Just had installed three new DC fans, two Arlec, one Mercator.

The Mercator produces interference throughout the house, a chopping sound as it comes up to speed and frying thereafter. The Arlecs are OK. Of course the Mercator is on a very high ceiling.

Hi STC,

Interference unfortunately is part and parcel from many modern electronic power supplies.

The frying sound should be investigated, may be normal but long experience with 'frying sound' may be indicative of low level arcing.
Hopefully not, but I would keep an eye and ear open on that unit.

Thanks for the tip. No sound out of the switch and the fan too high up to tell. A somewhat similar sound to some LED lights so I didn't think of arcing.
I will keep an eye and ear on it.

Sometimes light and GPO switches arc before final failure.

The post in case someone might want to put in some mitigating caps during installation.

I have had considerable issues with LED's & their power supplies. There seems too be an obsession with switch mode & pulse width. I do wonder how much energy is used & resources consumed making them when a simple diode string & a cap may suffice?

DC fans are quieter than their AC brethren because there is no whirring noise in the motor caused by triacs inside the dimmer mechanism. There are two types of dimmer mechanisms for AC fans too, both being for the shaded pole type motor which ceiling fans and the smaller exhaust fan motors are known for. Such motors are pretty gutless but generally give many years of good service.

It does not surprise me that DC controllers give off boundless amounts of electrical noise. Remember where cheap brands like Mercator and Arlec are made. Arlec once made all its products here but that went out the door years ago. There is a law against this but there is no-one to enforce it.

All the ceiling fans I've seen use an autotransformer in the switchbox. The switch simply selects a transformer tap.

They can get a little warm but seem to last forever - I've never had a failure.

They seldom come with those anymore. Usually they come with a fake Clipsal or HPM dimmer mechanism. They rarely failed which is why they don't make them anymore.

The fans replaced were speed controlled by capacitors that were switched to give three speeds. Only replaced because the die cast blade spider sagged and cracked. Only electrical noise was off peak switching tone.

The capacitors failed over time causing the speed to slowly decrease. Replacing these caps fixed that problem.

The problem with the ones with the switched condensers is that they will only work well with the fan they came with. I did some experiments a long time ago and found that if you controlled a 900mm fan with a controller from a 1500mm fan then there was far less control over the speed due to the weight of the blades. The smaller fan would simply run at full speed on all settings even though it had the same motor as the fan with the larger blades.

This won't be a problem when only one size of fan is installed but back when that control method came about I won a job to fill a small commercial office space with different sized fans and made the mistake of unpacking everything at once and then installing it all. Some fans worked as intended and others were not working so well. Sorting out all the swapped controllers fixed the problem after a lot of messing about.

The ancient Marelli ceiling fan here was actually designed for a "Carbon Pile". It now runs a modified wave form type. Interesting:

I have Wireless NBN. In order to calibrate a radio, you shut of the computer, the UPS, the NBN entirely, and a Flouro light bank as one has yet another unreliable piece of junk called an electronic ballast. Since the house was built in 2012.

Every flouro fitting inside it has been replaced & the four under the verandah & one modern one in the shearing shed need tossing. Yet the original 1960's flouro in the shearing shed and an 8ft one in another continue.

Marc

Forgot. A brushless DC fan here was four pole and had a fixed peripheral permanent magnet The poles were driven by an oscillator.

First generation electronic ballasts (which mimic rapid start fittings with filament transformers and not the more commonplace switch start fittings with starters) were crap. Later and current versions are much better, though it is all obsolete with the move to LED fittings.

I miss the older 6 and 8 foot T12 tubes - very bright and reliable, though control gear is no longer made for them. They stopped making the tubes for them about 15 years ago too, though I think some are still made in the third world and can be purchased on Ebay.

From this thread I believe manufacturers have finally worked out how to make products fail quicker! Valve radios were initially meant to have a 5 year life span yet many of them are still in existence and a large proportion are nearly 100 years old.

My oldest is from 1925 - making it 98 in round figures.

I am still yet to hear anything about what should be getting celebrated in November this year - 100 years of AM radio broadcasting in Australia. With some of the warped priorities of our federal government at the moment - I doubt it'll be even a blip on their radar.

Oh come on now Brad, be fair to our Guv, they are doing a grand job in the midst of an impending energy crisis, housing shortage, spiralling national debt, runaway youth crime, overloaded hospitals, our Guv is doing critically important stuff like figuring out how many more genders can be added to the list, how to get rid of Australia Day, how to suck up harder to the United Nations, yep, real priorities.

But back to Carl's comment, I couldn't agree more mate. My flagship Stromberg Carlson turns 75 this year. Born in Sydney 1948, still working
with original caps (even the paper ones) and outperforming the rest of my fleet.