How to test led's at masthead??

[thekeip]

OK, Age is catching up with me.

When a Aqua Sig series 40 would come into the yard I used to figure out from the wattage rating of the individual bulbs (Anchor is 10w; Tri is 25w) whether my connections were right re Gnd, and which bulb should be lit when I applied the power to that bulb. Well it's not that easy when the incandesents are replaced with equiv Leds....simple resistance measurements don't work anymore...I think. Am I not seeing the forest for the trees?? What to do??
Howard Keiper
Berkeley

[FSMike]

I hate working on things electric. I just turned them on at night, went on deck and looked up.

[SEMIJim]

Originally Posted by thekeip

OK, Age is catching up with me.

Not really.

Originally Posted by thekeip

... when the incandesents are replaced with equiv Leds....simple resistance measurements don't work anymore...I think. Am I not seeing the forest for the trees??

Nope. You're right. Simple resistance measurements won't work anymore.

Originally Posted by thekeip

What to do??

Apply 12VDC and see what lights up .

Seriously.

Best to run a meter between each proposed pair to make sure nothing's shorted, first. Maybe put a low-amperage circuit breaker in line with your test leads?

Jim

[knothead]

Originally Posted by thekeip

OK, Age is catching up with me.

When a Aqua Sig series 40 would come into the yard I used to figure out from the wattage rating of the individual bulbs (Anchor is 10w; Tri is 25w) whether my connections were right re Gnd, and which bulb should be lit when I applied the power to that bulb. Well it's not that easy when the incandesents are replaced with equiv Leds....simple resistance measurements don't work anymore...I think. Am I not seeing the forest for the trees?? What to do??
Howard Keiper
Berkeley

Are you trying to see why a fixture isn't working or are you trying to test a new installation? I'm a little confused.

If I am trying to figure out why something isn't working, I first test to see if I have power by using a separate bulb with a couple of wires soldered to it. If I have power, I clean the contacts and put a little dialectic grease on them. If it still doesn't work, I figure it's the bulb. I deal with led's pretty much the same way that I deal with incandesents except that the led's are polarity sensitive.

Some of the fixtures have a photo cell, but I don't think any of the replacement bulbs have them.

[thekeip]

Well, specifically the problem is this: the customer brought his boat in for general Pac Cup prep, including replacement of the Aqua Sig 40 Tri-Color incandescent lamps with Led's...brand unknown for the moment. While the mast was down I checked all lamps on the mast and all were good.
Upon reconnecting however, I discovered that I had inadvertently gotten my color coding screwed up...would not be a problem if the lamps were incandescent...I could just figure out which was the ground conductor..more difficult than it seems by checking the respective resistances of the Anchor (10 watt) and Tricolor (25 watt) lamps and go from there. The issue is complicated by the presence of a Strobe. The Tri seems to be connected properly and can easily be seen. It draws 140 ma. The Anchor can't be seen at all (it's drowned by bright ambient light)...it draws 40 ma. My question is: is the 40 ma draw reasonable for the 10 watt? I think it is, and have concluded (inferred) that is working.
Pulling the rig again is not a viable option.
Any ideas??
Howard Keiper
Berkeley

[kd3pc]

dusk? Should be able to see or have someone stand back and see...else it is voltmeter time...

current draw sounds plausible, for the wattage difference...

all the best

[hellosailor]

Howard-
40mA is typical for a single "conventional" LED but a "high power" LED could draw more. 40ma at 12 volts will be less than a half watt of power drain, not ten watts, although perhaps that is supposed to be one LED "equal to" a 10 watt conventional bulb. (I don't think it would be bright enough though.)
With LEDs you have one extra hazard, if the maker has not provided reverse voltage protection, it is possible that hooking one up backwards would incinerate it--very quickly. I'd do any testing at a lower voltage level or check with the maker if in doubt.
How the fixture will behave will depend on what protections and what other circuitry they have built into it, I'd be hesitant to suggest it could "just" be tested as if it were a plain LED alone. You might want to confirm with Aqua Signal directly to find out what their suggestion is, the odds are you aren't the first guy to have this problem.