AC on chassis
Juergen
My information is that in the EU and California the use of SMPS in lieu of linear supplies, is now mandated by legislation.
This information about the EU requirement came from the previously mentioned English designer. He has no choice in the matter, and has had to invest considerable R & D time to make his products perform as well as, or better than previously.
The legislators even require him to submit a quarterly report of
Waste Electrical and Electronic Equipment (WEEE) data to Valpak.
SandyK
Juergen
My information is that in the EU and California the use of SMPS in lieu of linear supplies, is now mandated by legislation.
This information about the EU requirement came from the previously mentioned English designer. He has no choice in the matter, and has had to invest considerable R & D time to make his products perform as well as, or better than previously.
The legislators even require him to submit a quarterly report of
Waste Electrical and Electronic Equipment (WEEE) data to Valpak.
SandyK
Sandy,
that exceeds my knowledge. The only thing I heard was about standby losses. This would be the extinction of transformer based wall power supplys with no or only secondary power switch. Integrated power supplies would not be affected, as you can build in a primary power switch, thus having no standby consumption.
If one needs standby, there are small transformers on the market with standby losses <1W. With these one could build a watchdog supply powering on the real supply on demand.
Regards
Jürgen
that exceeds my knowledge. The only thing I heard was about standby losses. This would be the extinction of transformer based wall power supplys with no or only secondary power switch. Integrated power supplies would not be affected, as you can build in a primary power switch, thus having no standby consumption.
If one needs standby, there are small transformers on the market with standby losses <1W. With these one could build a watchdog supply powering on the real supply on demand.
thats a really evil thing! This bureaucratic monster kills small business.
Regards
Jürgen
hm, searched a little...found this:
http://sunbird.jrc.it/energyefficiency/html/standby_initiative.htm
regards
http://sunbird.jrc.it/energyefficiency/html/standby_initiative.htm
regards
AC on chassis
Juergen
Unfortunately I can't locate all of the original information. However the part below, which was extracted from a thread by Graham Slee of Graham Slee Projects Ltd. may be of interest.
You can be fairly sertain that the same will eventually follow with inbuilt power supplies.Of course ,the cheap generic SMPS boards from China, are also a major attraction to manufacturers at the moment
SandyK
"Remotely powered products using linear power supplies are effectively banned from sale in California state under CEC law. Similar laws come into force in eight other US states, Canada, the European Union, Australia and the Far East between now and 2008."
Juergen
Unfortunately I can't locate all of the original information. However the part below, which was extracted from a thread by Graham Slee of Graham Slee Projects Ltd. may be of interest.
You can be fairly sertain that the same will eventually follow with inbuilt power supplies.Of course ,the cheap generic SMPS boards from China, are also a major attraction to manufacturers at the moment
SandyK
"Remotely powered products using linear power supplies are effectively banned from sale in California state under CEC law. Similar laws come into force in eight other US states, Canada, the European Union, Australia and the Far East between now and 2008."
Measure the voltage with an analog multimeter having about 20K/V sensitivity and u will see near nothing.
That leakage voltage has no current drive capability and will not even kill an ant, so stop worrying and start enjoying.
edit
The line tester (a screw driver with a resistor and a neon housed in a plastic casing) for detecting phase wire in unbalanced mains supplies requires u to touch its contact plate. All those electricians are waiting to die of other causes.
Gajanan Phadte
That leakage voltage has no current drive capability and will not even kill an ant, so stop worrying and start enjoying.
edit
The line tester (a screw driver with a resistor and a neon housed in a plastic casing) for detecting phase wire in unbalanced mains supplies requires u to touch its contact plate. All those electricians are waiting to die of other causes.
Gajanan Phadte
I think better check all live and neutral of your mains if all connected in phase correctly, and don;t just check the plug on power cord, also check if any transformer have worng connection to cord or IEC socket, plus and wall socket/power strip, it is no way the chassis carry voltage as long as all mains connections are correctly in phase.
AC on chassis
Goldkenn
This occurrence that lanchile07 mentioned at the beginning of this thread, is normal with DVD players etc that are powered by SMPS supplies. The culprit is the capacitor shown in red on the attached Pioneer DV 563A schematic.
The whole phenomenon was also discussed in a recent article by Silicon Chip magazine, complete with typical voltage readings and CRO photos.
It is not a fault condition , and has nothing to do with the mains wiring.
SandyK
Goldkenn
This occurrence that lanchile07 mentioned at the beginning of this thread, is normal with DVD players etc that are powered by SMPS supplies. The culprit is the capacitor shown in red on the attached Pioneer DV 563A schematic.
The whole phenomenon was also discussed in a recent article by Silicon Chip magazine, complete with typical voltage readings and CRO photos.
It is not a fault condition , and has nothing to do with the mains wiring.
SandyK
Sandyk is right!
Yes! sandy you are right! and I test it the voltage from RCA cables."I put my tong on the cable and one of my hand touching ground(primitive method) and I got some voltage like when you put it on a 9v battery(same sensation).I know this is not good idea putting your tong there but,in one of the post said it is not danger so.here I went the laboratory mouse lol.
Yes! sandy you are right! and I test it the voltage from RCA cables."I put my tong on the cable and one of my hand touching ground(primitive method) and I got some voltage like when you put it on a 9v battery(same sensation).I know this is not good idea putting your tong there but,in one of the post said it is not danger so.here I went the laboratory mouse lol.
Sandy is right.
The leakage current is coming from the SMPS on the DVD and this is perfectly normal and safe. It's a measurement artifact that we'll have to accept in exchange for saving the 1W of wasted power (hysteresis & eddy current losses) in a traditional transformer based linear supply. Think of Al Gore smiling at you!
To understand this you have to think about the circuit you're measuring. When the chassis is not connected to mains ground (i.e. a 2 pin mains plug) it floats and so forms one side of a capacitor. Everything grounded in the room (wiring etc.) is the other plate of the cap. Then when you connect a meter between mains ground and the chassis you are going to cause a leakage current to flow through the meter. Even a short length of wire in your living room has many pF of capacitance to the 120/240VAC wiring in the walls. The problem is that this leakage current flows through the meter resistance and the meter reads it as a voltage.
As Sandy points out, there is a cap in most off line SMPS designs that also causes a leakage current to flow. This is for EMI radiation prevention so that other equipment isn't interfered with
This leakage current must be below 50uA to meet UL/CSA and European safety standards and most people consider this a safe level of current limit. If it has a UL/CSA marking then it has been tested for safety and conforms to this worldwide standard.
I think there are better ways of doing SMPS to prevent this but those designs are more complex. need more components and so are expensive. You won't find them in corporate mass produced equipment
As long as it doesn't cause a hum in the audio it's really nothing to worry about.
The leakage current is coming from the SMPS on the DVD and this is perfectly normal and safe. It's a measurement artifact that we'll have to accept in exchange for saving the 1W of wasted power (hysteresis & eddy current losses) in a traditional transformer based linear supply. Think of Al Gore smiling at you!
To understand this you have to think about the circuit you're measuring. When the chassis is not connected to mains ground (i.e. a 2 pin mains plug) it floats and so forms one side of a capacitor. Everything grounded in the room (wiring etc.) is the other plate of the cap. Then when you connect a meter between mains ground and the chassis you are going to cause a leakage current to flow through the meter. Even a short length of wire in your living room has many pF of capacitance to the 120/240VAC wiring in the walls. The problem is that this leakage current flows through the meter resistance and the meter reads it as a voltage.
As Sandy points out, there is a cap in most off line SMPS designs that also causes a leakage current to flow. This is for EMI radiation prevention so that other equipment isn't interfered with
This leakage current must be below 50uA to meet UL/CSA and European safety standards and most people consider this a safe level of current limit. If it has a UL/CSA marking then it has been tested for safety and conforms to this worldwide standard.
I think there are better ways of doing SMPS to prevent this but those designs are more complex. need more components and so are expensive. You won't find them in corporate mass produced equipment
As long as it doesn't cause a hum in the audio it's really nothing to worry about.
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