## What is the correct AC input voltage for US and foreign machines?

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Something I've always been confused about was the 110V, 115V, and 120V input voltage parameters for some machines and devices. For example, looking at the bottom of my Hakko FX-888D, it specifies an input voltage of 120V and my bench top DC supply has a switch to select for input voltage, and it's set to 115V.

What is the correct way to specify input voltage? Where I work, we develop machines used for soil and aggregate testing, and our website lists some of our machines having an input of 115V, and some at 120V, and even some at 110V. In my mind defining it as 120V (or 240V) is correct since that is the only voltage that falls within 5% of 120V, which is what power stations must be able to deliver?

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Last Edited: Thu. May 5, 2022 - 02:32 PM
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This looks useful..

http://coffeetime.wdfiles.com/lo...

I was trying to make the point that UK used to be 240V but EU hamonization means that since 2003 we now conform to the 230V (-10%/+6%) across Europe

Of course the morons that now run this country will probably decide, because of Brexit, we'll now be 193V or something equally stupid just to guarantee it is "unique", "British" and not afflicted by Johnny Foreigner!

Thanks Clawson, I've seen that table before on Wiki but didn't really look too close apparently. Copied this from the link you just sent that answers my questions as to why someone might specify 115V vs 120V

Voltage ranges
Distinction should be made between the voltage at the point of supply
(nominal system voltage) and the voltage rating of the equipment
(utilization voltage). Typically the utilization voltage is 3 to 5% lower

than the nominal system voltage; for example, a nominal 208 V supply
system will be connected to motors with "200 V" on their nameplates.
This allows for the voltage drop between equipment and supply.
used on these systems will carry slightly lower nameplate voltages

Thanks for pointing me in the right direction!

In the US it's nominally 117v , but setting your equipment to 115-120v 60Hz will work just fine.

FF = PI > S.E.T

Last Edited: Thu. May 5, 2022 - 02:37 PM

clawson wrote:

I was trying to make the point that UK used to be 240V but EU hamonization means that since 2003 we now conform to the 230V (-10%/+6%) across Europe

While remaining at 240v, of course. At the same time, EU distribution is also nominally 230v +10/-6% which also - amazing! - means that 220v here also meets the same spec.

A UK toaster on EU mains is noticeably slower than it was in the UK, as is a UK kettle...

Neil

barnacle wrote:
EU distribution is also nominally 230v

I do not know how they did it, upgrade from 220V to 230V. On a local transformer, doubt. Must be on regional 110kV net.

As a consequence (back in 80's) ordinary bulbs were extraordinary quick to burn, they were not adapted, not yet.

Last Edited: Thu. May 5, 2022 - 07:31 PM

As a consequence (back in 80's) ordinary bulbs were extraordinary quick to burn, they were not adapted, not yet.

You do know about the "mafia" conspiracy to  limit bulb life??    If you were caught making bulbs that lasted too long, you would hear from "the boss" and get in very big trouble

There were continual reports of cartel members’ attempts to restore the burning time of their bulbs to the old levels in defiance of the watchful eyes of Phoebus. At one point, some members surreptitiously introduced longer-lived bulbs by designing them to run at a voltage higher than the standard line voltage.

it is of the greatest importance that we do not sink back into the same mire by paying no attention to voltages and supplying lamps that will have a very prolonged life.”

https://www.everlumen.no/the-gre...

ON 23 DECEMBER 1924, a group of leading international businessmen gathered in Geneva for a meeting that would alter the world for decades to come. Present were top representatives from all the major lightbulb manufacturers, including Germany’s Osram, the Netherlands’ Philips, France’s Compagnie des Lampes, and the United States’ General Electric.

These companies colluded, it turns out, to engineer incandescent lightbulbs with dramatically attenuated life spans: over the next years, bulbs that once burned some fifteen hundred to two thousand hours were made to last for only a thousand, thus enabling every company in the world to sell more bulbs and artificially inflate prices. The ruse lasted until 1940, and it was surprisingly sophisticated in its execution; the companies involved made “very strenuous efforts … to emerge from a period of long life lamps,” as one executive wrote.

The cartel took its business of shortening the lifetime of bulbs every bit as seriously as earlier researchers had approached their job of lengthening it. Each factory bound by the cartel agreement—and there were hundreds, including GE’s numerous licensees throughout the world—had to regularly send samples of its bulbs to a central testing laboratory in Switzerland. There, the bulbs were thoroughly vetted against cartel standards. If any factory submitted bulbs lasting longer or shorter than the regulated life span for its type, the factory was obliged to pay a fine.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Thu. May 5, 2022 - 08:28 PM

grohote wrote:
I do not know how they did it, upgrade from 220V to 230V. On a local transformer, doubt. Must be on regional 110kV net.

They didn't - Read Neil's post carefully. Nothing changed at all. It was a classic and truly brilliant example of EU fudge compromise.

• EU is 220V and doesn't wish to change.
• UK is 240V and doesn't wish to change.
• How do we achieve a harmonised EU standard mains voltage ?
Harmonisation Stage 1 For UK: 230V (-6% / +10%) Allowing 216V to 253V
Harmonisation Stage 1 For EU: 230V (-10% / +6%) Allowing 207V to 229V
Harmonisation Stage 2 For All: 230V (-10% / +10%) Allowing 207V to 253V
• EU supplies 220V and holds tolerance to (-6% / +10%). Allowing 207V to 242V
• UK supplies 240V and holds tolerance to (-10% / +6%). Allowing 216V to 254V

Here's an interesting article on how all this affects Guitar Amps

Ampworks UK wrote:
There’s no practical change to wall voltage. We’re still running 240VAC nominal through the grid, they’re still running 220VAC nominal. Everyone’s happy (except Nigel, of course).

Interesting legacy design issue I hadn't thought of; an interesting observation about what happens when you *don't* design things correctly and - major manufacturer or not - run components at or beyond their specified voltages. I guess the safe way to do this would be to use a rectified and controlled DC 6.3v for the heater voltages (that'd be high current, though) and probably the same - at high voltage - for the anode drives. It's been so long since I've designed anything so closely dependent on the mains voltage that I've not thought about this for years... probably the valve aficionados would complain about the presence of silicon in that iconic valve sound.

Neil

One thing to keep in mind is also the difference in the frequency in your home market vs foreign products. I used to live in the US and when I came back to Europe I brought my beard trimmer with me. Didn't think much of it - I plugged it into the wall socket with my adapter but the adapter only converted the voltage - not the frequency. When I turned on my trimmer it was as if it was possessed by a demonic spirit - it ran red hot in a matter of seconds before I unplugged it and figured out what was going on.

clawson wrote:
Of course the morons that now run this country will probably decide, because of Brexit, we'll now be 193V or something equally stupid just to guarantee it is "unique", "British" and not afflicted by Johnny Foreigner!

Isn't the irony of that whole idea that Britain ended up having much MORE immigration because of Brexit - just instead of it being Europeans who could hide and pretend to be British as long as we keep our mouths shut - it is now visible minorities :D?

1010001010111101110111

Mithrandir_ wrote:
Isn't the irony of that whole idea that Britain ended up having much MORE immigration because of Brexit - just instead of it being Europeans who could hide and pretend to be British as long as we keep our mouths shut - it is now visible minorities :D?
Oh don't get me started - follow me on Twitter if you want to know what I really think about the immigration/brexit/racism situation in the UK.

That was an interesting article on the guitar amps.

I’m guessing it’s heresy to ask this question… But why don’t they use some sort of regulated power supply to drive the valves? That could make the whole issue of input voltage disappear.

regards
Greg

But why don’t they use some sort of regulated power supply to drive the valves?

There are many misconceptions about Edward Van Halen’s primary amplifier used for recording. Rumors have abounded about the amplifier being heavily modified and some of these rumors were in fact generated by Mr. Van Halen himself (he admitted telling these stories to help generate business for tech friend Jose Arrendo’s shop). However, in truth according to our best knowledge, his amplifier of choice for recording, a mid-60’s 100 watt Marshall Super Lead, was primarily stock (Note: see studio diagram description for more info on this). Edward was adamant about getting his tone through the power tubes and consequently set all volume and tone controls on the Marshall to 10. He controlled the overall volume output in two ways.

First, he used an Ohmite Variac, a variable transformer that could lower or raise the voltage going into the amplifier (see photo for what a typical Variac looks like). Edward set the variac to approximately 90 volts, thereby reducing the amount of input voltage going to the amplifier (see the Marshall Super Lead article for more information about variacs and attenuators) and allowing the amp to run more reliably. A key element often not considered today when running vintage Marshall amplifiers is that many that were made for export to the U.S. were designed to run at 110 volts and current U.S. outlets run at 120 volts. As a result, while there has been much talk about the dangers of using a variac, in many applications, it obviously serves a benefit.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

avrcandies wrote:
the variac
gregd99 wrote:
sort of regulated power supply

Back to valves, you can not believe how this was different, simple, unprotected- to power variations.  The variac is the best solution, and you should adjust it (because it is how it works).

Other mode is to choose proper voltage on transformer. Here is a state-of-art for amplifier:

You may ask why is the second 6.3V section here, it is because of rectifier valves like EZ80. This one does have own filament close to cathode 270V high voltage and is normal to be separated.

Some older types have cathode connected directly to filament. Not, this 6.3V can not be regulated (but 1N4007 can help).