3 phase system in house is more cheaper than single phase system in terms of current consumption. is it true?

Question

how does tht work...

Answer 1

Yep, it would be more efficient than single phase. But not practical for home purposes.

Nikola Tesla invented our AC polyphase electrical system, as well as motors that make use of it. His motors don't actually run directly on "current" or even "voltage" in the sense that DC motors do --- they merely chase oscillating currents in the AC system. It's really much cleaner and more efficient . You probably have these Tesla "inductive" motors around the house -- in your washing machine, dryer, swamp cooler. They last a long time. Since they're small motors with low output requirements, single-phase is usually sufficient. Big industrial motors can make use of an added phase of oscillation, so industrial areas are usually wired to handle the extra power line.

A really great intro to how the grid is wired to your house, as well as a ton of fun electricity stuff can be found at:
http://amasci.com/ele-edu.html

Great article in there about why various plugs (polarized, grounded, etc.) have been designed. Great site for kids, too...

Answer 2

Under FAULT conditions, Neutral currents can be greater than Phase currents. The Neutral current at the supply side of the Neutralizing connection at the supply point, (that joins the Neutrals and customer main grounding system), not only CAN have higher than the Phase conductor current, but the Neutral can have current even when there is NO Phase current. How can this be? The most extreme case of high Neutral currents occours and more seriously may remain undetected, when the supply Neutral to nearby installation 2 breaks or goes open circuit. Assume 20A Phase wire current at this installation, 20A to and through load back through Neutral to Neutralizing connection, as supply Neutral is open, the 20A tries to get back to supply transformer via Installation 2's grounding electrode. Note no breakers or out-of-balance current detectors trip, or fuses blow. The load drawing the 20A continues to work, perfectly! But Installation 1's Grounding electrode is nearby with its connection to a working Neutral, so most of the 20A is likely to take this path. In most cases, adjacent domestic grounds are very very adjacent. Installation 1's supply may have zero phase current, but about say 15A Neutral current via the earth from installation 2. In any case the supply Neutral current will far exceed the Phase current at installation 1. For a single phase as stated, under no fault conditions the supply Phase and Neutral currents should be equal. Note that part of the normal ground fault path is from the neutralizing connection to ground electrode, is reversed here as the path to Neutral is from ground to neutralizing connection. Similarly, a PART of any ground fault leakage current in Installation 2, or other nearby installations, can return via installation1's ground electrode to Neutralizing connection, and supply Neutral. This also leads to the Neutral current being greater than the Phase current in installation 1.

Answer 3

3 phase is only for industrial equipment. It would be very expensive to run 3 phase into your house. Most household appliances run off of single.

Answer 4

Nope. Everything you have is made for single phase. (really dual phase, but everybody calls it single just to confuse things) You can use two of the three phases to run your stuff, but the voltages will be off, and you won't have a neutral so you could electrocute yourself. Since you had to ask this question, it's a pretty good bet you shouldn't be fooling with stuff that can kill you.

Answer 5

Power consumption would be about the same.It would only be cheaper if electricity charges is cheaper for 3 phase system.

Answer 6

if your running industrial motors, but it is expensive to have three phase run into your house and regular appliances would only run on one of the phases any how.