Further to my RFI-blasted workshop issue, I have been trying to think back to when the problem first became evident. I'm pretty sure it started happening after Christmas last.

Last night, I watched a video taken in my workshop on 20 Nov 2014 which shows AM valve radio playing happily away on 2CH with no evidence of said RFI, so if necessary I can prove that I didn't walk into a known RFI zone from the outset back in December 2013.

I actually bought a LED globe recently of 4Watt It has four bars facing down like the radiators on the phone towers: The whole being enclosed in a roundish retro envelope.

These are a new type, due to complaints about LED globes projecting most of their light away from the cap of the globe instead of out in all directions.

There will be some electronics somewhere, most likely in the bayonet cap, even if it is just a bridge rectifier, 240v regulator and some filtering, otherwise you'd be hammered with flickering at mains frequency.

This would fit well with my comment re complexity. Compare the inordinate amount of poorly thought out, or possibly cheap skating amount of electronics in a CFL that go to creating a heavy RFI generating piece of pollution. Then compare it to my previous comment.

In essence, if the LED bars are made to take the rectified voltage of the mains there might be a need to prevent DC radiating back in fault mode and perhaps some current limiting, but it requires no oscillator transformer or anything like the number of parts of a CFL that can generate RFI. Some Americans are replacing a lot of electrolytic caps with a film type, which will not dry out & last longer. So we have the potential to make a superior product with a lot less parts, potentially no RFI & using less resources.

You can still buy fancy round incandescent globes if RFI is an issue in a particular part of the home. These are usually only available up to 40 watts though.

You can still buy regular sized incandescent bulbs of the halogen type. I use them at home. I buy a stack of 52 watt (75 watt equivalent) from Aldi when they are on sale.

Here is a timely article on the subject. Seems the US is having issues as well

http://criticalcomms.cmail1.com/t/y-l-drqkkt-jiiijykiti-f/

ben

Not at all surprised there have been intermittent rumblings for a long time on the antique radio forum Re RFI

Marc

Found the bugger!

More soon ...

Should be interesting. I have at least five items in this workshop / office that are known RFI polluters, one is actually a cheap & very nasty dodgy cordless drill that also generates lots of ozone.

More garbage sold by big retailers with little concern for anything other than their fiscal bottom line: bottom line is a lot of their stock.

Do remember, if it has any sort of warranty or is advertised as being able to cut steel (some oscillating cutter blades) do take it back. Taking it back, wastes a lot of sales peoples time & costs the company money, as it stops the sales person selling something.

If a product has a large return rate (ie time loss factor costing them money) that piece of garbage will be discontinued and perhaps they will forced stock something with a bit more quality.

There are a range of cheap mowers I have seen a few of examples of (as they roll in to see if I can fix them, or see why they failed) being sold on the WEB & other places. The engine looks like a blatant copy of an old B&S engine that I have seen more than one catastrophic failure in. They have copied & used inferior components in the very areas that failed in the B&S.

Its all about price & profit now, not quality. I bought a real Honda mower in 1989 and it's one of three real Honda engines of similar age, that are showing no sign of dying any time soon.

Marc

After a bureaucratic delay of 4 weeks since I submitted my power quality complaint, no less than 3 Ausgrid engineers attended for a site visit. Their sensor was a portable AM receiver. They accompanied me around the street outside and the building itself observing the RFI problem that I reported.

In the short time they had available, the senior engineer was of the view that the source of the RFI was more likely within the premises than being imported via the Ausgrid mains feed and asked me to find a time to progressively isolate the power to each unit and to each of the house services. I found the time to do that late last night.

The source of my AM band interference problems is the building's ventilation system, comprising two large 3-phase fans linked to carbon monoxide sensors. One fan provides the fresh air supply and the other is the exhaust. Those fans are controlled by VFDs.

There are 6 other, smaller fans. They are single phase and not controlled by VFDs.

When I switched the whole system off late last night at its control panel I suddenly regained perfect AM reception in my unit, especially on my mains-powered valve set, and also the low frequency noise in my portable receiver disappeared (i.e. the sound that I recorded in the YouTube video).

I then proceeded to isolate each system component, breaker by breaker, and discovered that the supply fan's circuit seemed to be the main contributor. When it is running AM is effectively jammed in my workshop. When it is switched off at its local isolation switch, AM reception is fine, as it was when I purchased the unit back in late 2013.

The across-the-band AM jamming is so effective when it is present, I am wondering if the RFI is actually clobbering the IF? Or maybe it is overloading the AGC?

However, when the rest of the ventilation system (apart from the supply fan) remains powered up, I can still detect the low frequency noise on my portable receiver, which tends to indicate that the system is providing a smorgasbord of interference across a range of frequencies.

Ausgrid has asked if they may connect a power quality monitor in my unit in order to capture the signature of the interference before it is remedied, as part of their reference material. I'm happy for them to do that.

I'm more concerned about eliminating the source of the RFI.

Although VFDs have a well known reputation for being RFI generators, the nature of my case is not so cut and dried.

I spoke to a support engineer from the company that supplies this particular VFD and he was surprised that the problem I am experiencing only became apparent recently, given that the installation is 2 or more years old. His experience is that RFI problems, if any, are apparent from Day 1 of the installation. I told him that I have video evidence that there was no such problem back on Nov 20, 2014.

He rattled off a number of potential causes, including some sort of earthing fault. He said he is happy to assist in chasing down the cause, if I can provide him with the system's wiring diagram. I'll have to get that from the developer.

To be continued ...

What I have in several places to get rid of RFI & surges here:

An MOV N to A; Another MOV A to E; 0.1 or 0.2 mfd mains types N to A; 0.01mfd N to E; 0.01mfd A to E.

One MOV is set too, and two units have, tripped the RCD to kill the circuit with a big surge. Flame proof boxes.

Marc

From what I can tell, the combination of RFI effects that I am experiencing is partly radiated from the building's ventilation plant cabling (some of which runs into my unit) and partly imported into the set via the mains.

My aim is to be rid of all of it. At this stage I am going to concentrate on getting remediation via the supplier/installer of the equipment.

It will be good if they can sort it? I was concerned with my devices, as to the size of the surge (source not known) that was able to cause two of them to trip RCD's that trip at 30mA.

Do note my devices are to cover two problems. MOV's have been known to explode, hence the metal or fire resistant housing (containment).

Marc

Do note my devices are to cover two problems. MOV's have been known to explode...

https://upload.wikimedia.org/wikipedia/commons/6/63/Varistorfail_full.jpg

They sure do go 'pop'.

Brad, your image link didn't work for me, but this one does:

https://en.wikipedia.org/wiki/Varistor#/media/File:Varistorfail_full.jpg

I saw a varistor blow itself into two halves on a mate's bench only 2 days ago. He'd wired a component around the wrong way, creating a dead short.

Both links lead to the same image. Not sure why it's not working for you, as it is a direct link to the image and Wikipedia doesn't block image hotlinking. Anyway, good to see you still got to see it.

The side of that component got quite hot for a millisecond or two. You'd want your eyes shielded when they flame out, that is for sure.