PEC - Chapter 4 (Sheet3-Part2)

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Camskie
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306459
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PEC - Chapter 4 (Sheet3-Part2)
Updated:
2015-08-17 07:38:41
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camille chapterfour
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Chapter4
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  1. Conductors supplying several motors, or a motor(s) and other load(s), shall have an ampacity not less than __ percent of the full-load current rating of the highest rated motor plus the sum of the full-load current ratings of all the other motors in the group, as determined by 4.30.1.6(a), plus the ampacity required for the other loads
    125
  2. Feeder tap conductors shall have an ampacity not less than that required by Part II, shall terminate in a branch-circuit protective device, and, in addition, shall meet one of the following requirements:

    (1) Be enclosed either by an enclosed controller or by a raceway, be not more than __ mm in length, and, for field installation, be protected by an overcurrent device on the line side of the tap conductor, the rating or setting of which shall not exceed __ percent of the tap conductor ampacity

    (2) Have an ampacity of at least one-third that of the feeder conductors, be suitably protected from physical damage or enclosed in a raceway, and be not more than __ m  in length

    (3) Have an ampacity not less than the feeder conductors
    • 3 000
    • 1 000
    • 7.5
  3. (More than 1HP)
    Separate Overload Device. A separate overload device that is responsive to motor current. This device shall be selected to trip or shall be rated at no more than the following percent of the motor nameplate full-load current rating:

    Motors with a marked service factor 1.15 or greater (____)

    Motors with a marked temperature rise40°C or Less (___) 

    All other motors (____)
    • 125%
    • 125%
    • 115%
  4. (More than 1HP)
    Thermal Protector. A thermal protector integral with the motor, approved for use with the motor it protects on the basis that it will prevent dangerous overheating of the motor due to overload and failure to start. The ultimate trip current of a thermally protected motor shall not exceed the following percentage of motor full-load current given inTable 4.30.14.2, Table 4.30.14.3, and Table 4.30.14.4:

    Motor full-load current 9amperes or less (____)

    Motor full-load current from9.1 to, and including, 20 amperes (____)

    Motor full-load current greater than 20 amperes (____)
    • 170%
    • 156%
    • 140%
  5. For motors larger than __hp, a protective device having embedded temperature detectors that cause current to the motor to be interrupted when the motor attains a temperature rise greater than marked on the nameplate in an ambient temperature of __°C
    • 1 500
    • 40
  6. Where the sensing element or setting of the overload relay selected in accordance with 4.30.3.2(a)(1) and 4.30.3.2(b)(1) is not sufficient to start the motor or to carry the load, higher size sensing elements or incremental settings shall be permitted to be used, provided the trip current of the overload relay does not exceed the following percentage of motor nameplate full-load current rating:

    Motors with marked service factor 1.15 or greater (___)

    Motors with a marked temperature rise 40°C or Less (___)

    All other motors (___)
    • 140%
    • 140%
    • 130%
  7. 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
    400
  8. (Motors on General-Purpose B.C.)

    Where a motor is connected to a branch circuit by means of an attachment plug and receptacle and individual overload protection is omitted as provided in 4.30.3.12(a), the rating of the attachment plug and receptacle shall not exceed __ amperes at __ volts or __ volts
    • 15
    • 125
    • 250
  9. Exception No. 1: Where the setting specified in Table 4.30.4.2 is not sufficient for the starting current of the motor, the setting of an instantaneous trip circuit breaker shall be permitted to be increased but shall in no case exceed __ percent of the motor full-load current for other than Design B energy-efficient motors and no more than __ percent of full-load motor current for Design B energy-efficient motors
    • 1 300
    • 1 700
  10. Trip settings above __ percent for other than Design B energy-efficient motors and above __ percent for Design B energy efficient motors shall be permitted where the need has been demonstrated by engineering evaluation. In such cases, it shall not be necessary to first apply an instantaneous trip circuit breaker at __ percent or __ percent
    • 800
    • 1 100
    • 800
    • 1 100
  11. Exception No. 2: Where the motor full-load current is __ amperes or less, the setting of the instantaneous-trip circuitbreaker with a continuous current rating of __ amperes or less in a listed combination motor controller that provides coordinated motor branch-circuit overload and short-circuit and ground-fault protection shall be permitted to beincreased to the value marked on the controller
    • 8
    • 15
  12. Synchronous motors of the low-torque, low-speed type (usually __ rpm or lower), 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
    • 450
    • 200
  13. Motor Short-Circuit Protector.
    A motor short-circuit protector shall be permitted in lieu of devices listed in Table 4.30.4.2 if the motor short-circuit protector is part of a listed combination motor controller having coordinated motor overload protection and short circuit and ground-fault protection in each conductor and it will open the circuit at currents exceeding __ percent of motor full-load current for other than Design B energy-efficient motors and __ percent of motor full-load motor current for Design B energy-efficient motors
    • 1 300
    • 1 700
  14. (Control Circuit Transformer)
    Control circuit transformers rated less than __ volt-amperes (VA) and that are an integral part of the motor controller and located within the motor controller enclosure shall be permitted to be protected by primary overcurrent devices, impedance limiting means, or other inherent protective means
    50
  15. (Control Circuit Transformer)
    Where the control circuit transformer rated primary current is less than __ amperes, an overcurrent device rated or set at not more than __ percent of the rated primary current shall be permitted in the primary circuit
    • 2
    • 500
  16. For a stationary motor rated at __ hp or less that is normally left running and is constructed so that it cannot be damaged by overload or failure to start, such as clock motors and the like, the branch-circuit protective device shall be permitted to serve as the controller
    1/8
  17. For a portable motor rated at __ hp or less, the controller shall be permitted to be an attachment plug and receptacle
    1/3
  18. Exception No. 1: For motor circuits over __ volts, nominal, a controller disconnecting means capable of being locked in the open position shall be permitted to be out of sight of the controller, provided the controller is marked with a warning label giving the location of the disconnecting means
    600
  19. For stationary motors of __ hp or less, the branch-circuit overcurrent device shall be permitted to serve as the disconnecting means
    1/8

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