When is a voltage sensing wire feeder used?

When is a voltage sensing wire feeder used?

• A. with a constant current power source
• B. with a constant voltage power source
• C. with AC power only
• D. with no power source

Answer: (A)

Voltage-sensing wire feeders rely on arc-voltage feedback to regulate how fast the wire is fed. They adjust the feed speed in response to changes in the arc voltage so the arc length remains relatively stable. This feedback works best when the welding power source is operating in constant-current mode, because the current is held steady and any changes in arc length show up as voltage changes that the feeder can respond to. If the source were constant-voltage, the arc voltage stays near the set level, leaving little meaningful voltage variation for the feeder to react to, so the feedback loop wouldn’t regulate the arc effectively. AC power or no power wouldn’t provide the stable conditions needed for this voltage-based regulation to function.

Voltage-sensing wire feeders rely on arc-voltage feedback to regulate how fast the wire is fed. They adjust the feed speed in response to changes in the arc voltage so the arc length remains relatively stable. This feedback works best when the welding power source is operating in constant-current mode, because the current is held steady and any changes in arc length show up as voltage changes that the feeder can respond to. If the source were constant-voltage, the arc voltage stays near the set level, leaving little meaningful voltage variation for the feeder to react to, so the feedback loop wouldn’t regulate the arc effectively. AC power or no power wouldn’t provide the stable conditions needed for this voltage-based regulation to function.