Control/Dimming Over Volting, Just a theory

[Goph704]

Okay
I have a theory that one of the main houses I work in is Overvolting. At this point it could be overvolting or there could be voltage in the ground, or possibly a hertz drop. Again, I haven't tested anything yet. I'm usually not quick to jump to some of the larger problems but this has been pretty consistent over a two year stretch. My indicators are that we're a five year old house that has a relatively new stock of Strand SL's. We blow though lamps, spending well over twice on lamps in the new house as we do in the old space. Also I notice that a lot of my lamps are burning out from the socket instead of blowing the glass. Some of our bases are now useless because of burnouts. My question is two fold, one is, what is the safest way to check for overvolting ( I have a multi-meter) and two is there any possibility i could be missing. I'm still learning a lot about Three phase systems, and I have no plans of putting my self at risk. I have a little basic installation experience. I'll try and find out what kind of Transformer they have there because I think if they are using an open delta then that might be part of the problem. Just looking for a little input.

 

[Footer]

If you had too much power going to your lamps, you would be blowing lamps. Your not blowing lamps, your blowing bases. This is simply a fact of life. You need to learn how to swap out bases and fix the route of the problem. A lamp base usually costs the same as a new lamp. By just replacing the lamp you are just making the problem worse.

 

[aminorking]

The two reasons I can think of are as follows. Firstly, the lamps are not fully seated in their bases. This may cause arching which could cause damage simmilar to what you describe. Secondly, and unlikly, if due to a lose wire/fitting somewhere the potential difference accross the lamp increased significantly, i.e. if the lamp was put accross two phases (in the UK the maximum potentail differnce between phases if 415V)

How to find the fault?
Firstly, check that lamps are being correctly fitted. Do remember to keep your fingers off the lamps when fitting them (i assume you already know this).

Secondly, does your building have any meters already built into distrobution boards showing phase voltages against neutral (you are looking for maximum potential difference, not RMS readings). These would hopefully provide you with some answers.


Are they high quality lamps? Cheaper economy models may not have the same life as your other lamps. Can you find data for the expected/average life expectance for the lamps? Do they match the life spans that you are getting.


[waffle]
Also, just to clarify what voltage is. Voltage is a measurement of the potential difference between two points. It is usually measured between a phase and neutral (which is tied to ground at the closest transformer). Therefore you can not have a voltage in your neutral(ground) as you have to measure between two places. Edit: Reading this through before I post it, perhaps you neutral is not suffieciently tied to ground, not sure about this though, I m sure that someone else will know more than me.

There could however possibly be something that is causing the potential difference between a phase and neutral to be LESS than what it should be (I assume 110V is what it should be as I believe you are in the states, would be 240V in the UK). This should not damage a conventional latern, only cause it to be of less intensity.

If your frequency was below or above what it should be it would only be by a small amount, and would cause no damage in convential fixtures. If it was very low I believe that you would notice it as other equipment might malfunction.
[/waffle]

Hope that all helps and does not confuse (and is all correct)

 

[derekleffew]

Again, the base is the metal part of the lamp. That which it plugs into is the socket.

...Also I notice that a lot of my lamps are burning out from the socket instead of blowing the glass. ...

Can you clarify what you mean? Sounds like it's not a voltage issue at all if sockets are failing. Is there evidence in the socket and on the pins of arcing (black, carbon-like buildup)? If yes, it's likely lamps are not being inserted properly/fully.

But to answer your question, Are you using 115V or 120V lamps? To measure the voltage at the fixture, plug the fixture into a tufer and set the dimmer at full. While using appropriate PPE and following the safety instructions that came with your True-RMS DMM, measure the AC voltage at the unused female of the tufer. If it's above 120V, some dimmers allow a maximum voltage to be set at the dimmer rack's control card.

The type of transformer and number of hertzs (60) is irrelevant in this case.

 

[DimmerDotCom]

Okay
I have a theory that one of the main houses I work in is Overvolting. At this point it could be overvolting ... We blow though lamps, spending well over twice on lamps in the new house as we do in the old space.

Since you mention Strand SL's, do you have a Strand rack as in a CD80SV. If so, from the default screen on the LCD where it says CD80SV Rack xx, you can press the up arrow and cycle thru some readouts including the phase voltages. If it's 120 or below you should be fine. If its above 125 during the middle of the day you may have trouble as your power may drift high during evenings and weekends when power demand is lower.

Are any of your failed lamps glass metalized?

Strand SL's have super tight sockets. Sometimes you need a very good push in using quite a bit of force on the bulbs base. Show us a picture of some of you bulbs inserted into their sockets.

 

[Goph704]

Real quick

1. Footer: I couldn't agree more, since that has been the accepted cause of the problem for the past two years. However on a recent show I discussed with another in town designer about the performance of his stock of SL's, which were purchased at roughly the same time as my stock of SL's he has no similar problems with bases or burnouts. Both of us use FEL 575's in our stock and from what I can tell his stock is maintained about the same as mine. I've been secretly swapping out FEL's for GLA's over the years but the problem still arises. I've also metered out a lot of the "Problem" bases personally and they seem to be functioning well. There is very little charring in the bases, but sometimes the bases do not function. Perhpas "burn out" was the wrong word, My appologies.
2. Aminorking: Again, first impulses as well. I've discovered with most of the SL's there is actually a little click in the socket when the lamp is seated correctly. So I've been very careful for a while to make sure that there is good connection between the socket and the base. Checking for a loose neutral or voltage in the ground would be my next logical step. I do not know if there are meters built into the distribution boards, but I will check that before i even grab my meter.
3. Derrick: Thank you for the correction, There is no black charring on the bases. What's happening is the Pin on one side of the base of the lamp seems to be corroding; while the other is still in new condition. I am using 115 volt lamps. Mostly FEL's Some of which are GLA's We also Use CYV's in our Fresnel's which seem to be fine. The problem mostly arises in Our Altman Star Par's and in our SL's but the Cyv's are lamped at a thousand watts while the Par's and the SL are lamped at 575. I wasn't sure if the Hertz was relevant but I thought I'd ask anyway.
4. Dimmer: We do have a CD80 I will check that next time I'm in the space. This space is tied into the main Building on central campus so there is a lot more than just the theater tied in. Some other odd thing is that there seems to be very little problem with the computerized house light system in the space. As far as I can tell we have never had problems with that but I suspect that if there is a power shift it is just low enough so that the computers are insulated against it, but the lighting system is not. I'll get pictures up as soon as I can. But about half of our lamps are "metalized" if you mean that the interior of the glass has a silver coating. However another quarter is pin burnouts like the one described above and the last quarter is broken filaments.

Thank you all. I don't know if This is kind of a crazy idea or not, but I've been eliminating variables as I go and continuously find my self right back where I've started. I hope this reply helps to explain what's going on a little bit better and I will try all of these suggestions.

 

[GreyWyvern]

...What's happening is the Pin on one side of the base of the lamp seems to be corroding; while the other is still in new condition. ...

Take a look at this thread.

http://www.controlbooth.com/forums/lighting/17741-bottoms-lamps-being-burnt-s4-5-50-a.html

I know it's not talking about the same fixtures, but is that what is happening?

 

[JD]

With regard to Hertz, almost impossible unless you are off a generator. This is the frequency of the ac power and would not be location dependent.

FEL 575? Typo? As far as I know, the FEL is still 1000 watts. If the fixture is not rated for this lamp, then you will damage the fixture.

The bases are a different story. If a lamp went bad by burning the base, the socket is now trashed and must be replaced. Any new lamps you put in would be damaged as well. I would say damaged sockets is your likely cause.

 

[Les]

And I will reiterate the cautionary statement that you should not put an arced/corroded lamp into a good socket, or use a good lamp in a arced/corroded socket. This will spread the 'disease'. It has been compared to the spread of VD in the past.

 

[Footer]

Both of us use FEL 575's in our stock and from what I can tell his stock is maintained about the same as mine. I've been secretly swapping out FEL's for GLA's over the years but the problem still arises. I've also metered out a lot of the "Problem" bases personally and they seem to be functioning well. There is very little charring in the bases, but sometimes the bases do not function.

If you were putting FEL's in your fixtures you might as well pop out every base cap and replace every one of them, along with your reflectors and shutters. That is a 1000w lamp, the fixture is designed to take a maximum of 600w. The GLA or the GLC is the proper lamp according to Strand, but if you were running FEL's at any time, the damage is done. As previously mentioned, there is no such thing as a 575w FEL. Any ANSI Coded lamp is made at a specific wattage and thats it.

Also, just because you both bought fixtures at the same time does not mean they will wear the same. Where the fixture is hung, how often its on, and how often its moved all matter when looking at fixture life.

 

[Dionysus]

...You are using FELs in your Strand SLs?

Specs for Osram Sylvania Lamps (yes I pulled them from me...old book):
ANSI - Volts - Watts - Base - Bulb - Filament - Avg Live - Colour - Lumens
EHD - 120 - 500 - G9.5 - T4 - CC-8 - 2000h - 3000K - 10000
FEL - 120 - 1000 - G9.5 - T6 - CC-8 - 300h - 3200K - 27000
FLK - 115 - 575 - G9.5 - T5 - CC-8 - 300h - 3200K
GLA - 115 - 575 - G9.5 - T6 - C-13D - ? - 3100K - 12360 (some taken from the lamps article)
GLC - 115 - 575 - G9.5 - T6 - C-13D - 1500 - 3200K - 15500

HPL 575/115v - 115v - 575w - 300h
HPL 575/115X - 115v - 575w - 2000h
HPL 575/120V - 120v - 575w - 300h

There's your problem right there!

If you are using a 1000w lamp in a SL (not rated for 1kw) you may be starting to overheat the base, causing your problems.

Properly stated it's not Hertz it's FREQUENCY (Hertz is the Unit), just like VOLTS is the unit for potential difference.
There is no way that any frequency or voltage problem from the service of the building is causing ANY of this, if it was that off you'd be blowing up every computer, fuse, and light in the facility.
Everything out there in electrical land is in Parallel, so the voltage and frequency is all the same. Only When things go drastically wrong you can run into these problems.


Ensure you are using the correct lamps for your fixtures.
Ensure the lamps are clean and seated properly in the fixture.
Ensure the fixture is in good working condition...

You want good contact, poor contact causes arcing which causes carbon (black stuff), welding, excess heat, etc.

I actually just had to replace a socket in a fixture, where a FEL had welded itself to it because a rookie did not seat it properly.

 

[ship]

A few lamp types left out amongst a few brands. The 750w/115v series for instance.

Primary question in trouble shooting not asked yet and might not be related but are you also runnig moving lights on this system? Voltage spikes as with power supply drops in higher can play a factor though normally in the lamp filament. Bases going before lamps assuming no swapping of used lamps between fixtures is often an overheating problem. Yep.. if FEL, that would do it as with a bad lot number and type of base.

FEL lamps... could be enough to trash bases. If not, perhaps a bad lot number assuming new fixtures with sockets.

After that, what sort of lamp hours are you getting on these lamps and what specific lamp are you using?

Also the factor stuff not expected like heating/cooling, proximity to the ceiling, perhaps encasing such a fixture in a small area etc. which woud overheat it.

Once put a FEL into a coffee can with small holes punched into it. Was attempting to create stars on stage. What I got was overheated failure. Cooling can be a factor also if not sufficient in an other than normal way. Filament of the FEL was too big to get good stars while the effect lasted.