Lights keep blowing

Discussion in 'Lighting and Electrics' started by Joey Brown, Jun 1, 2016.

  1. Joey Brown

    Joey Brown New Member

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    Hi, I was wondering if any of you could help me with an issue I have with my lights system.

    For the past several months I've had an issue where the breakers on our Leprecon dimmers keep flipping. in addition to this the bulbs themselves ( standard 575 watt bulbs ) would blow. We thought it might be the dimmers have gone bad ( They are rated for 1800 watts, and we have about 1725 max on one dimmer ) since they are 10+ years old, so we tried replacing all of our dimmers, which fixed some of the problem, but there is still one dimmer that keeps flipping, as well as bulbs that keep blowing through out the system. We are not sure what could be the issue, but any suggestion is welcome.
     
  2. TJCornish

    TJCornish Well-Known Member

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    Have you measured your facility voltage? Are you using 115v or 120v lamps? Standard or long life? How heavy are you loading your dimmer channels? Product models in question? 1725w on an 1800w dimmer with a slightly high voltage could definitely cause the issue, as well as short lamp life.
     
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  3. lwinters630

    lwinters630 Well-Known Member

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    There are several things to check. When a bulb blows, often it will trip a breaker. If breakers trip and no blown lamp try only putting two fixtures on the breaker. When turning on a dimmer the draw can exceed the amp rating and cause a trip. Length and size of cable will add amp draw.
    Check inside the fixture socket, look for burning or black. The contacts on the bulb may also show burning. This will cause the lamp to fail. Change socket.

    If breakers continue to trip, swap dimmers. If it continues, open up the electrics race, start at recepticle look for loose or bad connections/wires. Replace as needed.
     
  4. TJCornish

    TJCornish Well-Known Member

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    Nope - length and [smaller] size of cable in a resistive application will REDUCE current draw. Burnt lamp sockets will definitely affect bulb life, but won't trip breakers.
     
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  5. JD

    JD Well-Known Member

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    Correct!
    When dealing with resistive loads, like conventional lamps, the longer cable reduces the load by adding resistance which lowers current draw.

    As said above, lamps blowing will often trip a breaker. So, here's what I would check:
    Building voltage and the rated voltage on the lamp. If you power company made changes in the area, your line voltage may have gone up. Not uncommon these days to have line voltage at 127 volts. If your lamps are 115, then this will eat lamps. Some dimmers (ETC comes to mind) will compensate for line voltage variations, but most will pass the higher voltage (less the dimmer inefficiency) right to the lamp. If you have a known condition (like 115 volt lamps and 130 volt mains) you could simply make sure your board settings never exceed 90%.

    There are other things that could cause the problems you are experiencing. It all depends on how the lamps are blowing. I would have an electrician go over your neutral line to make sure it is solid. A loose neutral can cause voltage spikes that far exceed the lamps rated voltage. Some neutral issues may be outside the building (electric company) and may only show up on windy days or some other special times, but at least you can check what is inside the building. Make sure the electrician does some lopsided load tests. If a heavy load on one leg causes another leg to spike outside of reason, then there is your problem.

    In general, your dimmers are not your problem, although replacing them with dimmers that do self regulation may actually cover up a more serious issue while making things look like they are "fixed."
     
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  6. Joey Brown

    Joey Brown New Member

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    Well, we've had electricians come out and everything tested normal. We've replaced the sockets and bulbs but the problem continues to occur.
    bulbs blow > replace bulb > sockets blacken > replace socket > bulbs blow (occasionally one of the breakers on the dimmer pack itself will blow)
    and that cycle is on constant repeat. I'm not sure what to tell the next electrician that comes out since every time they do come out the system checks normal.

    Is there a good starting point? or at least something I can tell the next electrician that comes out?
     
  7. sk8rsdad

    sk8rsdad Well-Known Member Premium Member Fight Leukemia

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    You could ask your electrician to try installing a power logger to see if you've got a general power problem. Most loggers can record anomalies like brownouts and voltage spikes. If you're over-voltaging that can dramatically reduce lamp life.

    However, blackened sockets suggest arcing which suggest a contact issue, which suggests the lamps and sockets don't belong together. Perhaps the lamp manufacturer could help you analyze why they are failing. Maybe the lamps aren't being seated all the way when they are relamped. Maybe it's a manufacturing tolerance problem. The blackening and pitting patterns can provide a lot of information to an experienced person. All this assumes your lamps and sockets are not some sort of knockoffs from eBay.
     
    Last edited: Jun 1, 2016
    RonHebbard likes this.
  8. TJCornish

    TJCornish Well-Known Member

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    What exactly did they test? You need to know the voltage at the dimmer pack, and if possible, at the socket of the lamp when it's on with lamps burning. If you are using 115v-rated bulbs and you're metering 123v at the socket - that's a problem - both for lamp life, and tripping breakers.

    When you say "blow", does the filament break or does it stop working because the socket is arcing? I agree with sk8rsdad that if you're having this problem repeatedly, you've either got a bad batch of bulbs or a bad batch of sockets.

    What fixtures are these? How long does it take to go? Is only the one fixture blowing bulbs? All of them on this dimmer? All of your fixtures?

    You still haven't answered earlier questions about dimmer, bulb, and fixture models.
     
  9. Joey Brown

    Joey Brown New Member

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    The following is a list of what we use in our system:

    - We have 5 Leprecon ULD 360 Dimmers ( only one has been giving us issues since we replaced them, but before it was all five)
    - the ellipsoidal we use are Leviton Leo Ellipsoidal spotlights ( we have 24 total, but not all of them have blown )
    - The fixtures use Standard 575 watt bulbs we get from a local electrical supply store. ( picture of bulbs are attached)

    When I say blow I mean the filament breaks, usually it is completely melted and there are scorch marks on the glass casing. The bulbs have lasted from several months to a few days, it seems to be a random occurrence as to when they blow.

    the dimmers are brand new, but the lights are several years old. We have replaced the sockets in a lot of them, but they still blow regardless.
     

    Attached Files:

  10. TJCornish

    TJCornish Well-Known Member

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    Might be time to look into 120V bulbs instead of 115V bulbs. Also might be time to find a real theatrical supplier that can guarantee a name-brand lamp and matching sockets.

    FWIW, a few months for a standard-life bulb is perfectly reasonable - most are rated at 300 running hours.
     
  11. Joey Brown

    Joey Brown New Member

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    I actually just called Leviton, the producer of our fixtures and thats what they recommended. We're gonna look into that and hope it works.
     
  12. JD

    JD Well-Known Member

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    Didn't see it mentioned, so I will- When you have a bad socket or scorched pins on the lamp, you have to replace both at the same time! Bad pins on the lamp will wreck a new socket, a bad socket will wreck a new lamp, so always replace both when either is found.
    Still, the failure you describe sounds more like over-voltage. Having the load testing is important because many problems will not show until there is a substantial load on the system.
    What brand are those lamps? (I don't see anything on the base) I know there are a couple of off-market brands from India that are pretty inexpensive, but don't last. Even quality manufacturers sometimes have problems with a batch. Always best when having these problems to make a lamp log and try to record the batch numbers off the carton. Sometimes a little detective work is needed!
     
  13. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Interesting that the filament geometry of the FLK pictured doesn't look any different than that of an EHD or EHG. But, FLK's are notoriously known to fail prematurely due to vibration or rough handling (or even gentle handling while focusing), which is why we almost always suggest something from the GLC, GLA, GLD, GLE family.

    I want to know the voltage at the lamp socket. Put a twofer at the fixture. With the dimmer at full, measure voltage at the empty female and tell us what it reads.

    IF you're running 3x 575W, 115V on one dimmer, and supplying them with say, 125V (unlikely but possible), your load is actually 1971W and 15.8A, which one would think would not trip a 15A breaker, but I've found the Leprecon ULD breakers to not like anything more than 1150W per channel. Actually that 15A-1800W is shared across three ULD dimmers. One lamp on each dimmer=fine. One lamp on two dimmers and two lamps on the other dimmer (four lamps total), all three dimmers at full trips the "main" breaker on the pack.
     
  14. DavidNorth

    DavidNorth ETC Rigging General Manager Premium Member Fight Leukemia Departed Member

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  15. Joey Brown

    Joey Brown New Member

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    hey guys!

    Since we thought the issue was too much voltage we tried lowering the intensity of the lights on our main service clip from 100% to 85%, lowering the voltage. During the Sunday service, when the bulbs usually blow, we had none go out. We think the issue was just too much voltage for the bulbs to handle. Hopefully that fixed it, thanks for all the suggestions!
     
  16. TJCornish

    TJCornish Well-Known Member

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    What did you measure? If they blow so often that you expect failures every week, you may have a significant problem. You NEED to measure your voltage as requested above.
     
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