Halogen lamps blowing rapidly?

When you say 'blown' I assume you mean the filament breaks and the glass tube is intact?

If the glass tube breaks then that is a sure sign that it was contaminated...

But if not I can't think of any reason for them to go after so short a time, unless they're constantly being switched on and off? or maybe there's some nasty spikes on your voltage supply?

Otherwise I haven't a clue!!

John.

Mabe try some sort of surge suppression?
Extension leads with surge supression (for PCs) are pretty common, maybe try running 'em on one of them. You havn't got someone with an arc welder or somesuch next door have you?

Bottom line is if the house supply is weird for some unfathomable reason youll just have to use an alternative type of bulb...I've heard all sorts of anecdotal stories (what other sort are there???) of houses with peculiar mains supplies. My Brother once had an electric meter which registered really low consumption...he had it checked beacause he didn't want to get hit with a big retrosective bill...they couldn't find anything wrong (but the bloke said he wished him meter was like it!)....so he just went over to electric heating!

Del

Would you have noticed on other equipment such as computers or laptops if the supply was "weird" or had big surges?

I have never noticed anything for the 10 years I have lived here and I am in a residential area without neighbours that have welders or transformers as far as I can tell.

A few had blown the end cap off and displayed some sort of "growth" on the end where it had burned. I am sure that one was dirty. Some others just burned the fillament and as such just powdered the glass black or silver on the inside.

The one that is in there now has worked for over 15 hours so far so perhaps you should always clean them even if you don't touch them your self.

Strange.

Owwww just a thought case491, you have fitted them in a ventilated fitting haven't you?

Those 500 watt bulbs do need a lot of ventilation to stop them overheating... I have a photographic halogen lamp and it is rated at 1kW but only for 5 minutes before it starts to overheat...

I wonder if that could be the problem?

John.

i agree with you Halogen lamps generate hell a lot of heat and commit Harakei this is my experience working in 5star hotels (we were replacing Bucket loads of lamps assorted wattages every week)as a chief engineer for more 20years its not just the replacement cost of these lamps one has to think of driving heat load calculations in to the drain and creating another problem of up setting room temperatures & cost of energy cost of Airconditioning ,but as engineers we are helpless as halogen lamps are first choice of Architects and decorates. if some one prefers and values the looks the price has to be paid in spite of shouting green and energy efficient buildings as long as appearance takes importance engineers will be blamed for high cost of operations and maintenance costs.

crm

Hi Case 491,

A loose neutral connection could be a cause. Also ensure that the light switch is breaking the hot wire and not neutral.

A broken neutral anywhere in the circuit could induce high voltages... a
neutral wire disconnected at the breaker box will change a pair of 110
volt circuits into a single 220 volt circuit with appliances from one
circuit electrically in series with appliances from the other.,

Other reasons could be surges from utility supply, improper heat dissipation causing overheat,vibration causing loose connections at the fixture.

1. What is the orientation of the lamps? Linear halogens must be mounted horizontally.

2. You say voltage is OK but how can you be sure? Only a continuously connected meter with recording facilities will measure the voltage all the time. Digital meters sample the waveform and cannot respond to momentary spikes in the supply.

3. Are you measuring the voltage at the lamp or in the switchboard? You could be getting excessive volt drop in the supply cable to the fittings.

Two things - overheating and voltage spikes.

Make sure that there is sufficient air flow to prevent overheating. If your problem then continues, get a recording voltmeter (oscilloscope?) and measure the voltage until you get another blown bulb. You would then have a reference to work against. You could try surge protection in the circuit.

Question for one and all...is under-voltage as bad as over-voltage for halogens?

(PS They last longer is you don't turn 'em on )

Del

Hey Del,

I would think that undervoltage would not be as damaging, but I am not and expert.

I base this answer on a recently purchased ceiling fan I own. It has a halogen lamp in it but it is dimmable.(is that a word?) Any how it on a dimmer switch and works great at both low and high output.

I agree with the comments on heat and positioning of the bulb. Because of the type of light halogen produces the heat from it is readily absorbed into any fixture. If the fixture does not have some slits in it or a heat sink on it this could be the problem.

As other posters have mentioned, overheating is most probably the cause......many fittings are either badly designed or badly installed or both.

May I suggest some modern CFLs (230 volts) or LEDs (12 volts) which in the main run much much cooler and will last much much longer.

Just remember to buy single lamps first and let your wife decide which color (warm white or cold white) she prefers......

....or add some cooling to the fittings in some manner.....air blown into the false ceiling can help for instance, with several small silent fans. But that costs even more electricity, but will make that warm air available to warm up the room in winter!!

Must be Chinese make. Buy better and reputed makes.

Has anyone checked the lamp Sockets?

High resistance of contacts will also cause lamp to overheat and burn... even if everything else is correct!

Hear build up is not the problem. I have installed these types of halogen lamps inside of industrial ovens for years. These fixtures were sujected to vibration and high temperatures, and they usually lasted several months of continuous use. The lamps did have the tendancy to burn out when we were switching our power from one generator to the other(primary power to back-up). You are either experiencing "spikes" or as mentioned in previous response, an over-voltage situation.

GOOD LUCK.

Ok to try and answer all above suggestions in one (I hope).

No vibration.

Fitting is horizontal with no more than 15degrees tilt.

Fitting is designed for these filaments up to 500 W without cooling. It has worked in my workshop for months on end no problem. Problem started when I moved it and installed new bulb without first cleaning it thinking it was good to go from the pack.

Several brands which could all be made in China for all we know but one was Osram which is regarded as very good.

Voltage is ok and no other equipment is suffering spikes so I have to assume it is ok.

Fitting contacts have been cleaned.

The lamp which is in there is now going for over 25 hours so I think it has to do with deposits on the glass when you get it out of the pack.

My advice to all is to always clean the bulbs down before using them, I really think that that is all that there is to it.

Many thanks for all your replies.

May be the move. For some reason may not be cooling properly.

Sounds like you have it under control, but it's the voltage to the bulb, not the fixture that you have to worry about along with heat and surface debris. Bad switches dimmers and the like can cause problems.

I really liked the "fans in the ceiling" idea, but have you ever considered installing dedicated low temperature water cooled refrigeration equipment? It could be months before you have to buy another bulb.

Sorry to maybe "rain on your parade", but if the glass did not actually break, then it was not a glass cleaning problem. Dirty glass causes uneven heating and breakage.

If the lamp simply burnt out (filament gone), either it was cheap crap or it got too hot or both.....

Yes, I agree Andy...

John

Are the replacement lamps low quality counterfeit?

Hi. I had a similar problem. Installed 500W lights (2x) and they worked for months. Then one light went dead. After that it just kept on blowing every so often. Could not get it right. Soon both units acted up. Then put 300W globes in same 500W units. Worked a bit longer but still blowing. My mate in the electrical shop then brought me some 150W globes incl some spare globes (just in case). Must say, I installed the 150W, and it has been working ever since. I have since moved houses and installed the same 2 units at the new house. Been living here 3 years now and the lights still working. Still have the spare units. Must say, looking back. Only the original globes the unit came with lasted.

Quote from Mr Mannering "Stupid Boy!"

YOU STUPID BOY !!!

Two main causes of premature death on quartz lamps (heat is NOT one of them, they use these things in OVENS for crying out loud):

1. Voltage spikes: Although not common, these can come from a lot of sources in a home. For instance, if the bike shed has an air compressor, every time that compressor turns on and off, it will create a spike in the line. Any kind of large machine can cause it, maybe even a shop vacuum. It could be that in the old location, there was enough wire impedance between the source of the spikes and the lamp. Now that you moved it, there is less impedance and the effect is greater.
2. Cold-to-Hot transitions: The filaments in quartz lamps have what is called a Positive Temperature Coefficient (PTC) of resistance, meaning the resistance goes up as the temperature goes up. That also means that when cold, the resistance is low and if REALLY cold, even lower. So when you turn it on in a cold environment, it has very low resistance and the current "rushes in" just like a short circuit, until the lamp heats up and resistance increases. When this happens, the glass can sometimes crack and/or the filament is stressed. A way to avoid that is to use a dimmer switch to turn it on and off, because it naturally applies a "ramped" voltage to the lamp by virtue of how long it takes you to turn it all the way up. Even a fraction of a second is enough. The lamp manufacturers don't tell you this because they want to sell more lamps !
   
   There is a reason why people perceive that the original lamps last longer than the replacements by the way. What some manufacturers do is to install an NTC thermistor in series with the hot lead in the fixture, which has HIGHER resistance when cold and lowers as it heats up, so it acts as a "soft start" to the lamps. But over time they burn out and short, leaving you with nothing. You may not even be able to see the NTC resistor anywhere unless you know what to look for, it can be a small device clipped into the lampholder or even something that looks like a piece of wire. You may even had not noticed that you tossed it away when you un-wired the fixture prior to moving it. They are not easily attainable for replacement, but using a dimmer accomplishes the same thing. I use a dimmer that looks and acts like a regular toggle switch, that way I flip it on just like normal. My lamps last for years.
   

Afraid I have to disagree JRaef,

When I stated overtemperature I wasn't meaning being a bit hot, such as an oven... I meant hot is in melting glass temperatures... in a focussed reflector type of fitting the 500 watts of heat produced when focussed back on to the glass bulb can easily melt the tube, or at least result in premature failure due to excess heat in the filament.

If you doubt it just buy a photographic halogen floodlight such as mine its rated at 1 kW but only for 5 mins... for 500 watt its 15 mins 250 watt it can last a good 25 mins. The fitting is fully ventilated but the tube still will overheat if left on...

John.

OK, I'll concede that point. He could have a fixture meant for short term operation and he is using it continuously. Or I suppose someone could design a fixture inappropriately for the task and have it overheat the lamp. I guess I'm guilty of ASSuming that a fixture manufacturer knows what they are doing when designing it, but nowadays, that is maybe not a good assumption. So I retract my "NEVER" part of that statement.

But...

He said that it worked in another location for months with no problem, then the problem started after he moved it, and continued even after he lowered the wattage to 300 from 500.

There might have been some important difference that changed the cooling in some manner....

Case has not stated (as far as I am aware) as to if the glass envelope is broken or cracked with white residue, or black residue or filament melted or crystalized....that could help us further.

Even though OP reached a conclusion, we always used to wipe new lamps with alcohol before installing them.

We could always tell when someone didn't because their fingerprints were etched into the swollen quartz envelopes.

And BTW we used to get 15 min at the 1kW brightness by dimming the filaments to bright orange and never allowing them to get cold.

The color of the deposit on the inside can tell you about the mode of failure too. Lately, the manufacturers aren't putting enough Iodine in the tubes, and the result is the dark deposits on the quartz. If you see white chalky deposits, then oxygen/air got in.

The happiest mode of failure is when the filament looks like tiny, bright, needle-like crystals, that just finally broke. Maybe a little melted near the break. If you get that you got everything the lamp had to offer; smile it was a good life.