Surge Protection

[jabbr]

6 hours ago, One and a half said:

There could a problem of definition as to what leakage currents are. Leakage currents are signs of insulation failure at 50/60Hz, classically and these are monitored by legislation/statutes.

 

Leakage currents, those that flow through protective ground are indeed specified by statutes — classic concern is in the medical field which is why isolation transformers are used. 

 

In in any case not just 50/60 Hz.

 

http://www.sunpower-uk.com/glossary/what-is-leakage-current/

 

[jabbr]

Ok, so leakage currents are the currents that flow through protective ground. (all frequencies) — surge protectors and EMI filters can increase if not done carefully (see above and/or google for schematics)

 

We think of an isolation transformer as so-called “full galvanic isolation” so how does this allow a current loop?

 

Think about that.

 

Turns out that all transformers have a degree of capacitance formed between the windings on one side and the other — frequencies can flow across this capacitance. Minimizing this interwinding capacitance improves the isolation (yes all the Topaz provide great isolation)

[jabbr]

2 hours ago, jabbr said:

 

Leakage currents, those that flow through protective ground are indeed specified by statutes — classic concern is in the medical field which is why isolation transformers are used. 

 

In in any case not just 50/60 Hz.

 

http://www.sunpower-uk.com/glossary/what-is-leakage-current/

 

Hmm... this looked different on my iPhone ... let me get the correct links:

 

1) https://www.slpower.com/App-slpower/images/whitepapers/An113 Leakage Current.pdf

2) http://www.enggjournals.com/ijet/docs/IJET14-06-01-388.pdf

 

and I've liked to this PDF which has great explanatory schematics:

https://www.computeraudiophile.com/applications/core/interface/file/attachment.php?id=24877

 

EMI filters and surge protectors can cause leakage currents given the topologies of capacitances so this is relevent to this topic: https://www.emcfastpass.com/wp-content/uploads/2017/04/Powerline_leakage.pdf

[Jim Sylva]

Everyone,

Thank you for taking the time to share your experiences and expertise.

It looks like there is an alternative path I need to investigate.

[One and a half]

Since EU/US/AU/NZ & other countries ex Japan use the TN system of earthing the neutral, we end up with the mess of leakage current (and conducted emissions at lots for Hz) being transferred to the earth via low impedance connection to the Neutral at the consumer's switchboard. The noise of course ends up on the lower side of the system. (in Grey). A far better idea is to have a high impedance between the earth and neutral IT or TT systems found in France and Japan for audio. That's another application on its own.

 

Even though the Isolation Transformer magnetically isolates the load, yes, the inter-winding capacitance here illustrated as a 0.0005 pf creates the conducted voltage on the other side of the transformer, not 'isolating' truly any more. The current to earth for 120V 60Hz is 22.6 pA. If the Isolation Transformer has a spec of say 100 pf across the windings, then the same current to ground is 4.5 uA. This level of voltage is enough to influence sensitive clock circuits. The load's linear device won't have the properties of the Topaz, so the effective current can still be maintained. So it pays to use the correct type of transformer, if there is one to find!!

 

If any switching device is mounted to the frame in the equipment, the capacitive coupling between the switching device and the frame, can be diode, transistor, IC and so on. The noise voltage of course unless filtered, ends up on the circuits which we hear and creates 'noise flavour' to SQ. 

[Speedskater]

On 10/5/2017 at 10:41 PM, One and a half said:

A Topaz/Xentek/Elgar type isolation transformer is all you need for surge protection

Isolation transformers have nothing to do with surge protection!

[One and a half]

12 minutes ago, Speedskater said:

Isolation transformers have nothing to do with surge protection!

You don't read the fine print on the specs of these transformers,  as they are specifically built for surge protection. 

[Speedskater]

How is that possible unless it's a transformer and a surge protection circuit. My Xentek 5000VA isolation transformer doesn't have any surge protection.

[Speed Racer]

5 hours ago, Speedskater said:

How is that possible unless it's a transformer and a surge protection circuit. My Xentek 5000VA isolation transformer doesn't have any surge protection.

 

From an MGE (Topaz) Ultra Isolator Noise Suppressors brochure:

 

"These products can reduce a 6,000 volt spike to an insignificant 0.0030 volt."

[Speedskater]

I don't see anything about:

UL 1449: Surge Protective Device

In the Topaz manual.

[Speed Racer]

Look here....

[Speedskater]

Nothing there about AC power line surge suppression. I think that Topaz is referring to (what we call) common mode noise.

[Speed Racer]

Do some research for yourself....

 

I found this:

 

"The Institute of Electrical and Electronics Engineers (IEEE) 587 states that “6000 volts is the largest transient that the interior of a commercial building would experience, and that it’s harshest interior surge environment is one that would experience 100 surges of 6000 volts, 3000 amps in one years time”. Factory environments can experience this quantity of surges in one months time. As a result of this, a standard of how to test surge suppressers has been put into place."

 

It's not about common mode noise.....

[One and a half]

There are graphs at headfi showing what's left after an impulse of several kV. Before UPS went cheap, the Topaz was the only device that was passive and protected computers,  like the VAX8500 or PDP750.

Common mode noise reduction is 140dB, another bonus. 

[TubeLover]

Just to be clear, the Topaz that John Swenson was referring to is not the inexpensive unit made by Tripplite. Here is what he said in the other thread:

 

"The direct descendant of the Topaz is the Eaton Power-Suppress 100 series. They are the same transformer but enclosed in a rectangular metal box. They are in current production and several online companies sell them. They are not cheap ($600 range) but are brand new. If you want ones that plug into an outlet and have its own outlets make sure do NOT get a hardwired version. You can get both types, but a couple places just have the hardwired versions."

 

JC

[Ralf11]

Like this?

http://www.nextwarehouse.com/item/?285189_g10e

 

I can't tell if it needs to be wired in or not...

[One and a half]

1 hour ago, Ralf11 said:

Like this?

http://www.nextwarehouse.com/item/?285189_g10e

 

I can't tell if it needs to be wired in or not...

Why not visit the manufacturer's site to investigate further instead of asking the obvious, Mr. One Sentence Man.

[Ralf11]

Thx, Jerko - very helpful

[occamsrazor]

Not sure where you are located which may affect product availability, but.... Just to throw some alternatives into the mix....

 

https://www.sollatek.com/products/avs13/

https://www.sollatek.com/products/avs30/ (same but for whole house)

https://powermatic7.com/product/p6me/ (aother company's model, similar to AVS13)

 

I also have frequent power cuts and unstable voltage. As you point out it's the "rush" when the power comes back that is frequently the issue. These are a different type of surge protector than most, my description may not be perfect but they are essentially microprocessor controlled relays that fairly instantly cut the connection completely if there is a surge or also under/over voltage levels. More importantly they have a timer that only reconnects the supply once it has been stable and within range for around 10 secs (timer adjustable on some models). They are commonly used all across the developing world. My house is wired with the whole-house AVS30 one and it is excellent, but I also use the individual ones.

 

I also have NC400 ncore amps, in my case monoblocks, and use the Powermatic P6ME on each one. I did look into this when I built them, and from what I read the NC400 power supply (SMPS600) is actually pretty resilient, with various inbuilt protection mechanisms. I can't remember if it's the NC400 itself or the SMPS600, but one of them conducts internal startup tests to determine if voltage is OK and only then engages the main circuit. This is the slightly delayed "click" ON when you start them up. That said I still feel more comfortable having them connected via the protectors mentioned. Do they have an audible effect? Honestly I've no idea but not that I can hear.

 

As an aside, I also use one of these to correct under/over voltage and keep the house running during long periods of those conditions:

 

https://www.sollatek.com/products/avr-single-phase-1amp-to-10amps/

 

As well as some APC UPS for battery backup on the computers, but not the NC400 amps. If the power goes out completely music isn't a priority.

 

PS - I've no connection with Sollatek (!), am just a happy customer of their products...

[jabbr]

On 11/2/2017 at 8:04 PM, Ralf11 said:

Like this?

http://www.nextwarehouse.com/item/?285189_g10e

 

I can't tell if it needs to be wired in or not...

 

It says hardwired, so yes. You probably want the one with receptacles. It replaces the "H" with an "R" in the manuf code.

[GerFod]

I am a domestic electrician. I can tell you that many people misunderstand the term leakage current.

I recommend reading the correct information on this subject at: https://www.asutpp.com/leakage-current.html

 

It is important to know that absolutely any functioning electrical equipment has a leakage current under normal conditions. The maximum leakage currents for various electrical equipment are regulated by different standards.

Example:

 

Quote

The following are typical examples of leakage current levels likely to be produced by common appliances [IEC TR 62350-2006]:

 

• 1 mA to 2 mA for computers;
• 0,5 mA to 1 mA printers;
• 0,5 mA to 0,75 mA for small portable appliances;
• 0,5 mA to 1 mA for telecopiers;
• 0,5 mA to 1,5 mA for photocopiers;
• about 1 mA for filters.

 

 

Many people, when they talk about leakage current, mean earth-fault current.