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Thread: The 2014 Nobel Prize in Physics - Press Release

  1. #41
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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Fenton View Post
    Harmonics from ( older ) VFDs/ inverters are only an issue if that VFD is installed in the field, like a industrial application where those harmonics can back feed and degrade your overall power factor.

    Low power factors can cause component, motor and transformers to over heat and your utility bill to go up.

    Newer VFDs-inverter have carrier frequency inductors built into them that filter out most of the Harmonics.

    Had Tesla invented the inverter, OK then name the car after him.

    But running DC from a bank of Capacittors, through a switching circuit and firing it off via HV IGBTs as a DC Square Wave isn't a AC Generator.

    Its a BIG Signal Generator. A Signal Generator ( Ive built a couple of them when I used to Hobby build ) is a electronic component.

    Not a Telsa invention and not even remotely a AC Generator.

    Try to run that square wave through a isolation transformer like a actual AC sinusoidal waveform for the purpose of Induction and your'e going to release " the magic smoke."
    Induction motors require an AC voltage source. Tesla invented the induction motor. Not that any of that has anything to do with why Elon named the company after Tesla.

    As for the rest, I'm not sure what you're getting at.

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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Mithros View Post
    Induction motors require an AC voltage source. Tesla invented the induction motor. Not that any of that has anything to do with why Elon named the company after Tesla.

    As for the rest, I'm not sure what you're getting at.
    Just trying to make clear that in terms of power generation that there is a distinct difference between a Signal Generator and a AC Generator.


    Personally I think they named the Car after Tesla because its sounded cooler than calling it the " Edison ".

    Thanks to 30 years of Electronics and Industrial controls experience I'm welll educated on the Technology that vehicle uses to get around.

    Its powered by DC and the primary debate between Edison and Tesla centered power generation and distribution.

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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Fenton View Post
    Just trying to make clear that in terms of power generation that there is a distinct difference between a Signal Generator and a AC Generator.


    Personally I think they named the Car after Tesla because its sounded cooler than calling it the " Edison ".

    Thanks to 30 years of Electronics and Industrial controls experience I'm welll educated on the Technology that vehicle uses to get around.

    Its powered by DC and the primary debate between Edison and Tesla centered power generation and distribution.
    The wires going into the motor don't care if the voltage was produced from an inverter, a gasoline powered generator, a solar panel, etc.. It's an AC powered induction motor. Just like a DC motor doesn't care if it's powered by a battery or an AC to DC power supply.

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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Mithros View Post
    The wires going into the motor don't care if the voltage was produced from an inverter, a gasoline powered generator, a solar panel, etc.. It's an AC powered induction motor. Just like a DC motor doesn't care if it's powered by a battery or an AC to DC power supply.


    Actually, motors have to be rated for inverter use.

    Run a 3 phase motor designed for continuous 60 hz operation on a inverter and it will overheat and trip the internal motor winding thermisrer.

    23 years ago when as a R & D and Test technician for a large manufacturer I had to attend a school on Siemens Variable Frequency Drives.

    We never addressed the operation in terms of A/C on a technical and Professional level because Inverters don't supply AC.

    They supply a DC Square wave.

    We needed to understand that distinction for troubleshooting and understanding the function of the drives.

    So for a layman you or anyone else can call that output AC and Tesla can get away with saying their supplying AC to a AC Motor.

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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Fenton View Post
    Actually, motors have to be rated for inverter use.

    Run a 3 phase motor designed for continuous 60 hz operation on a inverter and it will overheat and trip the internal motor winding thermisrer.

    23 years ago when as a R & D and Test technician for a large manufacturer I had to attend a school on Siemens Variable Frequency Drives.

    We never addressed the operation in terms of A/C on a technical and Professional level because Inverters don't supply AC.

    They supply a DC Square wave.

    We needed to understand that distinction for troubleshooting and understanding the function of the drives.

    So for a layman you or anyone else can call that output AC and Tesla can get away with saying their supplying AC to a AC Motor.
    I'm not trying to disagree with whatever training you received. But a square wave isn't DC. As Fourier proved, a time varying periodic signal can be decomposed into a number of harmonics. A square wave is essentially a combination of an infinite number of odd harmonics of the fundamental frequency. Here's an illustration of what happens when you start with a single sine wave and add specific odd harmonics.


    So a square wave is essentially a bunch of sine waves superimposed on each other, sort of like a bunch of different voices in a choir. So if you want to make a square wave look like "normal AC" you need to pass it though a low pass filter to get rid of the higher frequency components. This is sort of like getting rid of the altos, sopranos, and tenors, and keeping the bass.

    Anyway, point being.. inverters create AC and induction motors require AC.. (FYI I'm not quite a layman).

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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Mithros View Post
    I'm not trying to disagree with whatever training you received. But a square wave isn't DC. As Fourier proved, a time varying periodic signal can be decomposed into a number of harmonics. A square wave is essentially a combination of an infinite number of odd harmonics of the fundamental frequency. Here's an illustration of what happens when you start with a single sine wave and add specific odd harmonics.


    So a square wave is essentially a bunch of sine waves superimposed on each other, sort of like a bunch of different voices in a choir. So if you want to make a square wave look like "normal AC" you need to pass it though a low pass filter to get rid of the higher frequency components. This is sort of like getting rid of the altos, sopranos, and tenors, and keeping the bass.

    Anyway, point being.. inverters create AC and induction motors require AC.. (FYI I'm not quite a layman).

    I'm aware of all that but a DC oscillating output having some of the characteristics of a pure AC sinusoidal waveform doesn't make a Inverter a AC Generator.

    The output of a Oscillator or a inverter is simply a DC output in a repeating cycle with distinct characteristics from a sinusoidal waveform produced by a Generator.

    I can attests that there was always a HIGHLY dangerous 800 volt DC bus at the heart of all of the VFDs I use to troubleshoot.

    So thats 460 in, through a Full wave rectifier into a Bus and then into 3 isolated banks of very lethal Capacitors, through a Oscillator circuit and then fired out through HV IGBTs.

    It was manufactured.

    When I built my last Signal Generator I built it around the ICL8038 Wafeform generator chip and powered it with a linear DC power supply that contained positive and negative voltage regulators ( LM7812 and LM 7912 )

    I could even alter the positive and negative characteristics of that wave form and run 0-5 volt positive waveforms or 0-5 volt negative waveforms.

    So 115 into a step down trasformer before running the secondary through the Full wave rectifier, through Filter circuit and then into the DC voltage regulators

    There was NO House AC input on the back end of that signal generator.
    Last edited by Fenton; 10-09-14 at 03:21 PM.

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    Re: The 2014 Nobel Prize in Physics - Press Release

    Quote Originally Posted by Rainman05 View Post
    Really?
    For better blue LEDs?

    Are you kidding me.

    I mean, don't get me wrong, that's great and all, and better and more efficient powerful blue LEDs are always nice but the ones we have today are good enough. I mean, blue LEDs have been around for 20 years and they're good enough. I mean, shouldn't the Nobel prize go for like... big advances in a field instead of just improving something. There is no new massive groundbreaking technology involved in making these blue LEDs. They're just using a different coating. That's all.

    Ah well, good for them anyway.
    I didn't read the article, however I'm sure it has something to do with plasma rather than just a blue LED.

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