Practice Test Geeks(EETC) Electrical Technician Certification Practice Test
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Electrical Equipment & Maintenance Flashcards

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

Read the first 7 Electrical Equipment & Maintenance flashcards as text

  1. What is the recommended maximum shaft voltage level on a VFD-driven motor before bearing damage becomes a concern?

    Answer: 500 mV peak

    Shaft voltages above approximately 500 mV peak can discharge through bearings, causing pitting and fluting damage known as electrical discharge machining (EDM).

  2. In a motor control center (MCC), what is the purpose of the stab assembly?

    Answer: Make electrical connection between the bucket and the vertical bus bar

    Stab assemblies are the plug-in connectors on MCC buckets that make contact with the vertical bus bars when the unit is inserted into the structure.

  3. An overload relay is tripping on a motor that is lightly loaded. The MOST likely cause is:

    Answer: Incorrect overload relay heater elements installed for the motor FLA

    Heater elements sized for higher FLA will not trip under normal load, but elements sized too small will trip the relay even under light load conditions.

  4. What does the term 'dielectric withstand' (hi-pot) testing verify in electrical equipment?

    Answer: The ability of insulation to withstand overvoltage without breakdown

    Hi-pot testing applies elevated voltage to insulation to verify it will not break down under transient overvoltages encountered in service.

  5. When performing contact resistance testing on a circuit breaker, results significantly higher than manufacturer specs indicate:

    Answer: Pitted, burned, or corroded contacts that increase resistance and heating

    High contact resistance causes excessive I²R heating under load, which can cause contact failure, welding, or nuisance tripping.

  6. The synchronous speed of a 4-pole induction motor operating on a 60 Hz system is:

    Answer: 1800 RPM

    Synchronous speed = (120 × frequency) / poles = (120 × 60) / 4 = 1800 RPM; actual rotor speed is slightly less due to slip.

  7. What maintenance action is required when the insulating oil in a transformer tests at a dielectric breakdown voltage below 26 kV (per ASTM D877)?

    Answer: Filter, process, or replace the oil to restore dielectric strength

    Oil below 26 kV dielectric strength per ASTM D877 must be reconditioned through filtration/drying or replaced to prevent insulation failure.