Practice Test Geeks(PC) Professional Electrical Contractor Practice Test
← All PC Flashcard Decks

Motors and Motor Controls Flashcards

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

Read the first 6 Motors and Motor Controls flashcards as text

  1. Which NEC article covers motors, motor circuits, and controllers?

    Answer: Article 430

    NEC Article 430 covers motors, motor circuits, and controllers including disconnecting means and overcurrent protection.

  2. What is the minimum ampacity required for branch circuit conductors supplying a single continuous-duty motor?

    Answer: 125% of motor FLA

    Per NEC 430.22, branch circuit conductors for a single motor must be sized at no less than 125% of the motor's full-load current.

  3. Which device provides both overload protection and short-circuit protection for a motor in a single assembly?

    Answer: Combination motor controller

    A combination motor controller integrates a disconnect means, overcurrent protection, and overload protection in one unit.

  4. Per NEC Table 430.52, what is the maximum inverse time circuit breaker rating for a Design B motor with an FLA of 40A?

    Answer: 100A

    For Design B motors, NEC Table 430.52 permits up to 250% of FLA for inverse time breakers: 40A × 2.5 = 100A.

  5. What is the primary purpose of a motor overload relay?

    Answer: To protect motor windings from damage due to overheating

    Motor overload relays monitor current over time and trip to prevent motor windings from overheating under sustained overload conditions.

  6. A motor has a nameplate FLA of 20A and a service factor of 1.15. What is the maximum overload protection rating per NEC 430.32?

    Answer: 26A (130%)

    Per NEC 430.32(A)(1), motors with a service factor of 1.15 or higher may use overload protection sized up to 130% of FLA: 20A × 1.30 = 26A.