Timeline for Why three-phase power? Why not a higher number of phases?
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 14, 2015 at 9:58 | comment | added | Hugoagogo | Thanks I decided on this answer as it described, a good number of possible reasons where more phases could be required. Also @Court Ammons, answer made me realize that mathematically there is no improvement in motor smoothness, 3 is already an optimal case (wolframalpha.com/input/…). | |
| Aug 14, 2015 at 9:52 | vote | accept | Hugoagogo | ||
| Aug 13, 2015 at 22:36 | comment | added | Olin Lathrop | Your first statement is incorrect. 2 phases 90 degrees apart can also run a motor in a predictable direction and with constant power. Two phase quadrature power is also not inherently less efficient to generate. There are of course other reasons 3 phase power is used, but your answer misses those points. | |
| S Aug 12, 2015 at 19:16 | history | suggested | David Richerby | CC BY-SA 3.0 | Plasma's answer isn't "above" for everyone |
| Aug 12, 2015 at 18:59 | review | Suggested edits | |||
| S Aug 12, 2015 at 19:16 | |||||
| Aug 12, 2015 at 13:20 | comment | added | R Drast | Those are also common transformers for feeding a large VFD with regenerative capabilities. For regen capabilities though, one winding is generally provides about a 5% step up to the incoming line to allow for dumping excess power, | |
| Aug 12, 2015 at 11:51 | comment | added | Li-aung Yip | Re rectifiers with lots of phases - for big equipment (2,280 kW hoists) I've mostly seen the phases being derived from a multi-winding transformer, which is very efficient. Using a delta-delta-star (Dd0y5) transformer will turn three phases into six phases. Most of the time when I've seen a motor-generator set it's to turn AC into DC. | |
| Aug 12, 2015 at 10:43 | history | answered | R Drast | CC BY-SA 3.0 |