Aha! Someone who understands!


That's a great idea. Tomorrow.


I started this thread well in advance of needing the actual answer.

Thanks!

I'm rereading your info. I need clarification. I'll assume you are located in an industrial area and your buildings service is 3 phase 208. I'll also assume you have a 220 outlet in your office that actually provides voltage 208 that you have verified. Illl also assume the outlet is not 3 phase.

I cannot see where you supplied any info about what country these amps were designed for.

I'd call ML and ask. Your solution may be very simple. Ie voltage switch internally, movable jumper, etc

If you don't get an easy solution from them, go to the Acme site and add the needed info. Your converting single phase 208 to 240. A single buck boost should do it.

I wanted, separately, to address the LED situation. I didn't want to get into a discussion of the amps or other products. That's why I didn't give much info on the actual stuff.

I don't understand what you mean when you speak of movable jumpers, etc. I don't get how I could take American power at 208 volts and make it work on an amp designed for 220 to 240 volts, especially if I I give it power that's not the same as what we'll find overseas, because I need to supply power in the proper voltage range to test the current draw as we'll find it over there. If I wanted to move jumpers or otherwise not test the amps we will actually be using over there, I could have ordered 120 volt amps, tested them, then ordered 220 volt amps for overseas. But then I would not have tested the actual amps I'm sending over.

They are JBL amps, made for use anywhere in the world with reliable power. These versions are for 220 to 240 volts at 60 Hz. Other versions are available for other power inputs, but we'll ahve 240 volts at 60 Hz. I'll look up and supply the model numbers when I have time.

Who is ML?

You said Mark Levinson. I went to their site and it does not seem as if they make anything designed to work off of three phase. 240 yes, 3 phase no.

If the amps run off 240 60 hz then take them home and plug them in. 99.99% of American homes have 240 volts.

WTF does the plug look like?

Call me if you want and I'm sure this can be worked out in a matter of minutes.

Many electronics do not work off the wall current. They actually have power supplies that change the wall current( primary voltage) to what the devices actually needs( secondary voltage). There may be an easy way internally on the amps to do this. Look at the power supply of a pc- most can be swapped from 120 to 240 with the flick of a switch. PCs use a mix of 5 & 12 volts but never 120 .

I've said all of this at least once, but apparently not clearly enough. Let me rephrase it.

I've got a projector that draws about 23 amps at 220 volts...or so. I've got JBL and Mark Levinson amps that draw, according to the manufacturers, a total of about 60 amps. Yes, each one of those devices, and the entire thing, will consist of single phase power.

Does anyone have more than eighty amperes at 220 volts at home? No? I don't either! Please stop suggesting that.

I've got three Everest speakers to break in. I've got eight 18" JBL subwoofers to break in. That means at least 80 dB for several hours, and probably 100 dB for an hour or so. I've got ten surrounds to break in.

Does anyone want to do this at home? In their neighborhood? If I could, I would not want to because it would be too f#*king loud and would be the kind of thing that would make people want to come and rob me. It would also likely break some of my windows and loosen some fillings.

Let's now refocus on the power the way I've proposed it.

The power amps come with several IEC to Euro-ish plugs. We will be using the Schuko plugs. Since I'm working out a temporary power solution for testing only, I'm using a plain old American power strip and IEC to American plug for each device except for the projector.

The projector has a 30 amp male twist-lok on its chassis and comes with a four-foot twist-lok cable. It's up to me to get the juice there.


Again, repeating myself, again (again!): The low power devices have power supplies that run off of 100 to 240 volts, so I will just plug them into whatever I've got.

The devices that run off of higher voltages need to be tested with those higher voltage inputs in order to characterize their actual current draw at those higher voltages. Moving a jumper will make it impossible for me to measure what I need to measure.

Oops. I see that I said all that stuff in a different thread dealing with supplying power to these devices. This thread is about powering up a 120 volt LED with 220 or so volts.

I worked out a solution which is probably wrong. I've put a 55K resistor in series with each LED, which, on the surface, sounds right.

However, being the eternal kid that I am, I took one of the night light "bulbs" and broke off the external glass envelope to see if it would still work without it. It does. Upon examination, the thing seems to be a diode in series with a resistor.

That also makes sense, except that, in the past, the resistor would have to be too high of a wattage to work. Now that there are very bright LEDs, lower current can be used, thus the resistor can be of a lower wattage.

Anyway, back to my probable error: The thing says it draws 0.25 watts. Math says about 55K ohms is good for splitting the voltage in half. I just realized, though, that the diode makes it work only half the time, so I'm figuring full duty cycle wattage on a 50% duty cycle device. I should have calculated current at twice the rate, since I'm using power and voltage as my calculating basis.

The current will be twice what I thought it was, for 50% of the time, so the 55K resistors I put in place probably will deliver just a tiny amount of current to the LED. Hopefully it will be enough to turn it on.

No you have not. I asked 3 very pointed questions trwice. You skated them all.


You seem off on your load calcs of the ML amps. They are rated 640w max each. I got that directly from the ML website under specifications. Take that 640w divided by country's voltage, 240 and you have a whopping 2.67 amps each.



By code, the MINIMUM electrical service in a home must be 100 amps at 240 volts. FWIW I am a licensed electrical contractor. I have 400 in mine, you most likely have 200.


Get to it:)


If your fillings come out at 80db, go see your dentist:)

Just messin with you




Picture of the plug? Are you suggesting 'riggin' something to push 240v down a 110v plug strip?



OK. Did you call the manufactuer and see if it would work off of 208? Probably would with reduced bulb output. Ask them. I'm CERTAIN they have run into this before. Better yet, run it at home:)



You don't havething BUT low power devices. NOTHING is 3 phase other than MAYBE, the elecrrical service at your office but you wont tell me if that is the case. Most buildings are NOT 3 phase.



Again, the manufacturers specs give you that info. Are you simply trying to reinvent the wheel? I don't see too many devices that don't give you the proper info.

Call me if you want. I think you are making this tougher on yourself that it needs to be.

That is certainly very interesting. Along the way, though, I misread his 220W, by which he means 220 Ohms, as 220K ohms, and did some calcs.

For my money, you can just have a diode and a 220K 1/2 watt resistor. The current would be one MA, which is visible with high brightness LEDs. The power is another thing. Calcs say 220K across 220 volts results in 0.22 watts, but the diode keeps current from flowing half the time, lowering the wattage across the resistor to 0.11 watts. If you use a half watt resistor, you should be okay.

Anyway, this has been delayed by many things, but I will test this out later today. I'll let ya know. I put 55K in series with the LED built to run at 120 volts. Because of the 50% duty cycle issue, I theoretically should have put in a lower resistance. But we'll see.

Very mysterious indeed. All three LEDs pulsed on very briefly when I turned on power. All three LEDs pulsed very briefly when I turned off power.

I've got 55K ohms in series with a "120 volt LED" that is said to draw 0.25 watts. Hmmmmm.

If you are saying the LEDs no longer function, then you probably exceeded the reverse breakdown voltage of the circuit (there is probably an additional diode in series with the LED because 120 Volt is very high for a backwards voltage across a LED) and fried the LED.

Probably have to add a 1n4004 (not 1n4001) General purpose diode in series with the resistor but u first need to determine which direction or you will blow it up again.

Why not just use a neon indicator lamp?

Thanks, Gord. I did not consider the reverse voltage of the blocking diode.

edit:
All seems well. Before I worked out that I had made a dumb wiring error, three times, once on each phase, I reduced the resistance t0 33k. All three LEDs work smashingly.

Someone else mentioned a good reason for not using a neon indicator lamp. Moreover, it just didn't seem like it would be that hard to adapt a 120 volt device for 230 volts. Turns out it wasn't. There were three things to consider:
*50% duty cycle for calculating power consumed and thus current used and thus series resistance value
*wire it up correctly
*blocking diode might have too low of a reverse blocking voltage