Chandelier with 3 wires????

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Old 05-27-14, 03:03 AM
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Chandelier with 3 wires????

Hello, i am having a mysterious problem with a chandelier that I recently acquired.
It is an Italian design from the 1960's and has eight light bulbs and three wires. None of these wires are structural since the lamp hangs from a robust hook which is screwed onto the lamp shaft. The Mystery; I tried just two of the wires and all 8 bulbs light up but extremely dim. Then I switched one wire with the unused one and only 4 bulbs light up with the correct brightness. Then I combined those two together so that all three are wired and only the 4 bulbs lit up again at the correct brightness. Then I switched one of those two with the other wire that I hadn't changed yet and the other 4 bulbs light up at correct brightness. Then I removed one of the two wires that were together and all 8 light up but again very dim, less than half the power. What is going on? Is there a resistor in there that is reducing the voltage or have i just not wired it correctly? Mathematically there is still one more combination to try, and obviously there is always the option of opening it up and measuring etc., but I wanted two ask if anyone has had any experience with such a circuit. My only conclusion is that it is wired purposely to operate this way, and that a special wall switch was necessary since there is no switch on the lamp itself. Any ideas?
Thanks
Lucas
 
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Old 05-27-14, 03:37 AM
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Welcome to the forums! Since it is from Italy, there is a possibility it operates on European voltage, which is 220 volts at 50Hz. Posting a picture of the fixture including as much of the wiring as you can may help glean better answers.
 
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Old 05-27-14, 05:01 AM
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Thanks for your reply, but I am in Europe actually, and the bulbs are normal 40w e14 (small fixture) rated for 220v which is what is coming out of the wall. I figured out that there are actually 12 permutations for combining the wires but 6 of them should be redundant since it just reverses the polarity. I decided to start by just testing the first 6 combinations with two wires by leaving one wire from the lamp always out. From the ceiling I have one Blue and one Brown wire ( there is also a ground wire which I attached to a given point on the lamp shaft). On the lamp there is a Brown, a dark Green and a Yellow wire. He's are the results (from ceiling to lamp);
Blue to Yellow / Brown to Brown = 4 bulbs bright
Blue to Brown / Brown to yellow = 4 bulbs bright (reversed polarity)
Blue to Yellow / Brown to Green = other 4 bulbs bright
Blue to Green / Brown to Yellow = other 4 bulbs bright (reversed polarity)
Blue to Green / Brown to Brown = all 8 bulbs dim
Blue to Brown / Brown to Green = all 8 bulbs dim (reversed polarity)
Another test I did was in the 8 bulb dim mode, I unscrewed one of the bulbs and 4 got brighter where as the other three got dimmer.
What stumps me is that there is no combination that breaks the circuit. So how is this thing wired? And there must be some passive elements in there, (thermal resistor), right?
Thanks,
L.
 
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Old 05-27-14, 05:15 AM
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Yeah, it always helps to have your profile filled out correctly. For uS voltage, it tells me the bulb sockets are wired in series. But, I know little about European voltages, so I'll have to defer to one of the others who will know more. Hang in there, as it is still,early.
 
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Old 05-27-14, 05:29 AM
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Thanks, I willi try to correct my profile but when I registered I did not have that option and was forced to choose a state, so I picked my old home state. Voltage is voltage so there should be no difference in how something is wired between the US and Europe except the gauge of wire maybe, and if they were wired in series then by removing one bulb, as I did, all others should go out as well since they wouldn't get any current, which is not the case, or am I mistaken?
Look forward to solving this mystery!
L.
 
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Old 05-27-14, 10:36 AM
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Okay, since I have not gotten any answers, I have come up with a theory based on the tests I did (see earlier post). My theory is that the yellow wire is connected in series to every bulb, but alternates between tip and screw socket. The brown wire only goes to the 4 bulbs where the yellow is connected to tip, and the green wire is connected to the tips of the other 4 bulbs where the yellow is connected to the screw socket. When Brown and Blue from the ceiling connect to Brown and Green on the lamp all the lights work but dimmer than normal because the current has to flow through two bulbs (via the yellow wire) before the circuit is closed. If one bulb is unscrewed then the 4 become more current where as the other three become less. I guess the only way to prove this though is to take it down and measure.
If true this poses some interesting questions.
1. Why?
2. What switch options are possible?
3. Is it possible to get all 8 lit at normal brightness?
4. What happens when I use different wattages for each bulb?
Wow, this could be a perfect school book problem for electronic circuits 101!
There must be someone out there that has had a similar experience? Or knows enough about light circuits to be able explain this circuit?
Anybody?
 
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Old 05-27-14, 11:00 AM
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I left you a diagram for the way it appears your light is wired. The colors are just ones that I picked for illustration purposes.

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Connecting power to blue and gray will make those four light normally.
Connecting power to pink and gray will make those four light normally.
Connecting power to pink and blue will make all eight light dimly.

You need to join the pink and blue wire for the hot.
 

Last edited by PJmax; 05-27-14 at 11:57 AM. Reason: redrew diagram for clarification purposes
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Old 05-27-14, 11:47 AM
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He said they still work when one is unscrewed, so they are definitely NOT wired in series.

You have to take it down and open up the sockets to see how it's wired. Guessing and making assumptions is a good way to get yourself killed.
 
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Old 05-27-14, 11:58 AM
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I redrew my diagram. I knew they weren't in series, I just didn't think I needed to draw the neutral all the way thru.
 
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Old 05-28-14, 02:22 AM
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Thanks so much for your help and drawings. It is like you say and as I surmised. The yellow cable runs to all bulbs. The brown to four and the green to the other four. By connecting brown and green together, those to hot, and the yellow to neutral, all 8 bulbs light up at normal brilliance!
Now I am considering putting an extra cable in the wall and buying a special switch so that I can choose between 4 bulbs or 8 bulbs by switching the wall switch. The 8 dim candle light effect was kind of nice too for that romantic James Bond effect, but I am not sure if that is bad for the wiring or bulbs.
Thanks again for all your help.
L.
 
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Old 05-28-14, 09:00 AM
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It may be easier to just use a dimmer instead of replacing the wire and adding a second switch.
 
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