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. In a SAW power source with an engine-driven generator, what does a drooping volt-ampere characteristic primarily protect against?

    Answer: Electrode stubbing and arc instability under varying load

    A drooping (constant-current) characteristic limits current surges when the arc length shortens, preventing electrode stubbing and maintaining arc stability.

  2. When tuning a diesel engine driving a SAW generator for cold-weather starts, which adjustment is most important?

    Answer: Verifying glow plug function and fuel viscosity rating

    Cold diesel starts rely on adequate glow plug heat and low-viscosity fuel to ensure proper atomization and ignition at low temperatures.

  3. A SAW tractor's engine-driven wire feeder loses consistent wire feed speed as engine RPM fluctuates. The most likely cause is:

    Answer: An unstable governor on the engine

    Wire feed speed in engine-driven SAW systems is often tied to engine RPM; governor instability causes RPM swings that directly translate to inconsistent wire feed.

  4. During SAW, the open-circuit voltage (OCV) of an engine-driven power source is measured at 75V. What does this indicate about engine performance?

    Answer: The engine is running at or near rated RPM producing full excitation

    OCV at or above specified levels confirms the engine is spinning the generator at rated speed, ensuring full magnetic excitation and voltage output.

  5. An engine-driven SAW unit shows excessive black smoke under welding load. The most appropriate corrective action is:

    Answer: Service the fuel injection system and air filter

    Black smoke indicates rich combustion caused by insufficient air or poor fuel atomization; servicing the air filter and injectors restores proper air-fuel ratio.

  6. What is the purpose of the isochronous governor in an engine driving a SAW welding generator?

    Answer: To maintain constant engine RPM regardless of electrical load changes

    An isochronous governor holds engine speed constant across load variations, ensuring stable welding output voltage and consistent arc performance.

  7. In SAW equipment, what effect does running the engine at below-rated RPM have on welding arc performance?

    Answer: It lowers OCV and may cause arc instability or failure to strike

    Below-rated RPM reduces generator output, lowering OCV and available current, which makes arc starting difficult and causes unstable arc behavior.