Transformer Hum

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Lurcher300b
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Re: Transformer Hum

Unread post by Lurcher300b » Mon Jun 11, 2018 12:57 pm

I am not talking about solar panels
but the inverters that convert from DC to AC are the same as used by solar panels.

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Dr Bunsen Honeydew
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Re: Transformer Hum

Unread post by Dr Bunsen Honeydew » Mon Jun 11, 2018 1:26 pm

I bow to your greater knowledge, but I think you miss my point. My point is the source impedance and speed of reaction of thousands of batteries compared with the output of the panels or even I was hoping our mains supply. If you put a couple of solar panels above a Formular E car how fast would it be???

It has been proved apart from to a few people that in most circumstances a mains regenerator will sort out problems and even give better music. I am looking to this as a better solution, I don't know if it will be I am DISCUSSING it.

Lurcher300b
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Re: Transformer Hum

Unread post by Lurcher300b » Mon Jun 11, 2018 3:21 pm

My point is the source impedance and speed of reaction of thousands of batteries
Yes, that would have a very low impedance, but my point was it doesn't matter if you only get to see the power of the battery via a inverter, so in this case the limiting factor is the inverter.
If you put a couple of solar panels above a Formular E car how fast would it be
Not sure what you mean, but a single panel might produce 250W in bright sunlight. The peak power of a Formula E car is limited to 250 kW, so the peak power of the car would need 1000 panels to produce. Ignoring the drag of a single panel, I think the answer to "how fast would it be" is not very.

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Dr Bunsen Honeydew
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Re: Transformer Hum

Unread post by Dr Bunsen Honeydew » Mon Jun 11, 2018 4:39 pm

But the inverter has masses of VA pass ability, it must have as this is for powering a house with electric fires etc not like normal inverters used in caravans etc. It has to be better and lower impedance.

My point was aimed at those who thought I was referring to solar panels. The solar panels are like a trickle charger for this thing.

Lurcher300b
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Re: Transformer Hum

Unread post by Lurcher300b » Mon Jun 11, 2018 4:55 pm

Yes, agreed, looking at the spec its good for 5.8kW, so thats 25A, so it can certainly push power out. No idea how fast it will react to a change in load, I would think again that the inverter will be the bottleneck on that. But again, no idea how good the AC from them is, not sure if i have ever seen it mentioned.

If a typical solar installation is 3.5Kw, then the inverter connected to that is going to be rated at a not trivial 15A, so I would think a solar array on a sunny day would be a good approximation to what a power wall is going to be like WRT powering a hifi.

If Fretless has 33 panels, then that a potential 8.25Kw or 35A (far from a trickle), and if that makes his HiFi hum a little it doesn't bode well for the future.

You may be underestimating the voltage and current that a PV array works at, a typical connector is rated at 22A 1kV.

Lurcher300b
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Re: Transformer Hum

Unread post by Lurcher300b » Mon Jun 11, 2018 5:11 pm

I just looked up the specs for a couple of 3.5Kw inverters. One quoted <1.5% THD and the other <5% THD on the output.

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Dr Bunsen Honeydew
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Re: Transformer Hum

Unread post by Dr Bunsen Honeydew » Mon Jun 11, 2018 5:15 pm

My point is to be quiet it has to have the wall unit with its massive capacity between, this I see as the future. Have you seen the products they have developed for the Grid companies.

I am not saying anything WILL be better, but my instinct and gut feel tells me it will probably be better. Well better than the shit mains I have here now. Boy Friday laughs at it, it plays tunes via the transformer coils, not only continual changes in volume but it even changes slightly in note. Your DC Blocker made no difference, my BMU makes some difference. Anything up to 300va is tolerable but the 1000va I use are like 50hz speakers.

Back in Epping this didn't happen I had very little problem. I have made two complaints and different conversations with them, all they can offer is a box that records voltage fluctuation, they refuse to accept their supply is unacceptably polluted. Can you imagine the public reaction if brown water came out your tap, well I have brown lecky coming out of my sockets.

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Dr Bunsen Honeydew
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Re: Transformer Hum

Unread post by Dr Bunsen Honeydew » Mon Jun 11, 2018 5:17 pm

Lurcher300b wrote:
Mon Jun 11, 2018 5:11 pm
I just looked up the specs for a couple of 3.5Kw inverters. One quoted <1.5% THD and the other <5% THD on the output.
To be honest I am not interested in what it measures only with what it makes my system sound like. I have found specs to be not very useful in this process. Anything to do with mains I have found the bigger the better, no matter what.

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Fretless
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Re: Transformer Hum

Unread post by Fretless » Mon Jun 11, 2018 6:45 pm

My audible hum is only on sunny afternoons when the panels are producing more than 5 kW. Otherwise the audio systems produce no unusual mains-induced noise.

When a cloud passes over and the sunshine returns then I get a 'start-up' buzz which quickly fades.
NVA: P50sa - SSP - A40 - LS6 - Cube3
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Dr Bunsen Honeydew
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Re: Transformer Hum

Unread post by Dr Bunsen Honeydew » Mon Jun 11, 2018 7:11 pm

Nick I sold you something last summer that I thought might make be great improvement, but it was too big and heavy for me and I had no room for it. It seems it is still at MCRU. That would be worth experimenting with.

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