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Thread: LED fixtures are fusing my relays

  1. #21
    Join Date
    Apr 2008
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    Ann Arbor, Michigan
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    7,051
    181201-2342 EST

    George Stolz:

    Visualize79 in his original post stated a problem, and he probably correctly concluded that fusing occurred as a result of a problem at turn on or off.

    He could have run some simple experiments that might have indicated whether it was a turn on or turn off problem.

    Then what? If no knowledge or equipment, then it is simply a long experimental trial and error process. Guesses of what to try.

    It is probably self-evident that a sufficiently large relay would solve the problem. Without more information it is quite difficult from a remote location to guess at possible solutions. If Visualize79 does not know what is inside his components, and how these electrically perform, then he is left with trial and error.

    Electricians are going to be confronted more often with new devices using electronic components, and internally complex circuits. More experience and knowledge will be needed.

    There are quite possibly some ways an ice-cube could work, but I won't get into those. I think there are other reasons an ice-cube should not be used.

    .

  2. #22
    Join Date
    Dec 2010
    Location
    Tennessee NEC:2008
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    4,845
    Gar,
    Shouldn't your time/date stamp 181201-2342 EST, actually be 180101?
    If you aim at nothing, you will hit it every time!

  3. #23
    Join Date
    Dec 2017
    Location
    minneapolis mn
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    7
    Quote Originally Posted by Fulthrotl View Post
    a quick and dirty that will probably work is RIB. 20A. contacts. latching. 12v secondary momentary contact.

    https://www.functionaldevices.com/pr...tails/RIBL12B/

    this one's 30 A. @ 300V.

    https://www.functionaldevices.com/pr...ails/RIB12P30/
    Thanks man, I'm gonna be checkin those out


    Sent from my iPhone using Tapatalk

  4. #24
    Join Date
    Oct 2007
    Location
    Piedmont region of NC
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    757
    Quote Originally Posted by gar View Post
    181201-1626 EST

    myspark:

    You are describing the welfare state. Provide someone a handout.

    This is the old fish story. A hungry person needs food. You can give him a fish, that is good for one meal. Teach him to fish and he can live without further handouts.

    We are not where the problem is, and we can't directly make measurements to try to find the cause. From our remote position we can only guess.

    Many people in many fields are encountering new products. We need to learn how these products work if we are to be efficient in troubleshooting problems.

    Screw-in LED replacrements for incandescent bulbs present all sorts of problems, such as --- RFI (radio frequency interference), flicker, dimmability, intermittent on-off, light quality, degradation of light with time, reliability, initial inrush current, repetitive in rush current, ambient temperature, and operation in a confined space. One needs to known about details that were not needed with an incandescent.

    A big enough relay will probably solve the problem. That is the easy remote answer. Is that the best solution?

    .
    Hello Gar,

    Thank you for the timely info. You mention all of the problems associated with screw-in LED replacements. Is this the same for the T8 replacements that bypass the ballast?

    Best,
    Ravenvalor
    Electrical Contractor
    Piedmont Region of NC

    "Good day and good premises." (Ayn Rand)

  5. #25
    Join Date
    Oct 2007
    Location
    Piedmont region of NC
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    757
    Quote Originally Posted by Fulthrotl View Post
    a quick and dirty that will probably work is RIB. 20A. contacts. latching. 12v secondary momentary contact.

    https://www.functionaldevices.com/pr...tails/RIBL12B/

    this one's 30 A. @ 300V.

    https://www.functionaldevices.com/pr...ails/RIB12P30/
    Maybe OP can try just one of these and see how it does. I wonder it the contacts on this relay are much larger and spaced further apart compared to his ice cube relay.
    Ravenvalor
    Electrical Contractor
    Piedmont Region of NC

    "Good day and good premises." (Ayn Rand)

  6. #26
    Join Date
    May 2017
    Location
    SCV Ca, USA
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    414
    Quote Originally Posted by gar View Post
    181201-1626 EST

    myspark:
    You are describing the welfare state. Provide someone a handout.
    This is the old fish story. A hungry person needs food. You can give him a fish, that is good for one meal. Teach him to fish and he can live without further handouts.
    We are not where the problem is, and we can't directly make measurements to try to find the cause. From our remote position we can only guess.
    Many people in many fields are encountering new products. We need to learn how these products work if we are to be efficient in troubleshooting problems.
    Screw-in LED replacrements for incandescent bulbs present all sorts of problems, such as --- RFI (radio frequency interference), flicker, dimmability, intermittent on-off, light quality, degradation of light with time, reliability, initial inrush current, repetitive in rush current, ambient temperature, and operation in a confined space. One needs to known about details that were not needed with an incandescent.
    A big enough relay will probably solve the problem. That is the easy remote answer. Is that the best solution?

    .
    The “fishing” analogy seems to ring hollow. Not only that it does...it also sounds offensive to insinuate that whoever request for advice (electricians or others involved in electrical work) that don't possess the knowledge that you expect are akin to people destitute enough to beg for handouts.

    The hierarchy of any organization always has a chain of command to make for an organized entity.
    We can't be all electricians as much as we cannot be all engineers.

    The concept of having to know all there is to know about the electrical trade is an untenable goal. . . even a pipe dream.

    Someone has to work behind a desk and someone has to do the “dirty” work. . . and whichever that individual chooses is clearly defined how good he is in performing the job. It is comforting to see a topnotch electrician than to see one lousy engineer.

    It is good to have some sort of diversity ie knowing a bit of (almost) everything and not be subjected to be demeaned because a person lacked the knowledge of empirical formulas.

  7. #27
    Join Date
    Apr 2008
    Location
    Ann Arbor, Michigan
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    180102-1222 EST

    Little Bill:

    You are absolutely correct I was way off. It takes time to get used to a new year, and then I will still make mistakes. I can not proofread myself very well, even when I try.

    I had suggested a simple means to estimate peak in-rush current with a current shunt (a small resistance value), diode, capacitor, and DVM.

    This morning I ran an experiment using a 9W Cree LED, a 2 ohm current shunt (current measuring resistors are called shunts), a diode similar to a 1N4004, a 25 ufd capacitor, and a scope. The largest scope peak voltage was about 8 V, and the DVM reading was close to 6 V. Peak current calculated from the scope is 16 A from a measly small LED.

    Whatever total series impedance from the pole transformer thru the 2 ohm and bulb will determine the maximum possible peak current. If we had a zero impedance except for the 2 ohm resistor from a 120 V source that peak would be about 85 A. A 2 ohms shunt is way too high if you want to look at a much lower impedance load. But using the diode method you should probably want to have peak meter readings in the 5 V range.

    Measuring peak in-rush to a single fixture would be a good approach, then multiply by the number of fixtures. This should be an upper limit on the peak in-rush for the X number of fixtures.

    Still using the 2 ohm shunt and a 4' Costco 2 tube LED fisture the scope read a maximum peak of 20 V, or 40 A at turn on. Nominal measured power of the Costco at 125 V is 37 W.

    A P&B KUP 10 A AgCdO contact is rated 5 A for tungsten load. I don't know the number of cycles this rating is for. It is not 1,000,000, possibly not even 100,000. Estimate peak current at times for a 5 A tungsten is 64 A.

    .

  8. #28
    Join Date
    Jul 2007
    Location
    Clark County, NV
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    Quote Originally Posted by gar View Post
    ...This is the old fish story. A hungry person needs food. You can give him a fish, that is good for one meal. Teach him to fish and he can live without further handouts...
    Build a cold man a fire and you only warm him for one day. Set him on fire and you warm him for the rest of his life.

  9. #29
    Join Date
    Feb 2003
    Location
    Bremerton, Washington
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    7,961
    Some panel mfgs (Sq D for one) make circuit breakers that have solenoid/remote control operators. Certainly would be able to carry your LED current.
    Moderator-Washington State
    Ancora Imparo

  10. #30
    Join Date
    Dec 2017
    Location
    minneapolis mn
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    Quote Originally Posted by MAC702 View Post
    Build a cold man a fire and you only warm him for one day. Set him on fire and you warm him for the rest of his life.
    That's cold


    Sent from my iPhone using Tapatalk

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