Final answer:
A constant potential welding machine typically operates in a voltage range suitable for arc welding, generally between 20 to 100 volts, to maintain a stable arc and sufficient heat.
Step-by-step explanation:
The constant potential welding machine operates within a certain voltage range which depends on the specific type of machine and its application. Welding machines for industrial purposes must be capable of working with a wide range of materials and thicknesses, hence requiring a flexible voltage range. While the voltage ranges provided in the reference materials do not specifically state the range for a constant potential welding machine, typical welding voltages for arc welding, which is a common application for such machines, are usually between 20 to 100 volts. This allows for a stable arc and sufficient heat to melt the metal workpieces. It's important to note that while other forms of power transmission deals with much higher voltages, the voltages used in welding are lower and tailored for the safety and efficacy of the welding process.