430

a. IV only

Conductors for a motor used in a short-time, intermittent, periodic, or varying duty application shall have an ampacity of not less than the percentages of the motor nameplate current ratings shown in Table ___. I. 430.148 II. 430.150 III. 430.7(B) IV. 430.22(E) Select one: a. IV only b. III or IV only c. I or II only d. II only e. I only

c. 62.7

A feeder supplying two continuous duty, induction type, Design B, 208-volt, three-phase motors (one 10 hp and one 7 1/ 2 hp) shall have a minimum ampacity of ___ amperes. Select one: a. 38.5 b. 68.75 c. 62.7 d. 55

a. 4

What size THHN copper transformer secondary conductors will be required to feed a 3-phase, 30 hp, 480-volt motor load? The secondary conductors terminate at a fusible disconnect with 70 amp fuses. The delta - delta transformer primary is supplied by a 12,470-volt circuit protected with 10 amp fuses. Select one: a. 4 b. 10 c. 3 d. 8 e. 6

c. 3

Where a motor branch circuit is supplied from a corner-grounded delta system and fuses are used for motor overload protection, the NEC® requires a minimum of ___ fuses. Select one: a. 0 b. 1 c. 3 d. 2

d. 15 amperes at 125 volts

Where a motor is connected to a branch circuit by means of an attachment plug and receptacle and individual overload protection is omitted, the rating of the attachment plug and receptacle shall not exceed ___ or 250 volts. Select one: a. 15 amperes at 110 volts b. 25 amperes at 120 volts c. 20 amperes at 115 volts d. 15 amperes at 125 volts

c. 500

Where the motor control circuit transformer rated primary current is less than 2 amperes, an overcurrent device rated or set at not more than ___% of the rated primary current shall be permitted in the primary circuit. Select one: a. 167 b. 125 c. 500 d. 250 e. 300

b. both the motor and controller

In general, a motor disconnecting means must disconnect ___. Select one: a. only the control circuit b. both the motor and controller c. only the motor d. only the controller

e. 115

The disconnecting means for motor circuits rated 600 volts, nominal, or less, shall have an ampacity rating of at least ___% of the FLC rating of the motor. Select one: a. 100 b. 135 c. 125 d. 80 e. 115

b. 23.4 amps

The overload protection you have selected for the motor detailed below is not sufficient to start the motor and it trips. Determine the maximum size overload protection permitted. Motor Information: 480-volt, 3-phase, 15 hp, continuous duty * Design B * temperature rise - 40ºC * service factor - 1.12 * actual nameplate rating - 18 amps Select one: a. 22.5 amps b. 23.4 amps c. 25.2 amps d. 20.7 amps

d. 200

Synchronous motors of the low-torque, low-speed type, such as are used to drive reciprocating compressors, pumps, and so forth, that start unloaded, do not require a fuse rating or circuit-breaker setting in excess of ___ percent of full-load current. Select one: a. 400 b. 150 c. 250 d. 200

a. highest

Dual-voltage motors that have a different locked-rotor kVA per horsepower on the two voltages shall be marked with the code letter for the voltage giving the ___ locked-rotor kVA per horsepower. Select one: a. highest b. lowest c. average d. normal

b. 6

Two or more motors may be connected to a single 120-volt, 20-ampere branch circuit if each motor is rated at 1 hp or less, and the full-load current rating of each motor does not exceed ___ amps. Select one: a. 2 b. 6 c. 4 d. 5

c. 3

What is the minimum number of overload units such as heaters, trip coils, or thermal cutouts allowed for a three-phase AC motor's protection? Select one: a. 2 b. 1 c. 3 d. none of these

a. 45 amp

A 14 AWG THHN copper conductor is used between a motor starter and a remote start/stop station. What is the maximum size circuit breaker permitted for the motor short-circuit ground-fault protection that will also protect the 14 AWG conductor? Select one: a. 45 amp b. 60 amp c. 15 amp d. 10 amp

c. 6P

A motor controller enclosure that is subject to occasional prolonged submersion shall be type ___. Select one: a. 3S b. 12 c. 6P d. 4X

b. 3 AWG

Determine the minimum size THW copper branch-circuit conductors the NEC® requires to feed a 3-phase, continuous duty motor that draws 70 amps per phase. Assume terminations are rated at 75ºC. Select one: a. 4 AWG b. 3 AWG c. 1 AWG d. 2 AWG

a. 1 AWG

What is the minimum size THWN copper conductors required to serve a continuous duty, 25 hp, 208 volt, 3-phase motor? The motor is on the end of a conduit run that contains only three wires, at an ambient temperature of 50 deg. C. Select one: a. 1 AWG b. 2 AWG c. 3 AWG d. 6 AWG

c. 4.0 - 4.49

A code letter D is marked on a motor nameplate. What is its locked-rotor kVA per horsepower? Select one: a. 3.15 - 3.54 b. 0 - 3.14 c. 4.0 - 4.49 d. 3.55 - 3.99

b. continuous duty

Any motor application shall be considered at ___ unless the nature of the apparatus it drives is such that the motor will not operate continuously with load under any condition of use. Select one: a. short-time duty b. continuous duty c. periodic duty d. varying duty

a. at standstill

Torque motors are rated for operation ___. Select one: a. at standstill b. at full torque c. with code letter d. at F.L.C.

b. the locked-rotor current

Each controller shall be capable of starting and stopping the motor it controls and shall be capable of interrupting ___ of the motor. Select one: a. 125% of the full-load current b. the locked-rotor current c. the table FLA current rating d. the nameplate FLA current rating

c. breaker be able to be locked in the open position

If a circuit breaker serves as the controller for a motor, and the motor is not in sight of the breaker, the NEC® requires the ___. Select one: a. breaker to have an interrupting rating of 25,000 A b. motor to be Code letter "E" c. breaker be able to be locked in the open position d. motor to be less than 2 hp

b. knife switch

Which one of the devices listed is NOT permitted to be used to provide branch-circuit and short-circuit protection for motors? Select one: a. nonadjustable circuit breaker b. knife switch c. non-time delay fuses d. thermal protective devices

d. 20.7 amps

Determine the minimum size overload protection required for a 480-volt, 3-phase, 15 hp, continuous duty motor given the following information. * Design B * temperature rise - 40ºC * service factor - 1.12 * actual nameplate rating - 18 amps Select one: a. 18 amps b. 22.5 amps c. 23.4 amps d. 20.7 amps

b. ungrounded

Where the motor controller also serves as a disconnecting means, it shall open all ___ conductors to the motor. Select one: a. grounded b. ungrounded c. grounding d. neutral

a. Barriers

___ shall be placed in all service-entrance motor control centers to isolate service busbars and terminals from the remainder of the motor control center. Select one: a. Barriers b. Markers c. Switches d. Isolators e. Conductors

b. not be required

A motor is installed as part of a factory-wired piece of equipment. It is required to be grounded, and no additional connections are required at the motor terminal housing during the equipment installation. A separate means for motor grounding at the motor terminal housing shall ___. Select one: a. be sized to the wire b. not be required c. be required d. be bonded to the equipment

d. 1/ 3

An attachment plug and receptacle may be permitted to serve as a motor controller if the motor is portable and has a maximum rating of ___ hp. Select one: a. 1/ 4 b. 1/ 2 c. 2 d. 1/ 3 e. 1/ 8

b. 125%

Branch-circuit conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than ___ of the motor's full-load current rating as determined by 430.6(A)(1). Select one: a. 150% b. 125% c. 50% d. 190% e. 58%

b. 125

Circuit conductors supplying power conversion equipment included as part of an adjustable-speed drive system shall have an ampacity not less than ___ percent of the rated input current to the power conversion equipment. Select one: a. 100 b. 125 c. 80 d. 175

b. 125

Continuous duty motors with a marked service factor not less than 1.15 shall have the minimum running overload protection sized at ___ percent of the nameplate rating of the motor. Select one: a. 140 b. 125 c. 115 d. 130

c. 400

For a nonautomatically started motor, the overload protection shall be permitted to be shunted or cut out of the circuit during the starting period of the motor if the device by which the overload protection is shunted or cut out cannot be left in the starting position and if fuses or inverse time circuit breakers rated or set at not over ___ percent of the full-load current of the motor are located in the circuit so as to be operative during the starting period of the motor. Select one: a. 115 b. 140 c. 400 d. 125 e. 130

c. NEC® Tables

For general motor application, the fuse size for the motor branch circuit must be determined from ___. Select one: a. Factory Mutual b. motor nameplate current c. NEC® Tables d. NEMA standards

b. 7

Screw-type pressure terminals used with 14 AWG or smaller copper conductors in motor controllers shall be torqued to a minimum of ___ pound-inches. Select one: a. 12 b. 7 c. 10 d. 20

d. the proper connection

Terminals of motors and controllers shall be suitably marked or colored where necessary to indicate ___. Select one: a. horsepower ratings b. correct rotation c. torque requirements d. the proper connection