Three Phase Change over switches any negative effects?

#1 Jan 30th, 2012, 12:27
Join Date:
Jan 2012
Location:
Kerala
Posts:
1
  • 123blackjack is offline
#1
If we add 3 Phase Rotory Switches (3 nos) to change Phases ... Is there any adverse effects.

If we have a loose neutral or if neutral gets disconnect for some reason between the mains and having unbalanced load on phases will we have the chance for overvolting in any phase (440volts).

Will this happen only if i have the rotory phase shifting manual changer overs or will i be on the safer side if there is no change overs ?

Please help.....
#2 Jan 30th, 2012, 12:38
Join Date:
Sep 2005
Location:
India
Posts:
6,608
  • jyotirmoy is offline
#2
What exactly is your problem? I presume your load is single phase and you have three phases at your disposal. With a rotary switch you can choose the best phase and connect your load to it.
Improper neutral is a problem in many places. If your load is single phase you MUST need good neutral.
If you are distributing your single phase loads on three phases perfect balancing is impossible. So, again you need good neautral other wise severe voltage imbalance may occur. Many people make a good earth connection and connect the neutral to this earth but it has its own problems.
#3 Jan 30th, 2012, 12:39
Join Date:
Dec 2011
Location:
Vienna
Posts:
135
  • budget t is offline
#3
I wonder why you chose this site for technical queries !
#4 Jan 30th, 2012, 13:18
Join Date:
Nov 2003
Location:
melbourne, australia
Posts:
804
  • unclelach is offline
#4
There is already a thread covering these devices. See Similar Threads in right hand column.

These things may be an Indian specialty.
#5 Jan 30th, 2012, 13:49
Join Date:
Oct 2004
Location:
Chennai, India
Posts:
58,978
  • Nick-H is offline
#5
Compared to UK, the only other country I have lived in, it is certainly an Indian speciality. three-phase cables run in the street, but single phases only are run to domestic properties. We never meet more than 240V in our homes, and even that can be nasty!
Quote:
I wonder why you chose this site for technical queries !
Given that it is a part of living in India, it is useful. I don't think that it is possible to get 440v on one phase, because each rotary switch selects which phase a given set of circuits draws from, and not which circuits are fed by a particular phase.

Thus, you can connect more than one circuit to a phase but not more than one phase to a circuit.

That is my ignorant and naive understand. If an electrical engineer can explain it in simple terms, then I hope they do. Especially if I'm wrong!

One risk that I do know about is overloading a single phase. EG: a house has three powerful AC machines, each of which is connected to a different phase; two phases fail, and all three AC machines are connected to the remaining phase. This could burning out of fuses, or even of supply cables (especially if the voltage is low).

I have wondered if this is a danger of automatic phase switchers?
#6 Jan 30th, 2012, 16:51
Join Date:
Sep 2005
Location:
India
Posts:
6,608
  • jyotirmoy is offline
#6
Yes running all the gadgets on one phase in a house where wiring has been done assuming loads distributed on three phases poses danger. The neutral cable gets overheated along with the phase cable.
#7 Apr 5th, 2012, 22:47
Join Date:
May 2007
Location:
UK etc.
Posts:
2,059
  • a_f_d is offline
#7
I assume OP has three-phase to house and three rotary switches to switch each in-house load ('phase') to one of three incoming phases. (Check other threads I've posted stuff about this before) - - - my engineer told me "they are illegal - you must have one".
In the few months since we finally got 3-phase we have either had 3 phases or none, but it's early days.
Will you unbalance the load fro the transformer? - yes; and if all your neighbours do it - YES; Will it increase the chance of everything dropping out? Yes
Do you care .....

AndyD 8-)#
#8 Apr 5th, 2012, 23:48
Join Date:
Oct 2004
Location:
Chennai, India
Posts:
58,978
  • Nick-H is offline
#8
Quote:
"they are illegal - you must have one".


During bouts of unreliable supply we quite often loose one or two phases for a while. We switch the three loads to the working phase[s]. But we discipline ourselves as to how much we use. I would not dream of turning three AC machines on one phase: if our supply cable burns out, it is a major expense and nuisance to us (Been there, got the tee shirt).

I'd like to have an auto phase switcher but if it turned everything to one phase when I was roasting a chicken with three ACs on, a load in the washing machine, the water pump on, the shower pressure pump running, something in the microwave, then the toast would not be the only thing burning

Similar Threads

Title, Username, & Date Last Post Replies Views Forum
Why Germans are negative about India? Apr 21st, 2010 07:26 2 1046 Chai and Chat
Three-Phase Change-over switch Dec 31st, 2008 20:52 16 21744 Electronics in India
Now commencing phase II Sep 28th, 2007 21:27 9 1281 Chai and Chat
Negative volunteering experiences Nov 24th, 2006 15:24 4 1755 Volunteering and Charitable Causes in India


Posting Rules

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Forum Rules»
Trackbacks are Off
Pingbacks are Off
Refbacks are Off
Thread Tools
Display Modes

Search Engine Optimization by vBSEO 3.3.2
© IndiaMike.com 2014
Page Load Success