Not very happy with LEDs.

[Tony Stewart]

I think October is when the "Cows come home" to see if you fixed it yet.

Whatever you do , you might not want to regulate voltage by the tip of your finger.
You confirmed Audioguru's suspicion of running at peak voltage instead of average rectified.


This is a 1.5 kva transformer that I use for my CNC. I used 100 amp diodes to make the rectifier and the highest mfd capacitors that would fit in the box. The ones on the boat are 6" high & 4" square with a 7 amp fuse.

If it burns your finger , it's too much current

 

[MrAl]

What happens in October?

Hi,

National Energy Awareness Month.

It was also a time period that was distant enough to set as a goal so if it wasnt figured out already we would be allowed to show the solution.
So as Tony noted, it's when the cows come home

 

[ClydeCrashKop]

Okay, If you guys really want to sort this out, here is more info.
I realized later that I didn't finish my LED symbols before copying, pasting & rotating all of them.
Its not worth fixing them all now. Sorry about that.

 

[Tony Stewart]

Falstad Simulation

Most likely fault ...

Florida Power Line transients
causing blown diodes from insufficient PIV, line filter and MOV.

Not recommended for Florida.
Florida has the highest frequency of lightning in the United States.

Jacksonville

• 
  
  
  • Last update: 1.2 minutes ago
  • Last detected stroke: 2016-09-01 13:24:17 UTC
  • Current stroke rate: 19.2 strokes per minute
  • Storms often peak at 180 strokes per second in a region .. not to one home.
  • 

 

[Tony Stewart]

next

 

[ClydeCrashKop]

Florida Power Line transients
causing blown diodes from insufficient PIV, line filter and MOV.

Not recommended for Florida.
Florida has the highest frequency of lightning in the United States.

Ha Ha That explains a lot!
Thanks Tony

 

[Tony Stewart]

What's the failure rate being seen?

 

[ClydeCrashKop]

We got 140 of these from West Marine. 30 or more burnt the rectifier diodes and stunk and quit. At least 7 of them blew the 7 amp fuses.

 

[Tony Stewart]

Is that 30/140 failure Rate? Do you want a solution or just a better product? Where installed? with above ground power lines? On a yacht or in marina?

 

[ClydeCrashKop]

They are installed on a 86 ft Hatteras yacht at a private house on a canal. They went out one at a time. We consider these a fire hazard and are replacing all of them. I think we have better ones now that cost 1/3 as much as the bad ones. We will see.

The price here isn't all that important. Mainly, I am just complaining.

 

[Tony Stewart]

Unlikely to be much better without transient protection.


edit...
The type of transformer makes a difference how much coupling capacitance it has for transient impulses. Even though the transformer is 120:24 or 5:1, impulses may couple thru at a higher ratio with no capacitive load before the diodes. The 4 SMD diodes are often only rated at 70V or 100V which seems adequate for 24Vac but not ?kV transients.

Thus it depends on the transformer coupling C which means it can be attenuated with a plastic cap across the transformer output and serve all the lamps.

 

[RODALCO]

SMD 's are rubbish for this type of application. A set of 1N4007 (1Amp) or 5408 (3Amp) diodes are the better option for rectifying the 120 or 240 Volts mains.

 

[Tony Stewart]

24V AC transformers are often thought as low voltage but with unbalanced loads on loop circuits and transformer xxx pF coupling can pick up significant transients from nearby lightning.

 

[Tony Stewart]

If replacing, I would also add 40V range for minimum clamp level bipolar TVS clamps across each transformer 24vac output. with .CA suffix as voltage peak will be 24*1.4 at full load and add 10% for almost no load (LED) or +/- 37Vp ... assuming this is your situation.
Low cost avail from Digikey , Mouser best bet.

https://www.farnell.com/datasheets/1725637.pdf

 

[ClydeCrashKop]

Thanks Tony. I will do that.

 

[Robert Sumner]

We got some 24 volt LED rope lights for under the stairs. I replaced the incandescent strings on 2 stairs. 3 months later, more incandescent strings went bad so I replaced the rest of them. With only occasional use, the LEDs that I had already replaced were a lot dimmer than the new ones from the same spool. So I replaced those 2 strings again and told the captain not to use them unless the owner was onboard.

Hi,

I'm only a student of electronics but recently read a later unit on oscillators, nearing the end of the course.

I'm just a little curious as to how wiring goes aboard a ship.

Does the ship use only 60 Hz AC power or do you have to convert it for a typical application such as lighting?

 

[Tony Stewart]

Marine generators come in all sizes and shapes and country of origin tends to match the equipment in that country e.g. 230V 50Hz or 120V 60 Hz or Japan 100V etc.

The "oscillator" here is the reciprocal engine and generator.

 

[ClydeCrashKop]

This 86 ft. Hatteras yacht has 2, 1800HP MTU engines, 24 volt.
2, 35KW Onan generators, 24 volt starting & controls, 115/230 volt 60 Hz output.
The navigation electronics are 24 volts DC from the batteries.
Lighting in below decks hallway & machinery spaces are 24 volts DC from the batteries.
The engine room also has 115v. fluorescent lights.
All other lighting is decorative 24 volt AC (now rectified) from 115 volt transformers.
(That is a mirror on the ceiling & an EL light around it.)

Smaller boats & ones without generators, are usually 12 volts DC with some 115 v. lights for while docked. There are refrigerators that run on both. Some mega-yachts have 230 volts 3 phase.