EMF radiation from inverter?

[inetdog]

There may be a small transient voltage at the moment when the ringing machine is switched into series with the circuit, before it gets to the time interval where the ringing voltage is present. And if you were listening carefully on a butt set you might hear a click. But certainly not any kind of voltage change that lasts a second.
As you note, if the 48V were taken away there would be no way to determine when the phone was answered.
Also, I suppose that in a modern exchange the CallerID data might be transmitted before the first ring in addition to between rings. That might also be detectable.

[bcroe]

Complete BS Bruce. 48 volts is on the the line at all times. The -48 volt battery is there to power your phone, and detect off-hook signal current when you lift the receiver to make a call, or answer a call. Quit making stuff up. Cheese and rice I have been in telecom longer than most of you have been alive.

Its not a hard regulated 48V; the station end (not the office battery) varies with the load situation. Maybe you ought to put
a scope on it like I did. And I'm older than you. Bruce Roe

[Sunking]

When a land line phone is about to be rung, it is first disconnected from the 48VDC on hook battery. Within a
second it is connected to the ringing voltage generator.

Complete BS Bruce.

48 volts is on the the line at all times. The -48 volt battery is there to power your phone, and detect off-hook signal current when you lift the receiver to make a call, or answer a call. Quit making stuff up. Cheese and rice I have been in telecom longer than most of you have been alive.

[solarix]

I've tried all the rational arguments with them. It is like casting pearls before swine.... I end up advising them that they should get rid of all their electronic stuff and go live in a cave somewhere.

[bcroe]

Sure some people are more "sensitive" to a lot of different things (sound, light, smell, etc) but just
because they "feel" something does not mean it will hurt them or cause the illness that they are led to believe it will.

A few people do have some interesting sensitivities, but that has nothing to do with being harmful. A
program showed someone who could tell you when your phone was going to ring. "Answer your phone!"
that hasn't rung yet.

They didn't understand it, but credited it to future predicting. That wasn't it, but I know what it was. When
a land line phone is about to be rung, it is first disconnected from the 48VDC on hook battery. Within a
second it is connected to the ringing voltage generator. Some people can sense that change from 48VDC,
before the ring. Bruce Roe

[jflorey2]

Bill, good to have an EMI pro aboard. Could you give me an argument that will convince all the smart-meter fear mongers in my area that they don't need to worry about the EMI hazard of the new APS electronic AMI meters?

You might point out that cellphones emit the same sort of signals and are far closer to your head.

You might point out that if they were to wrap their bodies around the meter they might be exposed to as much as 100mW of non-ionizing (i.e. "safe") radiation - and by lying in the sun they are exposed to 50-100 watts of deadly cancer-causing ionizing radiation.

You might point out that they get exposed to far higher levels of ionizing radiation every time they fly.

The utility can't absolutely prove the meters are safe and the anti-meter people can't prove they are dangerous so we have a real controversy stirring in my community.

Of course the utilities can prove (to any sane level of scientific validity) that the meters are safe. People don't care.

[DanKegel]

I am just not afraid of vaccines

Good, me neither!

[Sunking]

Bill, good to have an EMI pro aboard. Could you give me an argument that will convince all the smart-meter fear mongers in my area that they don't need to worry about the EMI hazard of the new APS electronic AMI meters?

What is there to be afraid of from a health POV..


SMART METERS communicate via RF links. Many have a contract with the Local Cellular provider, meaning they have a small dedicated cell phone inside them. Others use the Paging Frequency bands once used by Radio Common Carries aka RCC which were put out of biz by cell phones. Others use their own licensed Radio Frequencies operating in the same 700, 800, 1900, and 2400 Mhz band Cellular, Biz, and government use. Lastly rural Coops may use what is know as Power Line Carries that have been in use since WWII.

Bottom line it is all low power RF and is no more of a threat than your cell phone. In fact with a cell phone stuck to your ear exposes your brain to 60 to 80 Db more power than your meter does. FWIW 60 to 80 Db is 1,000,000, to 100,000,000 times more power count the ZERO's. So if you are afraid of your electric meter, put on your TIN FOIL HAT when you talk on your cell phone. The electric meter is of no concern health wise. Your security and privacy is another issue, big brother is controlling and spying on you.

Lastly do not confuse EMF with RF. Two completely different things.

[SunEagle]

SunEagle's right: it's a matter of trust, just like many other science vs. activist disagreements (e.g. vaccines or climate change).
Many people find collections of heartfelt stories more convincing than actual expertise and scientific evidence.

Touche.

But to be clear. It isn't a trust issue. I am just not afraid of vaccines or climate change. And won't be bullied into making rash decisions on those topics.

[wblanford]

The APS electronic meters are no different that any other electronic equipment. They have to pass to FCC EMI requirements. I can think of no reason why one would be more concerned with those than any other piece of electronic equipment. There have been numerous studies relating to the effects of living close to high voltage transmission line. None of those studies have shown a correlation between living close to power lines and health issues. Of course all the studies recommend further studies.

[DanKegel]

SunEagle's right: it's a matter of trust, just like many other science vs. activist disagreements (e.g. vaccines or climate change).
Many people find collections of heartfelt stories more convincing than actual expertise and scientific evidence.

[SunEagle]

Bill, good to have an EMI pro aboard. Could you give me an argument that will convince all the smart-meter fear mongers in my area that they don't need to worry about the EMI hazard of the new APS electronic AMI meters? (let alone the magnitudes higher inverter emissions) So far, I haven't found a way to break through their mindset and have lost more than a few solar jobs because the utility will not allow grid-tied systems without a meter upgrade. They don't take my word for it and I'm a former Avionics engineer with EMI testing experience, they don't listen to any industry experts because they are "obviously" biased and corrupt. The utility can't absolutely prove the meters are safe and the anti-meter people can't prove they are dangerous so we have a real controversy stirring in my community. I get the "Oh - I can feel the negative vibrations" all the time. We have a little emi meter that demonstrates how the emi from the stuff they fear is negligible compared to their cell-phone/laptop/LED lights/car etc etc but you can't argue with their feelings. The irrational mindset (as in the OP in this thread) makes me really wonder....

All the EMP/grid-down fears lately have been good for the off-grid side of our business though. Vanity/Jealousy/Lust/Greed/Fear - the foundation of sales and advertising...

Unfortunately it comes down to a "trust" issue. A lot of people do not trust their POCO or any government official in general.

Most of those people are easily scared and can be convinced of something if it comes close to one of their fears. Sure some people are more "sensitive" to a lot of different things (sound, light, smell, etc) but just because they "feel" something does not mean it will hurt them or cause the illness that they are led to believe it will.

[azdave]

Usually, the people online complaining loudest about those EMI meters usually do so with a laptop across their legs while snuggled up in a warm, cozy electric blanket.

[solarix]

Bill, good to have an EMI pro aboard. Could you give me an argument that will convince all the smart-meter fear mongers in my area that they don't need to worry about the EMI hazard of the new APS electronic AMI meters? (let alone the magnitudes higher inverter emissions) So far, I haven't found a way to break through their mindset and have lost more than a few solar jobs because the utility will not allow grid-tied systems without a meter upgrade. They don't take my word for it and I'm a former Avionics engineer with EMI testing experience, they don't listen to any industry experts because they are "obviously" biased and corrupt. The utility can't absolutely prove the meters are safe and the anti-meter people can't prove they are dangerous so we have a real controversy stirring in my community. I get the "Oh - I can feel the negative vibrations" all the time. We have a little emi meter that demonstrates how the emi from the stuff they fear is negligible compared to their cell-phone/laptop/LED lights/car etc etc but you can't argue with their feelings. The irrational mindset (as in the OP in this thread) makes me really wonder....

All the EMP/grid-down fears lately have been good for the off-grid side of our business though. Vanity/Jealousy/Lust/Greed/Fear - the foundation of sales and advertising...

[wblanford]

I'm not concerned from a personal health aspect, but I keep some sensitive equipment nearby for work and hobbies.

All electronic equipment that could be used by consumers, including inverters are required by the FCC to be tested for compliance and labeled for electromagnetic interference. All home equipment is tested to FCC part 15 class B. FCC testing only tests above 450 kHz for conducted emissions (noise on the power lines) and above 30 MHz for radiated emissions (noise radiated into the air). The main concern of the FCC is interference to receivers. The inverters convert dc from the panels to 60 Hz by switching and filtering the output. Although the output is 60 Hz, there are a large range of harmonic frequencies that are generated by the switching and control circuitry. There are also low frequency magnetic fields generated. Although there are no health issues related to low frequency fields, operating electronics that is sensitive to low frequencies and receivers should not be placed next to the inverter.

I am new to this forum, but I am an Electromagnetic Compatibility Engineer (EMC).