Switchgear

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Author:
johnbowens
ID:
125064
Filename:
Switchgear
Updated:
2012-01-07 18:47:13
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Switchgear IBEW JATC
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Switchgear
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  1. The equipment intended to connect and disconnect power circuits are known collectively as what? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 15 (NC set: Switchgear)
    Switchgear.
  2. Switchgear are generally divided into how many groups and what are they? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 16 (NC set: Switchgear)
    • Four:
    • Disconnect or isolator switches,
    • load brake switches,
    • circuit breakers, and
    • contactors.
  3. Load brake switches are, or are not, designed to interrupt fault currents? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 17 (NC set: Switchgear)
    Load brake switches are not designed to interrupt fault currents; they must remain closed through faults.
  4. Indoor breakers are usually what in regards to location and number, whereas outdoor breakers maybe what? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 17 (NC set: Switchgear)
    Indoor breakers are usually in metal cabinets as part of the switchgear lineup, Where as outdoor breakers maybe standalone units.
  5. What must be remembered when using vacuum circuit breakers? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 17 (NC set: Switchgear)
    Chop current's as high as 3 to 5 A if the breaker is ahead of a transformer can generate a high-voltage exciting inductance of the transformer, and this can be passed on to secondary circuits.
  6. Regarding chop current the required voltage control can be obtained with what on the primary and what on the secondary of the transformer? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 17 (NC set: Switchgear)
    Arrestors on the primary and MOV's on the secondary.
  7. Nearly all relays are operated from what? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 18 (NC set: Switchgear)
    Current transformers and most are now solid state.
  8. The real workhorses of switchgear are what? hint; they're rated for many thousands of operations. Keith H. Suker, Power Electronics design: a practitioner's guide, PP 18 (NC set: Switchgear)
    Contactors: These are Electromagnetically operated switches that can be used for motor starting and general-purpose control.
  9. Contactors can employ what at low voltages and medium voltages? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 18 (NC set: Switchgear)
    Airbrakes at low voltages or vacuum contacts at medium voltages.
  10. Most contactors have what type of operating coils? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 18 (NC set: Switchgear)
    Continuously energized operating coils and open when control power is removed.
  11. Motor starters can handle overloads of how many times rated or more? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 18 (NC set: Switchgear)
    Five times rated overload.
  12. Lighting contactors also have overload ratings for? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 18 (NC set: Switchgear)
    Incandescent lamps.
  13. MOVs will limit the developed voltage on opening but will be of no help in limiting what? Keith H. Suker, Power Electronics design: a practitioner's guide, PP 19 (NC set: Switchgear)
    DI/DT that may interfere with other circuits.
  14. Control and emergency transfer switch handles or pushbuttons shall be in a readily accessible location at an elevation of not over what? What would be an exception? NEC 490.41a (NC set: Switchgear)
    6'7" An exception would be any switches requiring more than 50 pounds of force be at 66 inches or less in height.

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