Hi Jeff, a #10 AWG 30 amp 220V cord should be more than enough to cover the minimal voltage drop you would see over 30ft..as the distance increase's the voltage drops..the wattage or load stays the same so the current goes up..thats why we increase the conductor size..its a triangle.. A squared + B squared = C squaredI want more reach with my welder. It only has about a 12 ft cord and I'd like to add a 25 or 30 ft extension cord to it. Will a 30 amp cord be enough for welding on setting 1 or 2 of 5? The welder is a Hobart 220V.
I think the pythagorean theoram had to do with the sides of a right triangle.that would be the one..basic electricity
HeHe..Mr Ohm must be working on a different site than me.. i use Mr Fluke for my digital..Mr. Ohm used his digital multimeter to measure volts, current, and resistance.
:confused0006:Remember to alway unwind the lead DO NOT COIL the lead up even on short runs
How so? The cord is a resistor, and it causes the voltage drop to the welder. The current cannot go up with more resistance in the circuit. Voltage drops, current drops (at the same setting) and wattage drops as a result. Watts is voltage times amps.as the distance increase's the voltage drops..the wattage or load stays the same so the current goes up..
The reason it happens on a motor is due to back-EMF. With lower input voltage, the motor turns slower. As it turns slower, the back EMF decreases and you get more current through the windings. A welder does not act like a generator, so no back-EMF is produced. If you increase cord resistance, you decrease current and increase voltage drop (ohm's law). So wattage decreases at the welder with the same setting. If you want the same wattage, you have to turn the welder up, so current increases.Whether the current increases as the voltage decreases depends on the load you are running. With an electric motor that will happen. Not sure about a welder - I think it will when you crank up the output current as reaction to the drop in voltage. Think constant power to get a job done. On the other hand most welders are described as "constant current" machines.
But I am far from an expert on how input voltage affects welding machines. Or for that matter how it affects transformer machines vs. inverter machines.
The key phase being..LOAD stays the same..same amount of output from the welder..input current will rise.How so? The cord is a resistor, and it causes the voltage drop to the welder. The current cannot go up with more resistance in the circuit. Voltage drops, current drops (at the same setting) and wattage drops as a result. Watts is voltage times amps.
That only applys to a DC motor..the only ways to change the speed of a AC motor is a change in the number of poles or frequency. thats why we have Variable Frequency drives for conveyors and large aerial coolers in plantsWith lower input voltage, the motor turns slower.