Electrical Final 2A Exam Questions And Answers

According to the power triangle, the apparent power is _____. - ANS greater than true power Any exposed live parts must be guarded if they are operating at _____. - ANS 50v or more between terminals. In a split-phase motor, how much greater is the starting current when compared to the full-load current? - ANS 6 to 8 times The capacitor-start motor is the single-phase motor type that has the _____. - ANS highest starting torque For a constant-torque load, the horsepower increases and decreases _____. - ANS in direct proportion to the speed The primary method of varying the speed on a DC shunt motor is to adjust the voltage and current on the field winding or the _____. - ANS armature According to NEMA definitions, which of the following is a type of open motor? - ANS Weather-Protected The value indicated in rpm on the nameplate is the _____. - ANS rated full-load speed The power factor of an induction motor at no-load conditions can be as low as: - ANS 15% Which of the following motors provides constant speed from no-load conditions to full-load conditions? - ANS Synchronous The most common service factor appearing on a motor's nameplate is _____. - ANS 1.15 Several motors are permitted to be supplied by a single branch circuit as long as each motor is no larger than _____. - ANS 1hp Which of the following are most likely to use dynamic braking? - ANS Forklifts The stationary magnet of a DC motor is represented by the _____. - ANS Field poles Which of the following motors is the best installation choice for an application requiring adjustable speeds? - ANS DC The speed of a three-phase squirrel cage induction motor is controlled by the frequency of the applied voltage and _____. - ANS the number of poles DC injection braking is used on _____. - ANS the stationary windings of AC motors The NEC® requires motor disconnecting means be _____. - ANS within sight of the controller location A polyphase synchronous motor has three stator windings that are _____. - ANS 120 degrees apart A three-phase induction motor may have _____. - ANS 2 poles The terminals of a motor can be identified using a battery and a(n) _____. - ANS voltmeter Which motor should be used for applications that require frequent starts without overheating the motor? - ANS would rotor induction motor According to NEMA definitions, which of the following is a type of totally enclosed motor? - ANS Water-cooled In a DC series motor, how much of its full-load torque is developed at starting? - ANS 500% A delta-connected motor has _____. - ANS 9 Leads For a given number of poles, which of the following determines the speed of an AC motor? - ANS Frequency Which of the following motors is used where the required starting torque is high and speed control is desirable? - ANS Compound The synchronous speed at which a four-pole, 60Hz induction motor operates is _____. - ANS 1,800 rpm A typical constant-torque load would be a(n) _____. - ANS conveyor Horsepower is used to rate the _____. - ANS output capacity of a motor A medium-size motor has a frame number of 284T. The D dimension of this motor is - ANS 7" Which of the following is true regarding the storage and handling of lighting fixtures? - ANS Wear gloves when handling fixtures to protect finished surfaces Which of the following materials absorbs the most light? - ANS Dark red-glazed bricks The type of high-intensity discharge (HID) lamp that has excellent color rendition is the - ANS metal halide lamp The junction box and recessed lighting fixture should be separated by a minimum distance of _____. - ANS 1' Which of the following are often used in conjunction with time clocks to turn off lighting when it is no longer needed? - ANS Photosensors A type of system that can be used to control both lighting and HVAC equipment is a(n) _____. - ANS EMS Energy legislation promotes the replacement of full-wattage fluorescent lamps with higherefficiency types, such as _____. - ANS T-5s Unless it is protected or is a low-voltage type of track, track lighting on a wall must be installed at least _____. - ANS 5' above the floor Which type of ballast has the highest efficiency? - ANS Electronic instant-start Which color temperature produces a balance between warmth and coolness? - ANS 3,500K Ultrasonic occupancy sensors are triggered by _____. - ANS motion Which of the following will shorten the life of a filament in an incandescent lamp? - ANS Operating at warmer temperatures