What are the Adavantages of High Amperage?

Pharrahnox

What are the advantages of having high amperage? By the way, I'm rather new to electronics.

I know that having high-voltage reduces the energy loss through the wire, and you don't need as thick a wire. But I cannot find the advantages of high amperage on the internet. This may be due to my bad wording of the question, or due to my lack of knowledge on the subject, however I still would like to know.

Thanks for any help, in advance.

phinds

One example of where it is advantageous (a necessity really) to have high current (and very low voltage) is in electronic welding.

It would be very dangerous to provide welding-level power using very much voltage, so typically (as I recall) welding is done with 3 volts and hundreds of amps.

Drakkith

High currents are usually needed to provide high amounts of power to something. I don't really know if there's an "advantage" or not. I always thought of current as simply the consequence of your voltage and resistance.

Pharrahnox

Thanks for the fast replies.

Why is it dangerous to have high voltage in electronic welding? Is it so that the arc cannot travel far, or doesn't want to go through your body?

marcusl

It's not so much a safety thing (welding is already plenty dangerous) but a property of the welding arc, which has very low resistance. Producing high power to melt the metal with a low resistance naturally requires high current and low voltage.

Drakkith

I believe a higher voltage would increase the current even further.

marcusl

Yes but there is an optimal current for each welding job. Factors include the type of metal to be welded and its thickness, the type of filler metal, the thickness of the filler rod, and the weld process used (e.g., TIG). Increase the current too far for the conditions and you produce lousy welds and/or melt too much of the metal. 50 - 200A are commonly used.

Studiot

The magnetic effect is proportional to the current, not the voltage so any application that depends upon the magnetic effect such as electric motors and induction cookers and furnaces are controlled by current.

Electrochemical processes are current controlled so not only resistance welding but aluminium smelting, electroplating, battery charging etc.

Pharrahnox

Oh, I didn't know that the magnetic effect relied on amperage. I thought it was just a higher charge in general, but this helps, as I have been interested in increasing the power of my solenoid.

mfb

If you want to generate magnetic fields with coils, current (and geometry) is the important quantity. Voltage is just a nasty by-product required to power the coils, unless they are superconducting.
As an example, the LHC uses superconducting coils with some kiloampere current in the cables. They produce a magnetic field of up to ~5T (design value is something like 9T).

Caio Ferrari

For transmitting energy, high amperages are a very bad idea due to joule effect.

The advantage is generating a large amount of magnetic filed around it.

Andrew Mason

The main reason for higher current is the need for lower voltage. For a vehicle even 100 volts would pose a significant safety hazard. The Prius uses just under 300 volts but only for the drive train functions which are heavily protected - the rest of the car uses 12 volts. If Henry Ford had used 100 volts in the Model T there would have been a lot of dead Ford owners who would not be coming back to buy another one.

AM

jartsa

If the advantage of high voltage is that no thick wires are needed, then the advantage of high amperage should be that no thick electric insulation is needed.

Pharrahnox

Why is high voltage more dangerous than high amperage?

Andrew Mason

It is not. It's the amps that kills you. But in order to get high current to pass through you, you need high voltage. It is just Ohm's law. I = V/R.

Study Ohm's law first and you will understand how voltage and current are related.

AM

phinds

While it is true that low voltage/high amperage wires require less insulation than the other way round, that is irrelevant to the reasons for USING them --- it's just a side effect.

phinds

If you have a 10volt potential that is capable of delivering 1,000,000 amps, it will not hurt you at all to grab the leads, because low voltage won't actually USE much at all of that current capabiltiy on your high-resistance body.

If you have a 10,000 volt potential that is capable of delivering a tenth of an amp and you grab the leads, it will most likely kill you because the high voltage will push enough current through your body to do so.