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Eiko t8 led typeB

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  • sameguy
    replied
    [QUOTE=Dennis Alwon;1995138]The first thing I want to know is why there are unqualified people opening these fixtures?"

    Because they cost less than qualified.

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  • Dennis Alwon
    replied
    The first thing I want to know is why there are unqualified people opening these fixtures?

    Most kits that I have seen come with stickers that need to be installed but these are 120v units.

    Leave a comment:


  • kevin.luce@matsuk12.us
    replied
    Is there an update to this project? I work for a large school district and one of our new electricians ordered a lot of tombstone kits and type B lamps. We have never done type B lamps due to the mains voltage at the tombstone (non qualified personnel routinely are in the fixtures). Has this ever been a liability concern, safety issue or as a code issue and are we violating the UL listing by modifying the fixture with separate components vs a kit? Any input would greatly appreciated before we change direction in our retrofit program.

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  • Mparn
    replied
    Update on our project.

    Starting in February and completing in July, we have replaced approx. 5,000 lamps and decamped around 2,000. I know its early but here are some notes from the project.

    Everyone seems to like the overall quality, consistancy, and level of lighting. It seemed a little bright for some at first, most of those rooms had several lamps out.

    We've had a few issues; 1 lamp went bad, 2 lamps where the wire came loose, and 1 lamp was not put in correctly.

    Our district has avgerged around 1.6 mil kWh per year over the last 3 years. We are on pace to end the year at 1.2 mill kWh. That should be around $40,000 in savings. I also adjusted the summer HVAC schedule, which also played a role in reduction.

    Over the next month I will be replacing the exterior lighting. This includes; shoeboxes, flood lights, and wall packs. Each exterior fixture will have it's own surge protector.

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  • Kinexis
    replied
    Originally posted by Mparn View Post
    Our building were built in 1988 and 1999. Thanks for the info on the magazine, I'll look into that.

    Kinexis, are you concerned with 277 at the sockets?

    no, i would put warning stickers on them though. say something like "DANGER 277Volts at tombstones, site policy is to de-energize light before servicing", or "De-energize or light will be damaged when servicing".

    and also make sure everything is rated for it, the wire may be good at the high voltage only for start-up and not for continuous operation at the voltage i don't know though, just throwing it out there because i would look into it if i was going to do that

    i always thought you should de-energize a light when changing lamps anyways, when you put it in unless you do it perfectly you can connect and disconnect and then reconnect which i think is very hard on lamps of any kind especially new ones. plus there hot and you might be more likely to drop it.

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  • LarryFine
    replied
    Originally posted by gar View Post
    In tubes with two pins per end and a small heater electrode at each end, the earliest fluorescents, a preheat circuit including what was called starter was used to lower the initial breakdown voltage.
    I have plenty of experience with starter-equipped fluorescent lights, and even have modified them with momentary switches to eliminate the starter. N.O. push-buttons to start the lights, and N.C. to extinguish them.

    I've been doing electrical work for fifty or so years. I'll be 63 next month, and I did my first service upgrade when I was 15. I added a generator and T/S years later, and critiqued my own work. Proud to say I did everything correctly.

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  • gar
    replied
    180429-2206 EDT

    LarryFine:

    For a cold cathode tube, mono end electrodes, it takes a relatively high voltage, 600 to 1000 V, to initiate ionization of the gas. After initiation of ionization, then the arc voltage drop is relatively low. The power source to the tube must be of a current limiting nature. High leakage inductance in the transformer.

    Once a tube has been initiated the mono electrodes become fairly hot from tube current and the initial breakdown voltage per half cycle becomes less.

    In tubes with two pins per end and a small heater electrode at each end, the earliest fluorescents, a preheat circuit including what was called starter was used to lower the initial breakdown voltage.

    .

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  • LarryFine
    replied
    I've always been under the impression that fluorescent ballasts have outputs up to 600v OC.

    Added: http://www.electrical101.com/fluorescent-ballasts.html

    Leave a comment:


  • Mparn
    replied
    Our building were built in 1988 and 1999. Thanks for the info on the magazine, I'll look into that.

    Kinexis, are you concerned with 277 at the sockets?

    Leave a comment:


  • Kinexis
    replied
    i'm not finding anyone else addressing it in this forum, but there was discussion over concern of 277v at the tombstones, don't most fixtures like the op currently has have lamp start voltages of several hundred volts at the tombstones? when you install or remove a lamp on an energized fixture you are exposed to that voltage, your exposed when you remove because you can easily disconnect and accidentally reconnect. or is the secondary of most ballasts not grounded?

    Leave a comment:


  • Kinexis
    replied
    i recommend trying the new led's in various parts of the building's for a period of time (honestly i would test for a year before replacing that many) before replacing everything with LED, there has recently been an article series in EC&M magazine about ground planes for LED drivers that talks about some of the issues coming up with LED's especially in older facilities. i would think you would have decent bonding throughout the buildings but i would test before committing to all LED. i have seen several facilities that have kept replacing LED's and i suspect it may be related to the issue discussed in the articles in EC&M, they were older facilities and not very well wired to begin with.

    Leave a comment:


  • gar
    replied
    180428-1146 EDT

    Mparn:

    I would like you to run an experimebt if you can.

    I took my only LED fixture, a 4 ft twin tube Costco shop light, and with a Powerstat (variac) adjusted the input voltage from 70 to 140 V with a GE light meter monitoring the light intrnsity and saw virtually no intenity variation.

    Do you have any way to change the AC sine wave voltage to one of your fixtures? If so, then even a visual observation may tell us whether the light output is particularly sensitive to voltage.

    In contrast I can take a Cree screw-in 9.5 W bulb and get good dimming control with a variable sine wave voltage source.

    .

    Leave a comment:


  • gar
    replied
    180427-2131 EDT

    Mparn:

    My two bulb experiment is not as good as I would like. The high current pulse generated by randomly turning on an incandescent (I used 75 W for convenience) does not have an adequately high probability of having its maximum value and longest duration as compared with a controlled turn on at the voltage peak. I could barely detect the transient pulse compared to the steady state change.

    For an illustration of incandescent turn on current see my photos P1 thru P4 at http://beta-a2.com/EE-photos.html .

    In doing this experiment the bulb being turned on should be totally out of view. Do not look directly at the always on bulb. Shine it on a wall or use something to greatly attenuate the brightness.

    Do not view what I am describing as over your head. Think about it and ask any questions. You seem to have a great interest for looking into why things you see occur.

    .

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  • Mparn
    replied
    Originally posted by gar View Post
    180427-1005 EDT

    Mparn:

    At this point you need to define some words and run some independent experiments.

    Flicker could means a number of different things. Is it a single shot event? Does it means 120 Hz ripple on light intensity? Not in your case, but it did in [COLOR=#000000]Russs57's comment. Does it mean an increase in intensity, or a decrease? Is it a short duration oscillation in intensity? Or etc.

    [/COLOR]Consider two 120 V switched 100 W bulbs fed from the same phase and sharing a common neutral of 10 ohms. A cold 100 W 120 V incandescent bulb is about 10 ohms, and hot about 144 ohms. With one bulb on its voltage is about 120*144/154 = 112 V. You would see a brightness difference in the bulb compared to a circuit with a much lower neutral resistance.

    I have selected the bulb size and neutral resistance such that you can easily experiment. 100 W incandescent bulbs are still around, and a moderately stable resistance at 1 or 2 A and somewhat near 10 ohms is the resistance of a 1500 W space heater.

    At the instant the second bulb turns on the voltage across the two bulbs is about 120*10/10 = 60 V. Actually a little less because you have 144 ohms shunting 10 ohms, or 9.35 ohms. So you will see a short time flicker in the dimming direction of the initially on bulb.

    Now suppose the two bulbs are supplied from opposite phases. The 10 ohm neutral initially has a voltage drop of 120*10/154 = 7.8 V with one bulb on. At the instant that the second bulb is turned on two opposing currents exist in the neutral. Doing the math just after the second bulb is turned on I get a voltage drop across the 10 ohm resistor of about 54 V. This is in a direction to add voltage to the initially on bulb so that the already on bulb sees about 120 + 54 = 174 V. Thus, the already on bulb brightness momentarily increases a lot, bright flash.

    When the turning on bulb reaches its high resistance the 10 ohm resistance has a voltage drop of about 0 volts, canceling currents thru the neutral, and the initially on bulb is slightly brighter than when it was the only load. You may not detect this.

    The above is a suggested experiment that I have not played with but may illustrate how neutral impedance can affect components in a circuit.

    LEDs have ballasts (power supplies) that may be pretty much like an uncharged capacitor at their input before turn on. Connecting an electronically ballasted LED at a voltage peak and large peak currents may flow.
    Gar,

    Thank you for all your help. Although you are way over my head, you have explained it to where I am able to understand. By "flicker" I mean, a single shot, one time, where the light dims or goes out. It happens really fast but you are still able to see it. You have to actually study it to see that it's dimming and not getting brighter.
    Last edited by GoldDigger; 04-27-18, 06:32 PM. Reason: fix /QUOTE tag

    Leave a comment:


  • gar
    replied
    180427-1005 EDT

    Mparn:

    At this point you need to define some words and run some independent experiments.

    Flicker could means a number of different things. Is it a single shot event? Does it means 120 Hz ripple on light intensity? Not in your case, but it did in [COLOR=#000000]Russs57's comment. Does it mean an increase in intensity, or a decrease? Is it a short duration oscillation in intensity? Or etc.

    [/COLOR]Consider two 120 V switched 100 W bulbs fed from the same phase and sharing a common neutral of 10 ohms. A cold 100 W 120 V incandescent bulb is about 10 ohms, and hot about 144 ohms. With one bulb on its voltage is about 120*144/154 = 112 V. You would see a brightness difference in the bulb compared to a circuit with a much lower neutral resistance.

    I have selected the bulb size and neutral resistance such that you can easily experiment. 100 W incandescent bulbs are still around, and a moderately stable resistance at 1 or 2 A and somewhat near 10 ohms is the resistance of a 1500 W space heater.

    At the instant the second bulb turns on the voltage across the two bulbs is about 120*10/10 = 60 V. Actually a little less because you have 144 ohms shunting 10 ohms, or 9.35 ohms. So you will see a short time flicker in the dimming direction of the initially on bulb.

    Now suppose the two bulbs are supplied from opposite phases. The 10 ohm neutral initially has a voltage drop of 120*10/154 = 7.8 V with one bulb on. At the instant that the second bulb is turned on two opposing currents exist in the neutral. Doing the math just after the second bulb is turned on I get a voltage drop across the 10 ohm resistor of about 54 V. This is in a direction to add voltage to the initially on bulb so that the already on bulb sees about 120 + 54 = 174 V. Thus, the already on bulb brightness momentarily increases a lot, bright flash.

    When the turning on bulb reaches its high resistance the 10 ohm resistance has a voltage drop of about 0 volts, canceling currents thru the neutral, and the initially on bulb is slightly brighter than when it was the only load. You may not detect this.

    The above is a suggested experiment that I have not played with but may illustrate how neutral impedance can affect components in a circuit.

    LEDs have ballasts (power supplies) that may be pretty much like an uncharged capacitor at their input before turn on. Connecting an electronically ballasted LED at a voltage peak and large peak currents may flow.

    .

    Leave a comment:

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