Article 430

Lakukan tugas rumah & ujian kamu dengan baik sekarang menggunakan Quizwiz!

A separate overload device used to protect continuous-duty motors rated more than 1 hp shall be selected to trip at no more than _____ percent of the motor nameplate full-load current rating if marked with a service factor of 1. 15 or greater.

125

Overcurrent protection for motor control circuits shall not exceed _____ percent if the conductor is based on Table 310. 15(B)(17) and does not extend beyond the motor control equipment enclosure.

400

Motor control circuit transformers, with a primary current rating of less than 2A, can have the primary protection device set at no more than _____ percent of the rated primary current rating.

500

A motor disconnecting means can be a listed _____.

any of these

The motor disconnecting means for a motor shall _____ whether it is in the open (off) or closed (on) position.

plainly indicate

The motor branch-circuit short-circuit and ground-fault protective device shall be capable of carrying the _____ current of the motor.

starting

Conductors supplying several motors shall not be sized smaller than _____ percent of the full-load current rating of the highest rated motor, plus the sum of the full-load current ratings of all other motors in the group, plus the ampacity of other loads.

125

Branch-circuit conductors supplying a single continuous-duty motor shall have an ampacity not less than _____ rating.

125 percent of the motor's full-load current rating as determined by 430.6(A)(1)

Feeder tap conductors supplying motor circuits, with an ampacity at least one-third that of the feeder, shall not exceed _____ ft. in length.

25

The maximum rating or setting of an inverse time breaker used as the motor branch-circuit short-circuit and ground-fault protective device for a single-phase motor is _____ percent of the full-load current given in Table 430.248.

250

Motor control circuit conductors that extend beyond the motor control equipment enclosure shall have short-circuit and ground-fault protection sized not greater than _____ percent of the value specified in Table 310. 15(B)(16) for 60º C conductors.

300

Torque requirements for motor control circuit device terminals shall be a minimum of _____ lb-in. (unless otherwise identified) for screw-type pressure terminals used for 14 AWG and smaller copper conductors.

7

For stationary motors of 2 hp or less and 300V or less on ac circuits, the controller can be an ac-rated only general-use snap switch where the motor full-load current rating is not more than _____ percent of the rating of the switch.

80

Where more than one motor disconnecting means is provided in the same motor branch circuit, at least one of the disconnecting means shall be readily accessible.

True

Overload devices are intended to protect motors, motor control apparatus, and motor branch-circuit conductors against _____.

a and b

A horsepower-rated _____ having a horsepower rating not less than the motor rating shall be permitted to serve as the disconnecting means.

a or b

A motor can be provided with combined overcurrent protection using a single protective device to provide branch-circuit _____ protection where the rating of the device provides the overload protection specified in 430.32.

all of these

The motor disconnecting means shall not be required to be in sight from the motor and the driven machinery location, provided _____.

all of these

The disconnecting means for a motor controller shall be designed so that it cannot _____ automatically.

close

A _____ shall be located in sight from the motor location and the driven machinery location.

disconnecting means

A motor controller shall open all conductors to the motor where not used as a disconnecting means.

false

In determining the highest rated motor for purposes of complying with 430.24, 430.53(B), and 430.53(C), the highest rated motor shall be based on the rated full-load current as selected _____.

from Tables 430.247, 430.248, 430.249, and 430.250

The motor _____ currents listed in Tables 430.247 through 430.250 shall be used to determine the ampacity of motor circuit conductors and short-circuit and ground-fault protection devices.

full-load

If a motor disconnecting means is a motor-circuit switch, it shall be rated in _____.

horsepower

The motor controller shall have horsepower ratings at the application voltage not _____ the horsepower rating of the motor.

lower than

A feeder supplying fixed motor load(s) shall have a protective device with a rating or setting _____ branch-circuit short-circuit and ground-fault protective device for any motor in the group, plus the sum of the full-load currents of the other motors of the group.

not greater than the largest rating or setting of the

Unless overload protection is provided by other approved means, the minimum number of overload units required for a three-phase alternating-current motor is _____.

three

A branch-circuit overcurrent device can serve as the disconnecting means for a stationary motor of 1/8 hp or less.

true

Each motor shall be provided with an individual controller.

true

Motor control circuits shall be arranged so they will be disconnected from all sources of supply when the disconnecting means is in the open position.

true

Motor controllers and terminals of control circuit devices shall be connected with copper conductors unless identified for use with a different conductor.

true

Open motors having commutators or collector rings shall be located or protected so that sparks cannot reach adjacent combustible material. This shall not prohibit the installation of these motors _____.

on wooden floors

Where the motor short-circuit and ground-fault protection devices determined by Table 430.52 do not correspond to the standard sizes or ratings, a higher rating that does not exceed the next higher standard ampere rating shall be permitted.

true

Motors shall be located so that adequate _____ is provided and so that maintenance, such as lubrication of bearings and replacing of brushes, can be readily accomplished.

ventilation


Set pelajaran terkait

AWS Academy Cloud Foundations - Modules 1 - 8

View Set

Unit 2- Med Surg: Cardiovascular

View Set

History & Geography 808: Twentieth Century World Power - Quiz 1: Overseas Expansion

View Set

IICP, Meningitis, CP: Pediatric Success Neuro

View Set