Harmonics
- Thread starter Neelesh
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scott thompson
Senior Member
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- Anaheim, California
Re: Harmonics
I thought Even Order Harmonic Distortion (2nd, 4th, 6th...) was an Audio issue...???
: )
:roll:
Triplen (?3 of fundamental Hz and equal increments thereof) results in nastyness within the common conductor of a 4 wire 3? Wye's multiwire branch circuitry, when THD is >20% per Line (worst cases found at 33% +).
These Hz would fall at crossings of 60Hz ? 3, 180Hz ? 3 and 360Hz ? 3, and every third multiple afterwards.
The 1st / 3rd Harmonic point - at 180HZ, is where 60Hz ? 3 and 180HZ combine. Others combine in a similar fashion throughout the spread.
Not sure if even order Harmonics will exist on an AC, or if Odd order Harmonics will exist in an Audio (Sound) wave. If anything, they will be of very low amplitude.
Just my 2?...
Scott35
I thought Even Order Harmonic Distortion (2nd, 4th, 6th...) was an Audio issue...???
: )
:roll: Triplen (?3 of fundamental Hz and equal increments thereof) results in nastyness within the common conductor of a 4 wire 3? Wye's multiwire branch circuitry, when THD is >20% per Line (worst cases found at 33% +).
These Hz would fall at crossings of 60Hz ? 3, 180Hz ? 3 and 360Hz ? 3, and every third multiple afterwards.
The 1st / 3rd Harmonic point - at 180HZ, is where 60Hz ? 3 and 180HZ combine. Others combine in a similar fashion throughout the spread.
Not sure if even order Harmonics will exist on an AC, or if Odd order Harmonics will exist in an Audio (Sound) wave. If anything, they will be of very low amplitude.
Just my 2?...
Scott35
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Harmonics
Here's a white paper with a somewhat good graphic
http://www.schneider-electric.ca/www/en/products/busway/0104ED9501R896.pdf
Here's a white paper with a somewhat good graphic
http://www.schneider-electric.ca/www/en/products/busway/0104ED9501R896.pdf
Re: Harmonics
A circuit with a half wave rectifier will produce even numbered harmonics.
Even number harmonics are 180 degrees out of phase, which cancels any created current and voltage.
Projector lamps operate on a half wave diode, the circuit is rich with even number harmonics.
A circuit with a half wave rectifier will produce even numbered harmonics.
Even number harmonics are 180 degrees out of phase, which cancels any created current and voltage.
Projector lamps operate on a half wave diode, the circuit is rich with even number harmonics.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Harmonics
You've got to draw out the three phase time/current sin wave at 60 Hz and 120 Hz and 240 Hz, and see how the values at different time instants of the drawing add to zero or not depending on if it's even or odd multiples of 60hz.
You've got to draw out the three phase time/current sin wave at 60 Hz and 120 Hz and 240 Hz, and see how the values at different time instants of the drawing add to zero or not
depending on if it's even or odd multiples of 60hz.Ed MacLaren
Senior Member
Re: Harmonics
Neelesh,
Here is a little sketch comparing, for example, third harmonic currents versus even (120 hz) harmonic currents in a three phase system.
The 120 hz harmonic currents of the three phases are not "in phase" with each other. (bottom sketch)
Ed
Neelesh,
Here is a little sketch comparing, for example, third harmonic currents versus even (120 hz) harmonic currents in a three phase system.
The 120 hz harmonic currents of the three phases are not "in phase" with each other. (bottom sketch)
Ed
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Harmonics
Ed,
Perfect graphic.
I was just trying to create something similar on excel, but you captured the concept perfect.
What do you use to create that with such symmetry? Impossible to do free hand
Ed,
Perfect graphic.
I was just trying to create something similar on excel, but you captured the concept perfect.
What do you use to create that with such symmetry? Impossible to do free hand
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