For example, my supply is 415 volts RMS (line-line). So if I multiple it by sqrt2 to get the peak voltage. That’s a phase voltage, I believe. If I rectify this supply and get an output voltage waveform, it’s the peak of this voltage waveform a line to line voltage or a phase voltage?
\$\begingroup\$
\$\endgroup\$
6
-
1\$\begingroup\$ It's more likely that 415 is a line voltage. \$\endgroup\$– Andy akaJun 7, 2020 at 16:23
-
\$\begingroup\$ @Andyaka i meant line voltage, my bad. then what about the rectified voltage? Is it a phase voltage? \$\endgroup\$– Kwaku E. BineyJun 7, 2020 at 16:26
-
\$\begingroup\$ Do you know how to formally accept a good answer to any of the questions you receive? Did you know that accepting a good answer is a mark of respect? Of course you don't have to do this. \$\endgroup\$– Andy akaJun 7, 2020 at 16:28
-
\$\begingroup\$ @Andyaka ?? What do you mean \$\endgroup\$– Kwaku E. BineyJun 7, 2020 at 16:29
-
\$\begingroup\$ Have you ever seen the green "tick" mark alongside answers to other answers - this means that they are recognized as being the best answer as judged by the questioner. It's something that you might want to get in the habit of doing to any question you have raised that has got a good answer. If you don't get an understandable answer then you should raise a comment with the person making the answer until it becomes a good answer. \$\endgroup\$– Andy akaJun 7, 2020 at 16:32
|
Show 1 more comment
3 Answers
\$\begingroup\$
\$\endgroup\$
1
Specified 3-phase voltage V is the RMS value of the line voltage.
After full wave bridge rectification, the average DC voltage would be (3 x √3 x V)/π = V x 1.654.
For 3-phase 415V, the average DC voltage would be 686V.
\$\begingroup\$
\$\endgroup\$
Typically "Y" or "Wye" or "Star" Vac= Phase to Neutral to end-user
Delta has no Neutral with 3 wires so Vac = Phase to Phase or "line to line"
But then if you knew how to learn with simple keywords, you could have found this answer on your own. https://blog.teledynelecroy.com/2018/03/more-basics-of-three-phase-ac.html
\$\begingroup\$
\$\endgroup\$
1
If you rectify 3-phase as 3 wires (delta), you get peak phase-to-phase voltage assuming no load.
If you rectify 3-phase as 4 wires (star), you get peak voltage phase-to-ground assuming no load.
With load your voltage will be smaller and mostly depend on a capacitor. Assuming capacitor reactive power (capacitor stored energy multiplied by frequency) matches your load power, drop will be about 10% voltage and power factor of 0.6.
-
2\$\begingroup\$ no, if you rectify 3phase supply that is sourced via a star arrangement, you get peak line-line since at any moment in time one phase conducts on the positive cycle and another conducts on the negative \$\endgroup\$– user16222Jun 7, 2020 at 17:00