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So You Call Yourself A ME?

Discussion in 'Question of the Day' started by ship, Dec 26, 2005.

  1. ship

    ship Senior Team Emeritus Premium Member

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    58) Define Dirty Power and the three causes of it.
    21) On a 3" Fresnel or "Inkie" they origionally used single contact bayonet lug lamp bases (BA-15s) but now use dual contact bayonet (BA-15d) bases. Why would a old single contact bayonet lamp in a new double contact lamp base explode, but a double contact lamp in an old single contact base not do anything?
    46) What two reasons make it necessary to ground a transformer?
    53) What is the difference between a generator/alternator, and dynamo?
    55) What is the only equipment which can be installed before the service disconnecting means?
    60) What piece of equipment is designed to do the following: 1) during normal operations, not interfere with the circuits they protect, 2) transfer the excess voltage to ground in a surge, not to exceed the voltage rating of the equipment it protects, 3) Clamping speed must be fast enough to prevent damage to the protected equipment, and 4) be capable of withstanding surges without damage to itself.
    61) What are the two purposes of grounding?
    62) Power relays are required for lighting booths when what condition exists?
    63) A small voltage imbalance will produce a proportional or large current imbalance?
    64) A simple inductive ballast is what?
    70) Which is the proper way (most accurate way) of determining power requirements, A) figure out how many thousands of watts of watts is the total load on the system, and divide by 1,000 than times that figure by 8.3, multiply that figure by 1.2 for safety and divide that figure by 3 for the phases, or B) distribute the load, take total wattage of each leg, divide by 120 to get the amperage, multiply by 1.2 for a safety factor, and round up to the next size service available for the load?
    76) The unit of electrical pressure is called the what?
    77) The ampere is a unit of electrical what?
    79) The drier the area around a grounding rod, the higher or lower the resistance to ground?
    80) Over-loaded fuses will have a clear or darkened window?
    81) One Hz is the A) amount of time between center of two peaks of current B) the amount of peaks in 60 seconds C) the amount of peaks+valleys in one second D) the amount of time between the centers of one peak and one valley of a wave?
    91) Causes of high voltage drop are: excessively long cable runs, poor connections, and what?
    103) The resistance of a conductor is directly proportional to its what?
    104) The resistance of a conductor is inversely proportional to what?
    105) Does temperature affect resistance of conductors, if so, would higher color temperature lamps be higher wattage at the end of their lamp life, or does wattage always stay the same in a lamp in-spite of the age of a lamp? What does this have to do with superconductivity?
    107) What is the skin effect, and what does it have to do with voltage loss and capacity?
    108) What is the difference in resistance between series and parallel?
    109) The total resistance of the combined resistances in this circuit is always less than the resistance of the lowest-value resistor in this circuit. The combined total resistance of a number of unequal resistances in this circuit is equal to the reciprical of the sum of the reciprocals of the individual resistances. What type of circuit is this, Series or Parallel?
    110) Voltage drop in this type of circuit equals the sum of the voltage drops of the resistors in the circuit, and thin turn equals the voltage at the supply source. Also the current in this circuit is the same throughout the circuit. What type of circuit is this?
    111) Explain the effect of induced emf.
    117) What is the difference between electricity and magnetism?
     
  2. CHScrew

    CHScrew Active Member

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    76) Kilovolt (kV)
    77) Unit of electric current
     
  3. TheHeadhunter

    TheHeadhunter Member

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    109) Parallel
    110) Series
     
  4. ship

    ship Senior Team Emeritus Premium Member

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    76) The unit of electrical pressure is called the what?

    A kV is a unit of voltage, but isn't a Volt also?
     
  5. sound_nerd

    sound_nerd Active Member

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    60) GFCI
    77) measurement

    about all I can think of right now, without hitting the texts...
     
  6. Radman

    Radman Well-Known Member

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    21) On a 3" Fresnel or "Inkie" they origionally used single contact bayonet lug lamp bases (BA-15s) but now use dual contact bayonet (BA-15d) bases. Why would a old single contact bayonet lamp in a new double contact lamp base explode, but a double contact lamp in an old single contact base not do anything?

    Now I don't think it would actually explode, but the single contact lamp would short the two contacts of the double contact base, while the two contacts on a double contact lamp would both be touching the same contact on the single base, with no contact to the other contact, therefore nothing.


    55) What is the only equipment which can be installed before the service disconnecting means?

    NEC 230.82 (2002 edition)
    Code:
    (1) Cable limiters or other current-limiting devices.
    (2) Meters, meter sockets, or meter disconnect switches nominally rated not in excess of 600 volts, provided all metal housings and service enclosures are grounded.
    (3) Instrument transformers (current and voltage), high-impedance shunts, load management devices, and surge arresters.
    (4) Taps used only to supply load management devices, circuits for standby power systems, fire pump equipment, and fire and sprinkler alarms, if provided with service equipment and installed in accordance with requirements for service entrance conductors.
    (5) Solar photovoltaic systems, fuel cell systems, or interconnected electric power production sources.
    (6) Control circuits for power-operable service disconnecting means, if suitable overcurrent and disconnecting means are provided.
    (7) Ground-fault protection systems where installed as part of listed equipment, if suitable overcurrent protection and disconnecting means are provided.
    

    61) What are the two purposes of grounding?

    To prevent the buildup of hazardous voltages, and to provide a conducting connection to the earth.


    70) Which is the proper way (most accurate way) of determining power requirements, A) figure out how many thousands of watts of watts is the total load on the system, and divide by 1,000 than times that figure by 8.3, multiply that figure by 1.2 for safety and divide that figure by 3 for the phases, or B) distribute the load, take total wattage of each leg, divide by 120 to get the amperage, multiply by 1.2 for a safety factor, and round up to the next size service available for the load?

    B


    76) The unit of electrical pressure is called the what?

    volt


    77) The ampere is a unit of electrical what?

    current


    79) The drier the area around a grounding rod, the higher or lower the resistance to ground?

    lower


    80) Over-loaded fuses will have a clear or darkened window?

    darkened


    81) One Hz is the A) amount of time between center of two peaks of current B) the amount of peaks in 60 seconds C) the amount of peaks+valleys in one second D) the amount of time between the centers of one peak and one valley of a wave?

    C


    91) Causes of high voltage drop are: excessively long cable runs, poor connections, and what?

    greatly oversized cable


    117) What is the difference between electricity and magnetism?

    electricity is carried out by electrons, magnetism is carried out by fields



    I would've answered more but most of them I only got part of the question.
     
  7. ship

    ship Senior Team Emeritus Premium Member

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    21) Correct - but out of experience it does tend to.
    55) Well done.
    61) Correct
    70) Correct
    76) Correct
    77) Correct
    79) Incorrect "Ways to improve grounding rod efficiency, (1) wet or place rod near where earth will get wettest. (2) Install more rods and interconnect them at least ten feet apart. (3) Salt the ground around the rod once a year, if earth around rod contains at least 1% salt, resistance can drop by as much as 90%, or 25 ohms can become 2.1/2 ohms.
    Note: the dryer the ground around the rod, the greater the resistance to ground is."

    I have forgotton the source of this information in not noting it when I copied it at the time.

    80) Incorrect "Blown Fuses: Over loaded Fuses will have a clean window as the wire has broken without much heat build up (it wears down.)
    Short circuited Fuses have a darkened window as the wire as heat vaporizes the wire in a short time." Again - the same unknown book. This for the most part would also be the same for lamps.

    91) Would you like to re-visit your answer?
    117) Correct

    What questions are not understood? Those are probably questions that should be restated for others also.
     
  8. Radman

    Radman Well-Known Member

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    79) mulligan. I thought it out backwards ("well, if it was wet the resistance would be lower") and forgot to switch back into forward gear before I wrote my answer

    21) Interesting it would cause the lamp to actually explode. I've only changed the lamp in one of those a couple times, never put in the wrong lamp.

    80) I was a little unsure of that answer to begin with, I assumed you were talking about the kind of fuses that used to be in houses, which I haven't used since I was like 8. I guessed they would be kinda like the breakers that show a flag in the window then they are tripped. But I completely forgot those little glass fuses I see everwhere. Those definitely clear up (unless they vaporize and leave black residue on the window).

    91) too small of conductor?

    -------------------------------------------------------------

    One question I didn't get was 111, I didn't recognize the acronym for ElectroMagnetic Field.

    60 has me stumped, I wanted at first to say circuit breaker, but it doesn't even touch the ground so that can't be right, then I wanted to say GFCI, but I don't think those divert the extra current to ground, they just open the circuit in the event of a ground fault.

    63 doesn't make sense to me at all.


    One good question I have to add is "What is the percent conductivity of copper?"
     
  9. Radman

    Radman Well-Known Member

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    Is 60 a TVSS?
     
  10. ship

    ship Senior Team Emeritus Premium Member

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    I'm holding 60) off in saying what piece of store bought equipment is availabe everywhere from the grocery store to the lumber yard.

    63) If your load is un-balanced, what is reflected in the neutral in carrying this inbalance?

    91) Correct
    21) The lamp persay did not explode, the short on the other hand melted down all metal in the connection in a very fast way with a big spark. The smoke also turned the fixture inside black. I would call that an explosion even if there was not a shower of glass to follow.
     
  11. Radman

    Radman Well-Known Member

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    21) Ah, ok that makes sense then. I could see that easily.


    60) Surge protector popped into my mind.


    63) Could that be some wacky harmonics from an incomplete sine? Or something like that...
     
  12. ship

    ship Senior Team Emeritus Premium Member

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    63) you are getting there in a "My neutral is showing 180v to ground type of way." This given I remember a phone call one night from a crew chief correctly. Three phase and a phone call one night. Stuff is powered from a generator. Crew chief is clueless also. What are the steps for correcting this problem?
     
  13. Radman

    Radman Well-Known Member

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    Check for poor connections, generator output, I'm kinda outta my game on this one, never worked with a genny.
     

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