Electrical Systems Chapter 11

Motor nameplates shall include the rated horsepower if ___ HP or more.

1/8

The length of flexible cords used to supply A/C units shall not exceed ___' for 120 V units.

10'

The disconnecting means for motor circuits shall have an ampere rating not less than __ percent of the full-load current rating of the motor.

115

The disconnecting means for motor circuits are required to have an ampere rating of at least ___% of the FLC rating of the motor for circuits rated 1000 V or less.

115%

Table ________ is used to determine the current ratings of DC motors.

430.247

Table ________ is used to determine the current ratings of 1-phase motors.

430.248

Table ___ is used to determine the current rating of 3 phase AC motors.

430.250

The code letter or locked rotor amps shall be listed on the nameplates of motors rated ___ HP or more.

1/2

An overload device used to protect continuous-duty motors (rated more than 1hp) shall be selected to trip or rated at not more than _____ percent of the motor nameplate current rating for motors with a marked service factor not less than 1.15.

125

Branch-circuit conductors supplying a single motor shall have an ampacity of ___% of the FLC rating as indicated on the appropriate FLC table.

125%

The maximum rating or setting of motor short-circuit and ground-fault protective devices for a single-phase motor is _____ percent for a time-delay fuse.

175

Cord-and-plug-connected compressors and equipment shall be rated no greater than ___A on 120v circuits.

20

A/C units that operate at ___ or less may be cord and plug connected.

250v

The ___ is the device in a motor circuit which turns the motor ON or OFF.

Controller

Small motors rated 150 W or less shall be marked "impedance protected"

False

The ampere rating of a fusible disconnect is determined by the size of fuse being used in the motor branch circuit.

False

A(n) ___ refrigerant motor-compressor is a combination compressor and motor enclosed in the same housing, having no external shaft or shaft seals, with the motor operating the in the refrigerant.

Hermetic

A(n) ___ device is a pilot light, buzzer, horn, or other type of alarm.

Indicating

The ___ branch circuit is the point from the last fuse or circuit breaker protecting the motor circuit out of the motor.

Motor

A(n) ___ is the operation of equipment in excess of normal, full-load current rating, or a conductor subject to current in excess of the rated ampacity.

Overload

A/C and refrigeration equipment with several motors can be considered as a single machine.

True

The larger a motors full load table current, the less the percentage of the increase in sizing the thermal protector that is an integral part of the motor.

True

The overcurrent protection for an MCC may be located ahead or within the MCC.

True

The rated frequency shall be given on the nameplate of a motor controller.

True

The motor _____ current as listed in Tables 430.247 through 430.250 must be used for sizing motor-branch circuit conductors and short-circuit, ground-fault protection devices.

full-load

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

horsepower

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 as listed in the NEC

If the service factor and temperature rise are not marked on the nameplate, the nameplate current should be multiplied by ___%.

25%

The maximum rating or setting of motor short-circuit and ground-fault protective devices for a single-phase motor is _____ percent for an inverse-time breaker.

250

Equipment shall be located within ___' and be visible to be considered within sight.

50'

The branch circuit conductors on the line side of the controller for a multi speed motor shall be at ___% of the highest of the FLC rating shown on the motor nameplate.

90%

Overload relays and other devices for motor overload protection that are not capable of opening _____ shall be protected by fuses or circuit breakers. A. short circuits B. clearing overloads C. ground faults D. a and c

D. A and C

A plug and receptacle may serve as a controller for stationary motors up to 2 HP.

False

The winding type shall be given on the nameplate of a DC motor.

True

A ___ is an assembly of one or more enclosed sections with a common power bus and primarily containing motor control units.

Motor control center