"Jeff Wisnia" wrote
Does a dimmer constitute a soft starter? IOW, does it block current until voltage zero-crossing? Obviously, you are not turning the lights on at the dimmer. It is in series with your regular switch.
Strange comments, coming from the dimmest bulb in the universe.
This is Turtle.
Let me give you some electric data and then you will tell me what your problem is.
All light bulbs now days are rated to be used with 120 volt electric service. Most all electric service voltage supplied to homes now a days runs between 120 volts to 125 volts. So you are running a light bulb rated to run on 120 volts and suppling 124 volts service to it and I call this over powering the rated 120 volt light bulb with 124 volt electric service .
Now tell me why the bulbs are burning out so fast.
Now here is a little hint here. Just get light bulbs rated for 130 volts and light bulbs will go back to running a year and not days. Now there is another word for this 130 volt rated light bulb and it is called Ruff Service light bulbs. You can find some brands of light bulbs that are rated for 130 volts but you will pay 3 times as much for them because they are well made and don't burn out so fast. All light bulbs have the rating stamped on the top of the bulb for you to see.
TURTLE
This is Turtle.
OOOOOO I must have step on your Troll Blanket sometime. Sorry about that !
TURTLE
No. OP noted that his lights die only at the moment that the light switch is turned on. This has zero correlation to the line garbage that you are talking about.
"Evon" wrote
I don't thing the long life I'm getting is from a "soft start", which to my understanding is a slow increase in voltage/current which takes maybe a second or so and never lets the current get to the high levels it will reach when a cold bulb filament is suddenly connected to full power. I suspect the thermal lag in a good sized bulb's filament may be enough so that not much is gained just by having the first half cycle of power to the bulb start at a zero crossing, though that can't hurt either, can it?
I'd rather go with the theory that running the bulbs a bit down from their rated power is akin to using 130 volt bulbs, and the evaporation rate of the filament is down by whatever exponential ratio fits the reduced power, and thus they "last longer".
And yes, I do have the original wall toggle switch ahead the dimmer.
Don Klipstein should check in here about now, he's my acknowledged light bulb guru. There's more than you probably ever wanted to know at his great site:
Jeff
resistance of a
elements. So
Your recollection may be inaccurate. Triac light dimmers actually work by assuring AGAINST zero crossing startup. Except when full-on or off, the dimmer operates by delaying the current with respect to the voltage zero crossing, 120 times per second. When at 50% duty cycle (about 1/2 power), the current starts 1/4 cycle behind the voltage, i.e. at the PEAK of the voltage sinewave, and stops when the voltage passes through zero, so only the last half of each positive and negative half-cycle is used.
Some heater controls modulate power by energizing the element for a certain number of full cycles, deenergizing for some number of full cycles, and so on. Here, zero crossing can be employed. This scheme is not so good for lighting because the "blink rate" is well below 60 Hz and would be quite noticable.
The question to be answered is how much of a difference does it make using the last half of the sine "bump" vs. the first half, in terms of energy imparted to the filament per cycle, taking into account the mass and heat capacity of the filament, etc. etc.
I suspect that during rapid warmup, one segment of the filament gets hotter than the rest, which makes its resistance go up higher, which means it receives more power than than its neighboring segments which still have lower resistance. Since it receives more power, it heats up even faster and resistance increases even more. The hotter segment also expands more rapidly and suffers greater mechanical stress and fatigue as a result, becoming a likely point of failure.
Bringing the current up slowly, over the course of a second or so, allows time for all segments to heat at closer to the same rate, as well as time for heat to diffuse from one segment to another, allowing more uniform heating and greatly reducing the chance of a local hotspot forming.
Some of these ideas can be demonstrated by experimenting with bulbs in series, which is effectively a single filament divided into segments. Say you have a car battery (12V) and 5 to 10 identical automotive bulbs in series. When you complete the circuit, you'll see that one gets initially brighter than the others, then it may even get dimmer as the others "catch up" to finally achieve uniform brightness. That's because even though they are "identical," there are slight differences in the bulbs and the one with the highest initial resistance and/or the quickest heating filament will absorb most of the power till the others heat up. I noticed this effect when I was about 6 years old, though I had no idea what was causing it; I just knew I could rearrange the order of the bulbs in series till they lit up from left to right and it was pretty cool.
%mod%
installed.
I like the CE, Sylvania and some other brands CF lights for certain applications. They are "instant on" and can even start at 0 degrees Fahrenheit, even though as you note they have a warmup time. One other thing worth noting is that some fixtures have a limit of 60W per bulb, incandescent. You can substitute 23W or 28W CF bulbs and achieve better illumination.
CF bulbs are not as good where you'll turn them off before they'll achieve full brightness, meaning they're most effective where they'll be on for minutes to hours at a time.
I like dimmable halogens for reading lights.
%mod%
I've never noticed that effect, but it seems possible.
I'm guessing it was holiday lighting (Xmas tree strings) you were experimenting with when you were around age 6, right?
I'm having a hard time visualizing what ten 12 volt bulbs across a 12 volt battery would end up doing. Wouldn't seem like there'd be enough voltage available to produce anything other than infrared "uniform brightness" with just 1.2 volts across each bulb, or did you misspeak about the battery's voltage?
Oh, and my face is red for geting lured into agreeing that triacs "switch on" at zero crossings. I know better, but it's been so long since I built anything with triacs that I forgot that they "latch on" once triggered and have to wait for a current zero crossing to drop out.
Jeff
Impressive commentary! Thank you for clarifying the triac methodology. That was quite the observation for a 6 year old. I trust that was quite a while ago...!! So that speaks well of your memory, too. Seems you were a "natural." I have an attractive light fixture, which has been dark for years. The fancy bulbs required for it burned out within days of installation...ridiculous. Got tired of feeding cash into this fruitless effort. There are four bulb sockets. The fixture is controlled by two
3-way switches; it's at the base of stairs.This thread has renewed my interest in reactivating the fixture. I will put a standard (non 3-way) slide-dimmer at each of the two switch locations. SLIDE is critical, to force the user to warm the bulb filaments gradually. The catch is that TWO DIMMERS cannot cohabitate in the same 3-way circuit; because it seems highly imprudent to put two dimmers in series. Your rebuttal would be welcome. So... I'll should split the fixture sockets. Two sockets will be controlled by one slide switch; the other two sockets by the other switch. This way, at least there will be some light, if only one switch is slid to its "on" position. I have another stairwell, which has two 3-way switches. One is a push-button dimmer; of a 3-way nature. The other is a conventional 3-way lever switch. The bulbs controlled there *never* burn out. I hesitate to use this proven configuration with the fixture whose bulbs die so quickly. I want those delicate bulbs to *always* light up slowly.
wrote
Hi, I told you already, take a look at thermistor or diode "bulb savers" they'll give you a soft start or the effect of reduced voltage you need. They are available to suit both standard and candelabra base sizes
Here's some:
Or, you could try the solution which I described as working for me in our bathroom. use a conventional multi location toggle switch control system and add a lamp dimmer just ahead of the bulbs, located out of easy reach, and set it to "90%" or so.
You are correct about there being no easy way to just use two off the shelf slide dimmers to accomplish a soft start from either of two locations without adding a LOT of complicated electronics.
HTH,
Jeff
segments.
I did some of that with Xmas lites, yes, but my parents indulged me with electrical stuff from the hardware store as well. I had a bunch or light sockets, battery holders, switches, wires etc. that I could play with, even some "house current" stuff. I only blew the fuses a few times. I also dumpster dived a lot, for example I'd scrounge phonograph turntables as flywheels for DC motor/generator systems, which taught me something about regenerative braking.
The bulbs are a dull red-to-orange at 1/10th to 1/5th voltage, and it takes one-to-several seconds to warm up to final brightness, but they generally do light. I said "5 to 10 bulbs" because it depends somewhat on the particular traits of the bulbs. By adding more in series, each runs at a lower voltage and takes longer to come to final brightness, such that your eye has enough time to follow the changing luminosity, up to the point where there are too many to see them light at all.
Yeah, well, the memory is the second thing to go, and I can't remember what the first one is.
%mod%
Yeah, me too. Never forget the time I had my mom by me a plug fuse, with me thinking it was a different kind of light bulb.
Screwed it into the lamp; turned the switch... and;
well, you know the rest.
Fuses actually do make great light bulbs; they just don't last very long.
methodology.
you were
Thanks for the complement. I was a natural at some things but a failure at others.
locations.
gradually.
I like the Lutron sliders for the reason you describe.
Technically I think dimmers in series should work, but of course if you turn any one off, the other(s) cannot turn the system back on. With dimmers in parallel (with each other), all would have to be turned off to make the light go out. So I agree it's imprudent.
I have Lutron 3-way sliders which push on and off. Each slider teams up with a normal 3-way at the other side of the room. When I turn the lights off at the slider by pushing it, I place the slider in the 60% position so that when I turn it on at the other switch, I don't get blinded by the bright light. It has also anecdotally lengthened the life of the bulbs, several years since a replacement.
controlled by
Another option is to use X10 or remote-multiway type dimmers. The ones I like best are the Smarthome ToggleLinc line, because they use regular switchplates. I've used their Togglelinc PLC (X10) switches to control compact fluorescents. Anyway, if you don't want/need to have X10 compatibility, then by using the same wires as a "regular" 3-way configuration, you can use the "hardwired only" Deluxe Dimmer 23897 with the multiway companion 23892
%mod%
"Jeff Wisnia" wrote
Thanks! I inquired with a couple of lighting and electrical shops, and they hadn't heard of these.
Those are apparently the "diode" version of bulb saver, not the thermistor. According to Don Klipstein's webpage (somebody already mentioned that link, here it is again,
The only non-diode, drop-in soft starters I could find were Bulb Boss and Longlite
%mod%
You spoke the truth and tought me something I didn't know.
I wouldn't have believed that there'd be any light in the visible spectrum at 1/10 voltage, but I just played around with a few small "12 volt" automotive bulbs and my bench supply and they all put out a red glow visible in dim light right down to 1 volt; and some even below.
I found one bulb which at 0.7 volts produced a little dull red in the middle of the filament (The furthest point from where the filament supports were sinking the heat away.)
Jeff
I suppose it's because as the filament is cooler running at reduced voltage, the resistance drops, so the current falls off more gradually than voltage, and the power and filament temperature are decidedly nonlinear functions of voltage.
%mod%
You're right, you're no electrician.
And what wattage do you recommend?
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