Stray voltage and Energy saving lamps  - Page 1
Forum section: electronics / beginners

author: Vtile
author_rank: Super Contributor
timestamp: May 29, 2017, 02:18:00 pm
content: I wonder how these energy saving lamps and LED-lamps withstand in a longer run stray voltages. I would assume the possibility of stray voltages of the wirings is taken account and atleast lamps from respectful manufactrurers should be designed in a way that there is no circuitry that would be damaged from prolonged stray voltages (0 - 60 Vac or dc), which are dominant in cases where the light switch is off-state, but other cabling generates stray voltage for the lamp branch. The question is of a phantom voltages, so it doesn't have a "any" (as looking of from direction of mains powerlevels) power behind it.Does anyone know if there is any international/EU/US/other standards that gives any "quarantee" on this.In other hand I can not get to my head if there is actually any circuitry or component that might suffer from such a voltages.

author: Zero999
author_rank: Super Contributor
timestamp: May 29, 2017, 06:10:54 pm
content: I don't see how stray voltages could possibly pose a problem for energy saving lamps. Do you have any references to anything which says it is a problem?Stray voltages are caused by capacitive coupling and have a very high impedance and LEDs will emit visible light at tiny currents, so it's possible the lamp may glow very dimly, even when it's switched off. This will not cause any harm to the lamp and the power consumption will be tiny.

author: Vtile
author_rank: Super Contributor
timestamp: May 29, 2017, 06:57:56 pm
content: Quote from: Hero999 on May 29, 2017, 06:10:54 pmI do not have found any sane/technical discussion or article that would state anything (to direction or another) about it, that is the reason. This arises from the educational problem, once you have certain degrees on your backpocket your phone starts to ring when friends have questions. This is one of those and I couldn't find any answer on my own (or can't reason the subject to direction or another).With old incandescent light bulbs this is not even worth to consider, but these new replacements seems to be all over the place what comes to quality and internals (especially LEDs), but I have not studied the subject on my own nor in formal studies.The last sentence is mostly what I'm after ... is the fluerescent or LED lights electronics designed in a way (is there even a standard for the internals or worst case limits) that they withstand the lower than nominal voltages (or in this case high impedance stray voltages) at prolonged periods.I can not think any component that wouldn't withstand it, but I can't claim to know everything. Is there any resource that could act as a starting point (if any).Edit: I just found out that CFLs (I just found this acronym ... damn, Anglo-Saxons with million and one three letter acronyms.) cause cancer, apatia, health issues and loose morale in bedroom, but I'm still trying to find something technical (articles or something) from respective sources.. (my quess that there is no such for these political enlightenments from ChinaExporters.)

author: Zero999
author_rank: Super Contributor
timestamp: May 29, 2017, 08:59:47 pm
content: Quote from: Vtile on May 29, 2017, 06:57:56 pmBecause there aren't any issues with LED lamps and stray voltages due to capacitive coupling?The LED lamp will also reduce the voltage when its connected to the circuit, so the actual voltage will be much lower than that measured by a meter connected to some wire with nothing else in the circuit.

author: Vtile
author_rank: Super Contributor
timestamp: May 29, 2017, 09:21:51 pm
content: Quote from: Hero999 on May 29, 2017, 08:59:47 pmThat is propably the case, but from electrical point of view I wouldn't care less of EMIs and such, but I'm only interested if it burn or does it give a electric shock.If the internal circuitry of the bulb happens to have high impedance in general and some capacitance (electrolytes seems to be in many tear apart pictures), it might do something not wanted in a long run.Quote from: Hero999 on May 29, 2017, 08:59:47 pmYep, This is something that can be seen with 10 meg dmm, but not with 100k AVO8. I can not remember how much I calculated the power on it, not much at all. I just don't know the typical internal circuitry of CFLs or LEDs to judge and how wild the field (CFL/LED quality) is atm. (I would assume it is getting better).I'm making some progress with my search now when I start to find the right keywords.

author: Zero999
author_rank: Super Contributor
timestamp: May 29, 2017, 10:29:03 pm
content: Quote from: Vtile on May 29, 2017, 09:21:51 pmHow about looking at some schematics for LED lamps and figuring out what would happen if they were connected to the mains via a small capacitor, which is effectively what's happening? There are two different topologies for driving LEDs from the mains: a switched mode converter and a capacitive dropper.If the LED has a switched mode converter then the tiny current will most likely be shorted circuited by the X capacitors, required for RFI suppression. If the LED uses a capacitive dropper, then the effect will be the same as reducing the ballast capacitor to a very low value and the LED will light very dimly.