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groingo
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# Posted: 9 Jun 2015 06:16pm - Edited by: groingo
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OK, it's hot, my brain is hitting a wall, question is: is 5 amps the same at 110 volts as 5 amps at 12 volts...is an amp just an amp?
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Tarmetto
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# Posted: 9 Jun 2015 07:52pm - Edited by: Tarmetto
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amperes = watts (power) divided by voltage (AC or DC)
You can't convert volts to amps since volt and amp units represent different quantities.
This will answer your question...
http://www.candlepowerforums.com/vb/showthread.php?219445-Converting-AC-amp-ratings-t o-DC-amp-ratings
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Bzzzzzt
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# Posted: 9 Jun 2015 07:59pm - Edited by: Bzzzzzt
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Groingo: Amperage and Voltage are inversely proportional. It's not an exact way of doing it but if you divide the voltage by 10 you can multiply the amperage by 10 and get close. So, 120v / 10= 12v so 5a x 10 would be approximately 50amps. There are some other calculations that go into it but that'll give you an idea of where you are.
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creeky
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# Posted: 9 Jun 2015 08:12pm
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5 amps at 110 is 550 watts
5 amps at 12 is 60 watts
you usually see it expressed as w = a x v
watts = amps times voltage
I like to think of it as amps is the size of the pipe and volts is the pressure. so you can move the water you need (watts) through a thin pipe (low amps) with high pressure (high voltage)
or a big pipe (high amps) and low pressure (low voltage).
usually when bad things happen, it's when you try to run high amps through small pipes.
but in a sense, ya. an amp is just an amp. a symbol that denotes amperage (or the amount of water in the pipe).
and that's why electricity is so much fun 
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Bzzzzzt
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# Posted: 9 Jun 2015 08:16pm
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Sorry Creeky, but as an electrician I have to point out (because I'm OCD like that) there is no 110V. It's 120V. 5 amps at 120V is 600 watts. LOL
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Wilbour
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# Posted: 9 Jun 2015 10:19pm
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Quoting: Bzzzzzt Sorry Creeky, but as an electrician I have to point out (because I'm OCD like that) there is no 110V. It's 120V.
Interesting. Wikipedia says although it may have historically been 110 it's actually 120 but refered to as 110.
That's messed up on purpose!
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groingo
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# Posted: 9 Jun 2015 11:25pm
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Now I'l inject some further, my Killawatt says I'm pulling 124 volts....is it any wonder this stuff gives me headaches and even moreso when I come from both sides of the family which were radio technicians and electricians and an uncle that was an electrical engineer but somehow I just never got the Gene, although I can make things blow up which must be worth something?
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cman47c
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# Posted: 10 Jun 2015 08:15am
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For wire sizing, 5 amps is 5 amps no matter what the voltage or load is that it is calculated from. So 5 amps in a 120 VAC circuit is the same as 5 amps in a 12 VDC circuit as far as the wire sizing is concerned.
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creeky
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# Posted: 10 Jun 2015 09:25am
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thanks bzzzzt. Wilbour. I too am OCD. And do enjoy a good quibble.
I often see 110, 115 and more rarely 120 mentioned as a general guide.
Groingo. AC, at my place, is 114. That's what my inverter outputs according to my EM100 (the cheaper killawatt) anyway.
And, while we're quibbling: it's not a 12v system. It's 12.7 (or 12.8 if your using the new lithium batteries). Well, except my batteries are charging right now and they're at (wait let me open the web page) 13.97 in bulk charge mode. Heading for 14.5 (absorb).
ah. a quibble with my morning cup of coffee. sunshine on my panels. it's a good life.
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groingo
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# Posted: 10 Jun 2015 10:19am
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Creeky:
Ya got Lithium on the brain, or something odd growing in the garden, you know the stuff the rabbits been eating making then run backwards and bark like a dog!
I notice yesterday a neighbor had put up a sizeable solar system, looks like at least 3 to 5000 watter freestanding, gonna have to take a peek....yes I said take a peek, not a pee!
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Cowracer
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# Posted: 10 Jun 2015 03:34pm
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110 volts is a 'nominal' rating. Kinda like saying Honda saying their ATV is a 500cc when the engine size is really 475cc.
Any voltage between 100 and 127 is acceptable in the US. That is the RMS rating. Actual peak-to-peak voltage is actually around 155 volts. RMS voltage is roughly equivalent to the average voltage if it was converted from a sine wave to pulsating DC. (full wave rectified).
As far as the OP's question. Amps is amps regardless of voltage. The only issue that crops up is insulation. All wires (except a very few specialty wires that the general public usually cant get) are rated to 600volt anyway.
For the record, I call generally call it 110, but 115 and 120 will slip out occasionally.
Tim
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Bzzzzzt
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# Posted: 10 Jun 2015 10:07pm - Edited by: Bzzzzzt
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Cowracer is correct about "nominal" ratings. As a general rule in Arkansas and Missouri (Where I have worked the most) the power runs approximately 118-125V for residential customers.
Some appliances are rated for 115 volts but I have never heard anyone ever call the power feeding it 115 volts. Always 120 or 110.
I have heard that the difference between 110 and 120 is that originally power ran on 50hz and they discovered that a small shock would kill people easily because it was too close to the cycles of your heart so they upped it to 60hz which in turn raised the voltage from 110 to 120. I have never seen any proof of that claim but have heard it from multiple, unverifiable sources.
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bldginsp
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# Posted: 10 Jun 2015 10:56pm - Edited by: bldginsp
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Voltage varies due to numerous factors, but all equipment will operate just fine within a range of voltages. If voltage gets much below 110 or much above 120 (or below 220 or above 240) the equipment can begin to be strained. Manufacturers will list their appliance as 115, 120, 220, 240 or whatever, meaning that's what it's designed for in the development laboratory (or someone's garage) but it will work just fine within the normal range of voltages encountered in the field. Voltage drop is the most common problem, usually resulting from undersized supply wiring over too long a distance (like when I ran my saw on the end of 3 #12 gauge 100 foot extension cords. That was dumb).
Amperage is just a rate of flow, but is not indicative of the power (watts) available because that varies with the pressure (voltage) behind the amperage. The water pipe analogy works reasonably well to explain it, where voltage is pressure, amperage is rate of flow, and wattage is work actually done. Picture water wheels driven by water squirted at them. One has a very thin stream of water at very high pressure, the other has a very thick stream at very low pressure. The two wheels turn at the same speed, doing the same work.
Volts x amps = watts
1000 x 5 = 5000
5 x 1000 = 5000
But water pipe dynamics differ from electrical behavior in one critical respect. Turn up the water pressure and the rate of flow increases. But turn up the voltage and the amperage does not increase. But the wattage does.
My good friend Bob says,"All I know about electricity is that if you goof it hurts." Bob's a great framer but I'll hire someone else to pull wire.
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bldginsp
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# Posted: 11 Jun 2015 12:09am - Edited by: bldginsp
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"Is amperage the same regardless of voltage" is not really the best question, I think. No common household electrical system is designed to intentionally alter or vary the voltage. Yes it varies a bit according to numerous factors, and yes, while those factors vary the amperage remains the same in a given piece of operating equipment.
Amperage is the rate of flow allowed by the piece of equipment that has electrical potential applied to it. All equipment introduces resistance to the flow of electricity in the process of doing what it does. The equipment prevents the electricity from doing what it has the potential to do, which is flow unimpeded, and allows a limited rate of flow through. In the process it uses the potential of the limited amount that passes through to do something (turn a motor, heat something, make light, etc.) At the other end of the light bulb, the electricity still has the same amperage (rate of flow) but far less voltage (power or potential to do something) because the light bulb used it up (wattage).
People say that an appliance "pulls" a certain amperage but actually it is resisting the force imposed on it, while allowing a certain amount thru, only enough to do the work.
Hope I haven't confused you, and I know I repeated a lot of what was said above. I had to read numerous explanations of this stuff from persons more experienced than myself before, pardon the expression, the light came on enough for me to use my limited potential.
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MtnDon
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# Posted: 12 Jun 2015 01:38pm
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60 HZ is more efficient than 50 Hz for transmission of power as well as transforming one voltage to another.
In Europe the driving force after WW2 was a company called AEG. They chose to use 50 Hz as it fit the metric system better. Prior to WW2 they used 110 VAC; post WW2 they chose to increase efficiency by increasing voltage to 220 VAC. Companies in the USA wanted to raise voltage and efficiency also. But because we had a head start in the number of electrical appliances like refrigerators it was deemed too costly to change the mains voltage. Not to mention that much of the EU ower system was obliterated during the war so they could start over more readily. We compromised by using a double system (110/220, 120/240).
Some of my older power tools have 115 volt AC ratings.
Way back when, Edison used 110 VDC and Tesla used 240 VAC.
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ILFE
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# Posted: 5 Jul 2015 04:07pm
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Quoting: Bzzzzzt Sorry Creeky, but as an electrician I have to point out (because I'm OCD like that) there is no 110V. It's 120V.
In the US, yes. Here in Cambodia, and elsewhere in Southeast Asia, for some odd reason, they have voltage transformers that convert 230vac, down to 110vac OR 100vac, from the same voltage converter. Not really sure why they have them set up like that, here. But, it is quite commonplace.
Oh, you can ignore the "High Quality Product" line. They are junk.
Vietnamese Power Converter
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