Lamp life too short!

[iwire]

Re: Lamp life too short!

Originally posted by oldmanriver:
2. Iwire - The reason arching causes the shortening of the lamp life is two fold, first the current rush into the filament is the primary thing that causes bulb burn-out,

Understood but seeing as this is an AC circuit you have the voltage going to zero all the time anyway.

If your saying the connection is so bad that the filament is actually cooling down significantly this would be noticeable to the eye and would suggest a loose connection.

Originally posted by oldmanriver:
then you will understand why the voltage in an arching circuit will easily jump to over 240 volts and blow the lamp.

I would like to see some figures that show the inductance in a typical lighting ciruits will cause peaks of 240 volts to the filament remembering the peak to peak voltage is already about 180 volts.

Would this not be a problem when opening the light switch too?

Originally posted by oldmanriver:
I suggest going back taking off the wire nuts, twisting the wires, well, soldering them, then re-install the wire nut.

I suggest you do not do that unless you can find some wire nuts that say solder first. ) Wire nuts when used as instructed do not fail nearly as frequently as you make it sound.

There would be a lot of dark buildings if wire nuts failed as much as that.

Just my opinion formed from installing tens of thousands of wire nuts.

Bob

 

[Ed MacLaren]

Re: Lamp life too short!

Noticed another "inaccuracy" in oldmanriver's latest post.

if you understand the physics of current vs. capacitance (the principle used in florescent lamps to boost the voltage to over 2KV

Ballasts use the transformer principle to boost system voltage for lamp starting. Magnetic ballasts are actually an auto-transformer, and electronic ballasts are a type of switch-mode power supply with high frequency output.

Typical lamp voltages would be less than 400 volts for 4 ft. lamps, and less than 800 volts for 8 ft. lamps.

Ed

 

[oldmanriver]

Re: Lamp life too short!

Ok so I have a lot to answer so here it is:

Peter D:
I don't have the calculations, because I got rid of my Physics book years ago. It's been over 20 years now, but if you want the answer either contact any physics professor at your local college, or if no local college with a physics department exists, contact one on-line. They will help you out.

Steve:
Yes you are right about the highest voltages occurring across the point of arc but remember the filament is helical, meaning inductance, therefore there will be increased voltage on the filament. Also remember the inductance load goes up as the frequency increases, so a smaller arch, produces higher frequencies and therefore higher voltage on the filament. I choose 240 volts as a nominal, because if you understand this principle and arching is right the voltage could easily exceed 2KV at the filament.

I design and repair switching power supplies, variable speed motor controls, etc. and snubber networks are put across the transformer secondary or motor just to deal with this phenomenon.

Iwire:
Actually AC is the culprit and the filament is wound to deal with the 60Hz but not with higher frequency. Frequency is the problem here and yes arching from a switch can have the same effect, but is minimized by the short duration. If you however have continual arching while the lamp is on, different story. On the solder, if you have them, knuckles will do fine instead of wire nuts.

Ed:
I'm sorry but I've never met, in the over 1 million ballasts I've replaced, an auto transformer ballast. All the one's I've worked on were series induction type with calculated resonant frequency of 60Hz for bulb type. If you were right the bulb type would not matter any ballast would fire any bulb, but since I'm right wrong bulb won't work on your ballast because capacitance of the bulb is critical in reaching the voltage needed for proper florescent operation. Again this is a question you can consult your local college physic professor on, he be glad to set you straight.

True to new electronic switching type do their own voltage multiplication and therefore don't even need the filaments in the end of the bulbs and if they have enough ampacity will light any bulb because they are not part of a series inductance capacitance resonant circuit.

 

[scott thompson]

Re: Lamp life too short!

I really did not want to get into this potential flame war, but I have just read some things which really do not make a lot of sense!
:roll:

Again this is a question you can consult your local college physic professor on, he be glad to set you straight.

Can't believe you said this to - of all people here - ED!!!

True to new electronic switching type do their own voltage multiplication and therefore don't even need the filaments in the end of the bulbs and if they have enough ampacity will light any bulb because they are not part of a series inductance capacitance resonant circuit.

That's the sillyest thing I have read all Month!
Just what do you think the level of Voltage (Potential Difference) would be across a Fluorescent Lamp during normal operation?
Please don't say thousands of volts, even hundreds of volts!

hint: high Impedance = high voltages, low Impedance = low voltages...

I am sorry to throw these flames out, and appologize to everyone in the forum, to "oldmanriver" for my coarse 'Tude, and especially to Ed! I just had to say something, because the Poop was getting too thick!

Time to go back to my cage...

Flames may begin now!

Scott

 

[iwire]

Re: Lamp life too short!

Originally posted by oldmanriver:
in the over 1 million ballasts I've replaced,

Wow you are old! about 400 years.

Your new here, so you do not know Ed or Scott, but if you want to be taken seriously you may want to do a member search and learn about these two gentlemen.

Give me all the grief you want, I am just an average Joe electrician, many of the other members are much more than that.

Bob

[ March 11, 2004, 04:52 AM: Message edited by: iwire ]

 

[oldmanriver]

Re: Lamp life too short!

I guess I could get insulted by all the flack and I did not mean to hand out any, so sorry if I offended any. I guess I got a little testy after getting zapped on my "Wire Nut Arching" suggestion.

Guys I would not have submitted it, if I had not by experience found that it is a problem. Sorry you took it the wrong way.

When I was talking to Ed about "not Auto-Xfmr" I think, at least I hope, he understood what I'm talking about. Design is different and wound different, but I understand his point because some characteristics are the same.

When you design and wind, you learn a lot more than just pulling wire and "nutting" it together, so no offense meant to anyone, I was not meaning to get crusty, just trying to explain some principles and theory behind why things work, since I know, from experience, it may be part of the Light/Lamp failure.

We are suppose to be helping with here, not getting into contests about who knows what, so I apologize for contributing to it.

 

[roger]

Re: Lamp life too short!

Oldmanriver,

Design is different and wound different,

do tell, how so?

In any case if a ballast (even if a million of them) is wired in an Auto Transformer configuration, it is an Auto Transformer period.

Roger

 

[james wuebker]

Re: Lamp life too short!

Alot of good ideas. Put a Fluke 87 on line and check voltage in this circuit. The meter, you can keep on for a day and it will tell you your low,high and average reading. See if your volage is changing. You might even want to check your main box. See if you can find the voltage raising in the circuit. Let me know if you find something.
Jim

 

[stanley]

Re: Lamp life too short!

Hey guys sometimes we over analyze. In the last few years we have found that customers when buying replacement lamps or bulbs buy the cheapest thing on the rack. China, Taiwan, Korea, India, you name it. We recommend using brand name lamps & bulbs and more often than not the short lamp life problem goes away.

 

[benaround]

Re: Lamp life too short!

Rich, too bad you can't ask a simple question without whatever all that was !! Do you live on a street that heavy trucks use all the time , are there railroad tracks near your home ,do people slam your front door closed a little to hard ? These are some of the things I have found over my 37 years that will make lamp life real short. p.s. I have also seen lights burn for a real long time with no wirenuts at all,just the wires twisted together.

 

[scott thompson]

Re: Lamp life too short!

Oh, this thread is alive again!

Got a big question: Has any of this helped the original poster, and what's up with the failure rate of the Lamps?
My most primary question would be if El Cheep-O type Lamps were used.

Still curious to see whazzup!

Oldmanriver:

I guess I could get insulted by all the flack and I did not mean to hand out any, so sorry if I offended any. I guess I got a little testy after getting zapped on my "Wire Nut Arching" suggestion.

Guys I would not have submitted it, if I had not by experience found that it is a problem. Sorry you took it the wrong way.

No problem. We tend to push for the truth rather hard, making Fox Mulder's search for the truth look like a walk in the Park!

I had issues with certain things - as you most likely have seen!
Which brings up a few more points to discuss:

When I was talking to Ed about "not Auto-Xfmr" I think, at least I hope, he understood what I'm talking about. Design is different and wound different, but I understand his point because some characteristics are the same.

Could you elaborate a bit more, on which Ballasting elements you have dealt with in the past, are different than the common type Auto Transformer / Reactor types. I am not being a Jerk - I really want to discuss this, and see what's up.
All the Ballasts I have dealt with (Discrete Components / Core-Coil, Encapsulated - all Linear "Magnetic types) either employ a "Straight-Out" Autoxfmr, have connections which result in an Autoxfmr, or if input situations are sufficient - are simply a Linear Reactor without any Xformer.
Some HID setups use an Isolated Transformer with two Secondary Windings, but these make up a small number of the common use setups.

When you design and wind, you learn a lot more than just pulling wire and "nutting" it together, so no offense meant to anyone, I was not meaning to get crusty, just trying to explain some principles and theory behind why things work, since I know, from experience, it may be part of the Light/Lamp failure.

I have only wound a few Ballasts - only for experimental "Smoke Tests" and because "it was fun" (read "Geeky"!), but have wound many Inductors ("Chokes") for Audio system crossover networks.
The prices of these Animals off the shelf, along with the standard values - in mH, makes it reasonable for me to wind my own!

Have wound a few small Isolation Transformers for fun too! Also wound some CTs

We are suppose to be helping with here, not getting into contests about who knows what, so I apologize for contributing to it.

Best statements ever!
I also am sorry for tossing Gasoline on the flames!

On last thing... please refer to Electric Lamps as "Lamps" - not "Bulbs"!...
Just a little humor...

Scott

 

[richwaskowitz]

Re: Lamp life too short!

Wholly schmokies!!!

I've only posted a few questions to this site, the first one is still going at 142 response, and this one at 50. I'm going to get a rep as a trouble maker.

Thanks for all the answers and suggestions. Really. There is no abnormal vibration, heat or loose connection problem. The lamps were either Sylvania or GE off teh shelf at the local supply house, not the ones from the far east or something.

I have come to the conclusion that those old drop-in discs went by the wayside and I don't feel like messing around with a silicon diode installed at the timer, so and I am going to try the compact fluorescents. The 14 watt / 60 watt jobs look like they should do the trick and the manufacturer claims 7 years of service. If I get 1 year I'll be happy.

 

[mthead]

Re: Lamp life too short!

Dealt with this problem in many high end installations. 20' high cielings with 60 recessed cans over a Italin pink marble floor were the rule -not the exception -[thank God for the "alladin lite lift" for the chandeliers installed the middle of these electricians adventures]--so the hope was that you'd avoid having to go back to replace a bulb in these palaces for as long as possible-our best results came by installing "extended-life, hard usage bulbs" in these hard to get at locations .They were avail .by special order at supply house and came with avg. use rating of 2500 hrs. or more depending on what you were willing to pay.They were used only in the difficult access areas ,were also not left at site during reg construction so people could just usethem anywhere-and h/owners were willing to pay extra rather than pay 65.00 per visit down the road just to change a bulb.They were getting 2 yrs easy in our experience using them.

 

[steve66]

Re: Lamp life too short!

Rich:

You're a troublemaker!!

But really, from my personal experience (no hard facts to back this up) Sylvania bulbs are a world above the other brand you mentioned.

Just to be sure you know, one thing about the compact fluorescent (I assume you mean the kind that screw into a regular fixture) is that they don't get to full brightness until they warm up for about 30sec to 1 minute.

 

[tom baker]

Re: Lamp life too short!

Regarding lamps (bulbs grow in the ground)
There is a difference between lamps. I am on call for traffic signal problems, including lamps burnt out. Its a very expensive call at 2 am for two persons, and a truck! We found a long time ago that Sylvania had the best reliability. Our state DOT was able to track and document problems with one manufacturer of lamps, over a period of years they showed this particular mfg had more problems with lamps going bad.
Our ultimate solution was to go with LED displays. This has saved thousands on power and callouts.

 

[richwaskowitz]

Re: Lamp life too short!

Mr. Baker. If Bulbs grow in the ground, then where do "bubs" come from? I had a customer ask me one if I kept "ode light bubs" in my truck. She wanted to put them into unused sockets in her ceiling lights so that the "lectricity don't leak out the hoes". I kid you not.

 

[stanley]

Re: Lamp life too short!

Ok I can't resist, just on more post on this wide ranging subject.

It has always been my experience that A type incandescents were called bulbs. (Maybe because they look like those things that grow in the ground.). Everything else is called a lamp.

 

[mthead]

Re: Lamp life too short!

You can call them lamps ,A-types,R-40's,par-38's--Out in the field here the contractors ,mechanics ,and supply house rep's tend to call them bulbs as often as not.Sorry ,I guess it must be a NY thing.