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Venezuela Falling Behind
Christopher Frank writes "Seems Venezuela's lack of power has finally caught up with them! MSNBC has the story: 'If you thought Venezuela's political crisis seemed to be dragging for an impossibly long time -- you were right. In a bizarre mass-malfunction, Venezuela's clocks are ticking too slowly due to a power shortage weakening the electric current nationwide. By the end of each day, the sluggish time pieces still have another 150 seconds to tick before they catch up to midnight.'"
Can someone please point me to a good synopsis of the last year in the country?
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The town of Highland Illinois had a company that made motors that shipped all over the world. At night the local power company would slow down the frequency from 60HZ to 50 HZ for testing of the motors and then catch up all the clocks in town by running at 62HZ for 5 times as long as the elapsed test sequence. This whole process had to be completed before people had to get up for work in the morning.
This was about 20 yesrs ago so things have probably changed by now.
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These are extremely reliable clocks. I still have one. Mine was made in Ashland, Massachusetts (USA) in 1941. Its still running. Keeps good time. I did have to change the line cord though.. the old one's insulation got so brittle that just bending the wire would shatter the plastic. They did not make decent flexible insulation in those days.. but the motor itself is still fine.. its alternating layers of winding and wax paper. No brushes.
Internally, they are shaded-pole induction motors, which use the reversals of the incoming power to generate a rotating magnetic field, upon which a magnetized rotor follows in exact sync. If the power goes off for an hour, the clock loses an hour. It restarts when it sees power again. Its not the most efficient clock though, it uses about 10 watts of power.
About every appliance clock that had hands or those little digital "flappers" used this design.
For what its worth, a lot of the old record players used a larger version of the same motor that drives the clocks - and it was used as a cheap means of spinning the turntable at 33, 45, or 78 RPM by means of selecting a different radius on the mechanical friction-drive transmission that drove the turntable from the motor spindle. It was a simple thing - basically a little moveable rubber-rimmed wheel that rested on one of three different radius areas of the motor spindle, then drove the inside of the turntable from that. Very inexpensive, yet robust. ( but a bit noisy - a little drive noise always was present, and we used "wow" and "flutter" to describe the low and high speed mechanical aberrations of turntable rotation).
Probably more than you wanted to know about these things.. but I thought I would toss it in for anyone interested.
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there was an attempted coup, in which the US was allegedly involved.
whether involved or not, Bush was pretty delighted at the replacement of the elected president with a dictator. and there were at least talks between the white house and the coup plotters in which the white house obviously didn't do a very good job in discouraging the coup plotters.
for a collection of references to articles giving a good background on this issue, see my website (comments, additional info much appreciated).
also provided on the same page is a history of similar coups over the past 50 years in Latin America which occurred to governments in response to actions similar to what Chavez has been doing (land reform, nationalisation of oil/industries). basically anything to alleviate the poor majority. it is this historical pattern which gives the biggest indication that the CIA may be behind it. however, the difference in venezuela is that the CIA supposedly stopped performing these coups.
perhaps the failure of the coup indicates how much harder it is for them to pull them off today (they have to be much more careful to leave no fingerprints, as the public is much less likely to support them without the cold war excuse).
The two are related. All those generators interconnected to each other via the power lines, turn together in synchronized motion. If the sum of all power consumption is not matched by the correct rate of energy input (ultimately, torque applied) to the system, those generators will necessarily slow down.
The AC frequency is directly determined by the rotational speed of the generators. The magnetic field of the rotor induces that AC current in the stator windings as it turns, so the speed of rotation must be maintained if the AC frequency is to be correct.
Why they don't disconnect some loads (eg, rolling blackouts) to keep the consumption balanced with their energy input is a good question?
The really interesting thing about power grids is how the all those generators work together in synchronous motion. Every single one of them turns at the same speed and all those rotors are at (almost) exactly the same angular position at the same instant (or equivilant angular position in the case of different generator designs with different numbers of windings). If any one generator goes not receive enough torque applied, it acts as a motor and the rest of the grid supplies power to it to keep it turning in sync motion with the rest.
The power grid, as a whole, must be very carefully managed to keep the energy input (torque on the generators) balanced with the consumption of all the loads. If it is not managed properly, as appears the be the case here, the frequency can drift. That's actually a very big problem, not just because of all those clocks and old televisions using the line frequency for timing, but because all those transformers and motors attached to the grid were designed to operate at the specified frequency. As the frequency lowers, approaching even somewhat closer to DC, the magnetizing currents increase. That puts a lot of extra stress on all those motors and transformers. Very bad.
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Every once in a while you hear about a utility that gets this wrong. About 10 years ago this happened at a power plant in Kewaunee, Wisconsin. Seems the technician who was responsible for bringing a new generator online messed up when synchronizing the generator to the phase on the power grid. He managed to align it exactly 180 degrees out of phase, then threw the switch to connect the generator to the grid and... BAM! Ripped right off its mounting.
Most clocks, I don't know about you but I use have two digital plug in clocks, they both use AC power rectified from a step down transformer to DC power using a classic 'bridge' rectifier, then use a voltage regulator chip to smooth out and regulate voltage to a much smaller but consistent DC voltage, typicaly 3-12 volts DC. The older 780x series of voltage regulator chips were good, but the more modern chips are much better. The amount of power on the grid fluctuates every day, however the frequency doesn't. Which, for older mechanical clocks would make a difference because an AC motor rotates in a direct relation to the input voltage frequency. For the type of clocks most people use it would make a difference because the chips inside use a steady DC current, which brings me to my next point.
The problem that is likely causing your clocks to get off sync are cheap and shoddy timing circuits. An example of this would be the shoddy clock chip on the old IBM clones. This chip (Intel 8253) has a very low clock tick-resolution ~18.2 times a second, which was fine for polling a joystick, etc on the older boxes, but is terrible for accurate time-keeping. Most digital watches have millions of 'clock-ticks' per second.
Actually it would be quite easy to do (in theroy, I have no first hand knowledge of this). All you need is several hundred or thousand strands of carbon filamnet, and airborn dispersial mechanisim. The "bomb" will just explode over, or nearly over the power lines, preferably high voltage lines, since they are not covered with insulating material. Current technology allows for this type of bomb. The filiments, having been dispersed in the air will float down and land on the wires. The filiments will either short out between the wires or from wire to ground. With high voltage lines it not that difficult to get the current to flow to ground. Even if 99% of the carbon filiments do not hit the wires, the remaining 1% would probably be enough to quickly cause an overload on the line, and flip the big circuit breakers.
The real benifit of this it that the power grid is quickly overloaded, the saftey equipment trips to pretect the generators, and no real perminant damage happens to the over all system.
This takes out the enimies ability to distribute power for a short period of time without long term damage to the over all system. Perfect for an invading force.