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  1. W

    High power factor! Is it Good/Bad? Why?

    Is a high power factor good or bad? If you are talking about evaluating the insulation of a device (a transformer for example) a high power factor is bad. Just thought I'd muddy the water a little.
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    9th Harmonic and Ma Bell

    The only industrial load is a 1200 Hp gas line pump, which does not appear to be the culprit (i.e., the harmonic still exists when the pump is down). The rest of the area is rural load. The link was good, but I was looking for something the phone company could put on their equipment.
  3. W

    9th Harmonic and Ma Bell

    We have a local telephone company complaining to our utility that they have noise on their system. We have investigated and found a fairly significant 9th harmonic on the power line. This seems to play havoc with phone systems. What is a likely cause of a 9th harmonic? We are a rural utility...
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    What is rated load ?

    A transformers "rated load" is rated in VA (volts X amps), not power (since the manufacturer has no idea what kind of load will be put on it). The rating of the transformer is based on the heat build up from current flow through the windings. At rated voltage and rated amps, you would have...
  5. W

    Alternative energy sources to generate electricity?

    Geothermal. Look at Iceland.
  6. W

    What are these ? in a motor?

    It sounds like you are describing a shaded pole motor. The copper loops provide a phase shift for torque purposes.
  7. W

    Why is the fuse blowing?

    As Russ pointed out, 230volts X 10 amps = 2300watts, well below both of your predicted loads. Simply put, you have too much plugged in.
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    Topics for electrical engineering ethics

    Discuss the ethics of a professor that requires a student to communicate in electronic form but does not respond.:yuck:
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    Resistance of meter coils

    True, but in terms of revenue metering, assuming a plus or minus 6% variation in voltage as irrelevant to metering accuracy would be tantamount to stealing. In Texas, the Public Utility Commision requires plus or minus 2% (or less) error on house meters (most of which in practice run within...
  10. W

    Resistance of meter coils

    Voltage on a distribution circuit is never constant since it will vary with load and the load is never constant. Line voltage regulators will maintain a usable voltage, not a constant one.
  11. W

    Resistance of meter coils

    There are 2-wire meters that read 120 from hot leg to neutral. They also have a potential coil. The theory is the same as the 3-wire meter mentioned above, except the there is only one current coil and (as mentioned) the potential coil is 120 volts.
  12. W

    Question about balance of el. energy production and consumption

    The voltage at the generator is controlled by the excitation winding. As noted, the steam resources respond to speed, which is affected by the current draw in the line from the load. If the voltage drops, the feild of the excitation winding is increased to maintain voltage. A voltage...
  13. W

    Credit card & magnet

    Yes. The situation you described may not do it, but a magnetic field can mess up a credit card or Hotel key type device. At a recent meeting, the group toured a generator facility. Everyone that entered the room had to have Hotel desk re-do their keys when they got back. No one could get...
  14. W

    Basic electricity

    http://www.allaboutcircuits.com/vol_1/index.html
  15. W

    Why 220@50hz and 120@60hz?

    He's wrong. Edison was desperate in his attempts to discredit Westinghouse's AC system and was resorting to all sorts of public relation propaganda to prove how dangerous it was (including the promotion of the electric chair). It was hardly to Westinghouse's (or Tesla, his top engineer that...
  16. W

    Power generation and distribution

    While this is true, it is also true that extremely long transmission lines have capacitive reactance issues since each conductor serves as a "plate" of the capacitor and the air between is the dielectric. Just muddying the water a little:biggrin:
  17. W

    Power generation and distribution

    Try re-phrasing the question.
  18. W

    Electrical Leakage from Cars?

    Actually it IS you. The above was just to placate Gnophos. :biggrin:
  19. W

    When Transformers Asplode

    Typically you will have a main 3 phase feeder coming down a street. There may be transformers directly on this line and each one will be fused (usually to about twice its full load rating). There will also be single phase lines "tapping" off of the 3 phase going down alleys, across pastures...
  20. W

    Earth & neutral connections

    It would still work. Single insulated ungrounded devices worked for years. Oh yeah, lots of people got electricuted, too. Any impedance between your PC and the ground at the service entrance would raise the potential of the case of your PC. If you lost the neutral connection, the case would...
  21. W

    When Transformers Asplode

    I'm still thinking what you saw were the lines slapping together in the high winds and snapping from the weight of the ice, not asploding :smile: transformers.
  22. W

    When Transformers Asplode

    No. The oil used in transformers is designed for its dielectric properties, not its lubricity. However, it is close enough to diesal that it can be mixed and run in a diesal engine.
  23. W

    Electrical Leakage from Cars?

    Precisely!
  24. W

    When Transformers Asplode

    As mentioned, "heat" refers to the transformers' temperature, not the ambient temperature. Winter loads typically overload transformers. It probably slapped the phases together and blew a tap fuse back up the line. The transformer most likely wasn't involved. Again, was it the...
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    Transformer core saturation

    I'm trying to understand what happens to a distribution transformer in relation to overvoltage conditions (in terms of saturation and current flow; not insulation failure). I understand that once the voltage has risen high enough to drive the magnetic core past the saturation point, that the...
  26. W

    110 Vs 250

    Since power (in watts) is essentially volts times amps (ignoring the phase angle), doubling the voltage allows you to halve the amps. The same amount of work is done. Lower amps allows you to use smaller gauge wire (cheaper) and has lower line losses (I squared R) and less voltage drop in the...
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