Which type of power source is described as having a drooping volt-amp curve?

Which type of power source is described as having a drooping volt-amp curve?

• A. Constant Current machine
• B. Constant Voltage machine
• C. AC transformer
• D. DC inverter

Answer: (A)

Drooping volt-amp curve points to a power source that regulates current rather than voltage. In a constant current welding power supply, the system holds the current nearly steady, and as the arc requires more current or as the load changes, the voltage drops to maintain that current. That downward tilt in the V-A relationship is the hallmark of current-controlled operation: increasing current doesn't come with a proportional increase in voltage, it comes with a reduction in voltage to keep the current stable. In contrast, a constant voltage source aims to keep the arc voltage fixed, so the current varies with the load and the V-A curve isn’t dominated by a downward slope. An AC transformer simply provides a set voltage (and any droop depends on regulation, not on actively limiting current). A DC inverter can operate in either constant current or constant voltage mode, so its V-A behavior isn’t defined as a drooping curve by default. So the drooping volt-amp characteristic best describes a constant current power source.

Drooping volt-amp curve points to a power source that regulates current rather than voltage. In a constant current welding power supply, the system holds the current nearly steady, and as the arc requires more current or as the load changes, the voltage drops to maintain that current. That downward tilt in the V-A relationship is the hallmark of current-controlled operation: increasing current doesn't come with a proportional increase in voltage, it comes with a reduction in voltage to keep the current stable.

In contrast, a constant voltage source aims to keep the arc voltage fixed, so the current varies with the load and the V-A curve isn’t dominated by a downward slope. An AC transformer simply provides a set voltage (and any droop depends on regulation, not on actively limiting current). A DC inverter can operate in either constant current or constant voltage mode, so its V-A behavior isn’t defined as a drooping curve by default.

So the drooping volt-amp characteristic best describes a constant current power source.