How to figure 3 phase voltage drop
How to figure 3 phase voltage drop
(OP)
When figuring 3 phase voltage drop do you use the distance to the load or 2 times that?
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
Download nowINTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
How to figure 3 phase voltage drop
|
RE: How to figure 3 phase voltage drop
In single-phase circuits, with the neutral conductor size equal to the phase conductor, you'd double the distance to account for the total voltage drop (phase plus neutral).
RE: How to figure 3 phase voltage drop
For example, if you have 0.2 ohms resistance in each phase condutor of a 208/120V, 3-phase system and 15A of load. The VD per line will be 15A*0.2 ohm=3V, The percentage voltage drop will be 3V/120V=.025 or 2.5%. Line to line VD will be 5.2V, still 2.5% of 208V.
Same is true, it were a delta system, even if there is no physical neutral. The calcs are still done on per phase basis, using phase voltage=line voltage/1.732.
(For purists: Above example ignores reactance for simplicity.)
RE: How to figure 3 phase voltage drop
Once you read the correct value from the table, you multiply by twice the distance in 1 phase and simply by the distance in 3 phase.
You should be aware enough to know that as you have more applianced branched in parallel on the same circuit, you need to calculate the voltage drop chunk by chunk; other easier methods exist of course but should be a nice exercise.
Also, the impedance values are given in some catalogs for cos phi = 0.8 as well as for cos phi = 1, which is the worst case (highest resistance).
RE: How to figure 3 phase voltage drop
RE: How to figure 3 phase voltage drop
RE: How to figure 3 phase voltage drop
http://www.aberdare.co.za/
http://www.eurocabos.pt/ (reseller)
http://www.cabelte.pt/
http://www.generalcablecelcat.com/index.html
You can also find prices on these websites.