Motor_Controls_Test

where the motor short circuit and ground fault protection devices determined by table 430.52 do not correspond to the started sizes or ratings, a higher rating does not exceed the next higher standard ampere rating shall be permited

true

If a motor has a current draw of 20a at 240v, what will the amperage be if 480v is applied?

10a

conductors supplying several motors shall not be used 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

the maximum recommended size of a dual-element, time delay fuse for a 50hp 460v motor rated at 65 fla is _______

125 A

if a 480v three phase motor control center feeds a 50hp motor, a 40hp motor, and a 10hp motor, the minimum feeder ampacity is ____

147.25a

the maximum rating or setting of an inverse time breaker used as the motor branch circuit short circuit and ground fault protection device for a single phase motor is ___ percent of the full load current given in table 430.248

250 percent

what is the maximum value for short circuit protection for multi motor branch circuits

250 percent of the smallest motor

torque requirements for motor controls circuit devices terminals shall be minimum of _____ lbs-in

7 lbs

for stationary motors of 2 hp or less and 300 v or less on ac circuits the controller can be an ac rated only general use snap swith where the motor full load current rating is not more than percent of the rating of the switch

80 percent

motor control calculations

F= 3/0 G= 8 H= 14

a motor disconnecting means can be a listed____-

any of these

the most effective method of power factor correction is the installation of

capacitors

When sizing equipment grounding conductors for branch circuits of continuous duty motors ___

combine the rating of each branch circuit OCPD and when applicable the rating of each overload protective device

in addition to short circuit protection, MSCPs may also serve as a ___

diconnecting means

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

the synchronous speed of an induction motor is determined by the number of stator poles and the ____

frequency in hertz

in determining the highest rated motor for purposes of complying with 430.24, 430.53b, 430.53c, the highest rated motor shall be based on the rated full load current as selected ___

from tables 430.247, 430.248, 430.250

when a motor is oversized, a higher degree of overload protection can be provided by sizing the fuses based on the ____

full load current

to calculate the maximum safe load that a motor may be expected to carry contunuously at its rated voltage and frequency, the service factor is multiplied by the ___

horsepower rating

when used for short circuit protection of motor branch circuits, which of the following must be adjustable and used in conjunction with combination motor starters

instantaneous trip circuit breakers

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

lower than

open motors having commutators or collector rings shall be located or protected so that sparks cannot reach adjacent combustible materials. this shall not prohibit the installation of these motors ____

on wooden floors

the motor branch circuit short circuit and ground fault protection device shall be capable of carrying the ___ current of the motor

starting

one of the three factors will cause a three phase motors magnetic field to rotate is that the ___

stator windings around the inside of the motor are arranged in a specific manner to induce rotation

which of the following is true concerning the starting current of an induction motor at the moment the circuit is energized

the current rises rapidly

unless overload protection is provided by other approved means. the minimum number of overload units required for a three phase alternating current motoris _____

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 identifued for use with a different conductor

true

the disconnecting means for the controller and motor shall open all ungrounded supply conductors

true

if the total resistance of two motor windings connected in parallel is 24o and 240v is applied to the circuit, how much current will flow

10a

for ordinary motors, the short circuit/ground fault protection for non time delay fuses are sized at what percentage of the motor full current?

300 percent

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 310.15b16 60 degree conductors

300 percent

which of the following lists the full load currents for three phase motors with a known winding type, horsepower, and voltage

NEC TABLE 430.250

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

all of these

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 percent

branch circuit conductors supplying a single continuous duty motor shall have an ampacity not less that ___rating

125 percent of the motor's full load current rating as determined by 430.5a1

if the total resistance of two motor windings connected in parallel is 20 ohms and 240v is applied to the circuit, how much current will flow

12a

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

which of the following describes MSCPs

Fuse like devices designed for use only in a special type of fusible switch combination motor starter

the requirements for torque motors, shaded pole motors, permanent split capacitor motors, and AC adjustable voltage motors can be found in ____

NEC section 430

for general motor application, the motor branch circuit short circuit and ground fault protection device shall be sized based on the ____ values

NEC tables

overcurrent protection for motor control circuits shall not exceed _____ percent if the conductor is based on table 310.15b17 and does not extend beyond the motor control equipment enclosed

400 percent

Good electrical protection for a motor includes both proper overload protection and ____

current limiting short circuit protection