Motor Controls: Contactors and motor starters

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Author:
johnbowens
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138839
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Motor Controls: Contactors and motor starters
Updated:
2016-05-11 22:39:30
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motor controls JATC IBEW
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motor controls: 4th year
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  1. Delay on Energize (DOE) and Delay On De-energize (DODE) both have what in common?
    Both of these timers start out as energized.
  2. What accelerates switch damage? NJATC, Motor Controls: contactors and starters, 2010, PP 86
    When switches are opened slowly this occurs.
  3. The standard markings for coils on IEC and NEMA starters is what? NJATC, Motor Controls: contactors and starters, 2010, PP 87
    IEC is marked A1 & A2, whereas NEMA is marked without standardization.
  4. IEC starters have what type of reset? NEMA? NJATC, Motor Controls: contactors and starters, 2010, PP 87
    IEC starters have Auto reset but no remote reset. NEMA have neither auto or remote resets.
  5. Which starter contacts are easier to change? IEC or NEMA? NJATC, Motor Controls: contactors and starters, 2010, PP 87
    NEMA. IEC is too expensive due to labor, thus are recommended to be replaced.
  6. What is the difference between a CONTACTOR and a STARTER? NJATC, Motor Controls: contactors and starters, 2010, PP 89
    A CONTACTOR is without overloads, whereas a STARTER has overloads.
  7. When overload protection is included in the load, is it duplicated elsewhere in the branch circuit? NJATC, Motor Controls: contactors and starters, 2010, PP 89
    In a branch circuit load, this is not duplicated. The branch circuit is by definition located after the final over current protection device (OCPD).
  8. Contacts are divided into what categories? NJATC, Motor Controls: contactors and starters, 2010, PP 90
    Normally open power poles, & normally open or normally closed auxillary contacts are the categories of contacts.
  9. Contactors most often have how many power poles and auxillary contacts? NJATC, Motor Controls: contactors and starters, 2010, PP 90
    • These normally have 2-3 power poles and 1-8 auxiliary contacts.
    • Note: Think of single phase which is two incoming conductors and three phase with 3 incoming conductors.
  10. With this you can control a greater number of circuits with a single pilot device. NJATC, Motor Controls: contactors and starters, 2010, PP 90
    You need a contactor to do this.
  11. What is the difference between FLA and FLC? NJATC, Motor Controls: contactors and starters, 2010, PP 93
    There is no difference between these two terms. FLA is full load amperes and FLC is Full load current.
  12. What carries the motor current, The auxillary contacts or the contactor? NJATC, Motor Controls: contactors and starters, 2010, PP 93
    Contactor power poles carry all of the motor current.
  13. What contact is used for electrical hold or start pushbutton sealing requirements in the control circuit? NJATC, Motor Controls: contactors and starters, 2010, PP 93
    Normally open auxiliary contacts are used for this purpose. On a nema starter they are contacts 2 & 3.
  14. How do auxiliary contacts function? NJATC, Motor Controls: contactors and starters, 2010, PP 95
    This type of contact functions just like a normal relay. When the contractor is actuated normally open contacts close and normally closed contacts open.
  15. What type of auxiliary contact provides a higher degree of reliability than the standard auxiliary contact? NJATC, Motor Controls: contactors and starters, 2010, PP 95
    Bifurcated auxiliary contacts provide a higher degree of reliability than the standard auxiliary contacts.
  16. Contactors designed for power control applications other than motors are called what by the Manufacturer? NJATC, Motor Controls: contactors and starters, 2010, PP 95
    Definite purpose or special use contactors are used for this type of application.
  17. What is the most common definite use contactor application? NJATC, Motor Controls: contactors and starters, 2010, PP 95
    lighting contactors fit this description.
  18. The coil of the contactor is controlled by what? NJATC, Motor Controls: contactors and starters, 2010, PP 97
    This is controlled by automatic or manual pilot devices.
  19. The most common pilot devices for lighting are what? NJATC, Motor Controls: contactors and starters, 2010, PP 97
    Timeclocks, photocells or manual switches are considered these.
  20. Lighting contactor control transformers have what range? NJATC, Motor Controls: contactors and starters, 2010, PP 97
    45 to 250 VA
  21. Toggle switches are usually found on what type of manual motor starter? Where as built in pushbuttons are used on what? NJATC, Motor Controls: contactors and starters, 2010, PP 101

    Integral Motors are for how many horsepower?
    Toggle switches are usually found on fractional horsepower manual motor starters, and built in pushbuttons are usually found on integral horsepower manual motors starters.

    More than one HP.  Per the definition of integer: mathematics : any number that is not a fraction or decimal : any whole number or its negative.
  22. In a ladder diagram, from left to right are components shown in order of importance.  T or F?
    True.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 75
  23. Do contacts associated with relays, timers, motor starter, and the like always have the same number or letter designation as the device that controls them?
    Yes. Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 75
  24. In a ladder diagram, devices that perform a stop function are normally wired in what way?
    In series.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 76
  25. When devices are wired in series in a ladder diagram, the are said to have what relationship?
    An AND relationship.  For example, both switch a and b must be closed for the motor to start.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 76
  26. Devices in a ladder diagram that perform a start function are normally wired in what way?
    parallel.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 76
  27. When switches and devices are wired in parallel they are said to have what relationship?
    An OR relationship.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 77
  28. What method of checking fuses of motors and motor control circuits is preferred because more often than not, more than one fuse will be blown in a 3 phase circuit.
    The criss cross method.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 79
  29. What type of wire control is called low voltage or no voltage release?
    two wire control. Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 85
  30. What type of wire control is called low voltage or no voltage protection?
    3 wire control.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 85
  31. On the NEMA starter, termination points 2 and 3 are referred to as what?
    Holding contacts.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 86
  32. The difference between low voltage release (lvr) and low voltage protection (lvp) is what regarding operation of the starter?
    Whether the starter will restart automatically. Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 91
  33. Controllers for industrial motors can be grouped into what broad categories?
    • Controllers can be grouped into 3 broad categories.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 53
    • Manual starters
    • Contactors
    • Magnetic Starters
  34. Manual starters are usually limited to what HP or less for motors?
    10hp or less.  Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 53
  35. If a general use switch is used on a 2hp or less and 300 volts or less motor, what is its ampere rating?
    Not less than twice the FLC rating of the motor. Second Edition Electricians Guide to Motor Controls; Richard Cox. PP 53

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