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220V vs 120V - Any benefit?

whoaru99 said:
Came in the mail today.

A quick check using the milk house heater dummy load showed virtually the same voltage readings as the Fluke 87. The wattage stabilized at 1427 watts vs the dataplate rating of 1500 watts.
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Cool....I think I am going to get one of those....helpful to id the power sucking items in the house.... My central AC was killing me until I rebalanced the air flow.... that simple act of rebalancing the air flow saved me 100$ a month on the electric bill.... I am hoping it does the same for the gas bill....

Also, tonight I will test a toaster oven.....look at the current signal for it with the o-scope....

The current signal for a resistive load like a heater should be a Sine wave that follows the Line voltage....

It is a spare toaster oven I use to bake(cure) parts in.... :) ..... the wife would kick my butt if I ever did that in the kitchen....


jk
 
I haven't read this entire thread so excuse me if I am repeating something.
My house is all 20 amp 120 volt circuits with 12 gauge Romex. So, I should have 2400 watts available on a dedicated circuit. The amplifier should be at least 50% efficient. So, should I not assume that I would be able to run 1200 watts continous output hypothetically at 120 volts? Wouldn't 240 volts be a little overkill for this?
 
whoaru99 said:
Depends on if you get a tinge of OCD going on about voltage drop. ;)
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Hehehehehe.....OCD. :D ......... I like to think of it as "Shavings make pile....find enough of the shavings and you have one heck of a pile." but OCD works too..... Also, this is what happens when you have as much test equipment in your basement as Vintage HiFi gear......


The real question is now that one has almost run its course....whats the next Pile to OCD over....... :)


jk
 
ZeroJunk said:
I haven't read this entire thread so excuse me if I am repeating something.
My house is all 20 amp 120 volt circuits with 12 gauge Romex. So, I should have 2400 watts available on a dedicated circuit. The amplifier should be at least 50% efficient. So, should I not assume that I would be able to run 1200 watts continous output hypothetically at 120 volts? Wouldn't 240 volts be a little overkill for this?
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Well that is what the whole debate is about..... The point that "Whoru99" brought up very early on is the question of what type of power supply does the AMP have....

In hindsight for me.... foresight for him.... That is one of the key points. Most old amps have a simple Transformer/Rectifier/CAP powers supply....

I THINK..... If you have a big amp, an ugly load 4 ohm load..... yes I saw / heard an improvement.....


This weekend I will be testing my friends 3000 watt system..... He has 3 amps.... I think he needs some more AC power..... His outlet (Singular) is directly under the Service box.... so that helps....

But I doubt I would ever buy an 8000$ AccruPhase power conditioner.... but this was well worth the 78$ for me....

Can your amp even support 240Vs? Even through the title is 220.... US is actually 240.... Do you have a heavy load 4 Ohm, low efficiency set of speakers?



jk
 
It's just conversation to me as I'm not going to listen to anything louder than about 1/3 volume on an SX-1250. At my age you protect your ears with a passion.

I have run 1300 watts output many times on a 120 volt circuit with an RF linear amplifier. No problems. Anything higher I switch to 240 volt.

Also, ground and neutral are two different things. You need neutral on a 120 volt to complete the circuit. The neutral tap goes back to the power company's service. If you lose neutral the only thing to complete the circuit is the quality of your ground, or lack, through the ground rod.If you lose neutral you won't like it. Neutral and ground are tied together in your distribution panel. Old two wire houses didn't have a separate equipment ground just neutral although everybody probably called it ground.
 
RMS assumes the load is trying to do "work" for 360 degrees of the source signal. Amplifiers with Transformers/ Diode Rectifiers/Caps are only using the AC power source for approximately 100 degrees of the AC source signal.

Ok here's a pic of a Toaster Oven current signal (not voltage).... It very closely matches a sine wave with the exception of some clipping in the top and bottom.... RMS calculations work very well to characterize this load because it is connected to the source for 360 degrees of the 120 Vac sine wave.

FiIXFrxlu1GROuzv58LhdruxWjUL8mtz0300.jpg



Below is the pic of the AMP's current signal (not voltage) on a 240 Vac circuit.... It looks nothing like a sine wave because the Rectifiers are actually disconnected from the transformer for about 260 degrees....the spikes are a surge of current to re-charge the caps. All of the "work" is being done in 100 degrees of the AC source signal, not in 360 degrees as assumed in RMS calculations. This would be the same issue for 120Vac, just that the current spikes would be much higher...about twice as high.

The nature of the load current causes RMS calculations to miss represent the Voltage drops during the specific time of the current Spikes and that is the critical time that the power supply is recharging the caps.... Peak measurements are much more useful in this case to characterize the load and voltage drops...then figure out a well engineered solution.


UPsf9eVES8IMkRLOvCfNhzwVm7r9LpxV0300.jpg



For me .... I like my big honkin 20amp 240V circuit for the (cheap) cost compared to a power regulator in the thousands.....

( JUST CAUSE IT NEEDS TO BE SAID.... PLUG A 120VAC UNIT INTO A 240VAC AND SMOKE & MAYBE FIRE WILL OCCUR....IF YOU TRY THIS, MAKE SURE YOU CAN CONFIG THE UNIT FOR 240VAC....)

johnk
 
I have just read this whole thread; understood about 1% of it; and it is hand's down the most entertaining piece I've read on AK.

Thanks guys!


:)


Matt
 
jstang and MudPuppy176,
Please refrain from the insults to each other, I'd hate to have to shut this thread down, but I am on the verge.





Retro
 
I promise no more insults from me, ever again....in this thread....

Is there any Site, besides New Jersey, that insults are normal behavior....? :) Its just part of how we communicate in this State....

jk



Retro Stereo said:
jstang and MudPuppy176,
Please refrain from the insults to each other, I'd hate to have to shut this thread down, but I am on the verge.





Retro
Click to expand...
 
I was looking at Transformer type Power conditioners and came across this document.

It outlines a measurement method to determine the "peak" in rush current. Peak is very different than RMS.

In the case of the power conditioner it is critical to size it for peak loads. This is the same method I was using to measure peak Current draw by the Power Amp under load. I then used that Peak value to calculate the voltages drops and size the wiring....

My amp states typical AC power consumption of 300 watts on the back plate, but it is capable of 1200watts RMS out and has a 2.2kva transformer...300 watts in does not equal 1200watts out during a peak. I also measured the inrush current.

Running it on 240Vs ( which I am running ), at turn on it jumps to 36amps peak..... or 25amps RMS.

or

Running it on 120vs it would be 72 amps peak ..... 50amps RMS....

Now it only does this for the first 2 or 3 cycles of the AC during start up and then it tapers down.....to idle current....


http://www.pqsi.com/pdfs/IEC CVT.pdf


I know PEAK is very counter to always thinking in terms RMS, but there are times that you are better off using that measurement....Sizing AC supply for an amp with a traditional Transformer -full wave bridge - capacitor type supply is one of those times I think it is very helpful.....

Certainly you would not have to over size the line for the peak in-rush current. But 10 guage and 240Vs has its advantages in supplying power to this type of amp.


jk
 
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