mean 0 Volts. However, V- is typically reserved for actually negative voltages, like -10V, etc.
The reason why there is a set of two is probably because there are two "rails." A rail acts as an independent supply so that you can easily isolate or distrubute loads so that two separate circuits don't interfere with each other or rob each other of too much power. This is just a guess since there's zero documentation for this supply. Also without documentation we don't know if it's possible to run those outputs in such a manner you can power the one 180W LED without some other external circuitry.
A lot of high power LED's I've seen run at ~30V or so. Power = Current x Voltage, so 180W = Current x 30V, solved: 6A of current. You'd set the output voltage of the power supply by using the adjust potentiometer "+V ADJ" before connecting anything.
According to the following table you probably need 12 gauge or larger wire (allowing more amperage to over-rate so the wires don't heat up easily).
http://www.powerstream.com/Wire_Size.htm
Also another consideration: Be sure the LED has plenty of heat sinking otherwise it will burn up immediately. Even 20W - 50W LED's can require heatsinks as large as a typical desktop CPU's (including a fan).