Practice Test Geeks(SAW) Submerged Arc Welding Certification Practice Test
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Engine Performance & Tuning Flashcards

7 cards from real SAW practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Engine Performance & Tuning flashcards as text

  1. When re-tuning an engine-driven SAW unit after an altitude change from sea level to 5,000 feet, the operator should expect:

    Answer: Reduced engine power output requiring derating of the welding schedule

    At altitude, reduced air density decreases oxygen availability for combustion, lowering engine power output and requiring the welding schedule to be derated accordingly.

  2. In a SAW setup, the engine-driven generator produces AC current that is then rectified for DC welding. A fault in the rectifier bridge causes:

    Answer: Ripple in the DC output leading to arc instability and poor bead profile

    A faulty rectifier diode causes incomplete AC-to-DC conversion, introducing AC ripple into the welding output that destabilizes the arc and creates an uneven weld bead.

  3. What is the primary purpose of the mechanical governor droop setting on a SAW engine-driven unit?

    Answer: To allow slight RPM reduction under increasing load, improving governor stability

    Droop allows the governor to accept a small speed decrease as load increases, which prevents hunting and improves stability at the cost of perfect isochronous regulation.

  4. An engine-driven SAW unit is being stored for 3 months. Which engine preservation step is most important for preventing fuel system problems upon restart?

    Answer: Adding a fuel stabilizer and running the engine briefly to distribute it through the system

    Diesel and gasoline fuel degrades during storage; adding a stabilizer and circulating it prevents varnish deposits that clog injectors and carburetors.

  5. During SAW on thick plate at 900A, the engine-driven unit's engine temperature warning activates. The immediate action should be:

    Answer: Stop welding, allow the engine to idle and cool, then investigate the cooling system

    Overheating risks permanent engine damage; stopping the weld, idling to circulate coolant, and investigating the cause (coolant level, fan, thermostat) is the safe immediate response.

  6. A SAW engineer is selecting between a 60 Hz AC generator and a DC generator for a new engine-driven SAW installation. For single-wire SAW at high deposition rates, the advantage of DC is:

    Answer: Superior arc stability and control over penetration profile via polarity selection

    DC power provides a stable, smooth arc with directional control — DCEP for deeper penetration, DCEN for higher deposition — giving the operator greater process control than AC.

  7. What is the recommended approach when an engine-driven SAW unit requires simultaneous engine overhaul and generator rewinding?

    Answer: Decouple the generator from the engine and perform both overhauls simultaneously, then recouple and test OCV and welding output

    Decoupling allows concurrent overhaul of both components, minimizing downtime; recoupling followed by OCV and load testing confirms proper alignment and performance restoration.