SAW Electrical Systems & Wiring 2 — Questions and Answers
Question 1: What is the purpose of the inductance control on a SAW power source?
- To adjust the open-circuit voltage
- To control the rate of current rise and arc stability (Correct answer)
- To set the wire feed speed
- To regulate the flux hopper temperature
Correct answer: To control the rate of current rise and arc stability
Inductance controls the rate of current rise during short circuits, smoothing arc behavior and reducing spatter in SAW operations.
Question 2: Which type of electrical connection produces deeper penetration in SAW: electrode positive (DCEP) or electrode negative (DCEN)?
- DCEN produces deeper penetration
- DCEP produces deeper penetration (Correct answer)
- Both produce identical penetration
- AC always produces deeper penetration than either DC polarity
Correct answer: DCEP produces deeper penetration
DCEP (reverse polarity) drives more heat into the base metal, resulting in deeper weld penetration compared to DCEN.
Question 3: A SAW system shows erratic wire feeding and unstable voltage readings. The most likely electrical cause is:
- Excessive flux depth
- Poor contact tip-to-work distance
- Worn or contaminated contact tip causing poor electrical contact (Correct answer)
- Incorrect travel speed
Correct answer: Worn or contaminated contact tip causing poor electrical contact
A worn or contaminated contact tip creates inconsistent current transfer to the electrode wire, causing erratic arc behavior.
Question 4: In a SAW multi-wire system, the trailing electrode is typically connected to:
- DCEP to maximize deposition rate
- AC to reduce arc blow interference between electrodes (Correct answer)
- DCEN to increase travel speed
- The same polarity as the lead electrode
Correct answer: AC to reduce arc blow interference between electrodes
The trailing electrode in multi-wire SAW is typically on AC to minimize magnetic arc blow caused by interaction between DC magnetic fields.
Question 5: What does the term 'arc voltage' specifically measure in a SAW electrical circuit?
- The voltage at the power source terminals
- The voltage drop across the welding arc between electrode tip and weld pool (Correct answer)
- The open-circuit voltage before striking the arc
- The voltage across the contact tube
Correct answer: The voltage drop across the welding arc between electrode tip and weld pool
Arc voltage is the actual voltage measured across the arc gap between the electrode tip and the molten weld pool.
Question 6: When using a constant current (CC) power source for SAW, what controls the wire feed speed?
- The power source output setting directly
- A separate voltage-sensing wire feeder that adjusts speed to maintain arc length (Correct answer)
- The travel speed of the welding head
- The flux layer depth
Correct answer: A separate voltage-sensing wire feeder that adjusts speed to maintain arc length
With a CC source, a voltage-sensing wire feeder automatically adjusts feed speed to maintain a consistent arc voltage and arc length.
Question 7: What is the function of the work clamp (ground connection) in a SAW electrical circuit?
- It provides a path for flux current return
- It completes the welding circuit and carries the full welding current back to the power source (Correct answer)
- It measures the arc voltage
- It controls the wire feed speed
Correct answer: It completes the welding circuit and carries the full welding current back to the power source
The work clamp completes the welding circuit, allowing full welding current to return from the workpiece to the power source.
SAW Electrical Systems & Wiring 2
What is the purpose of the inductance control on a SAW power source?