[Boatanchors] Basic electricity question

[WA5CAB at cs.com]

Gary,

Well, I think you were speaking theoretically and I was speaking from 
practical experience (and Code requirements).  A perfectly balanced three-phase 
system even if Wye connected would have no current flowing in the neutral and you 
could save 20% on copper costs plus nearly that much on conduit diameter costs 
and dispense with the neutral.  There was for example no neutral on our 
compressor pad because it was Delta to Delta and the controls were on another 
system.  But in most practical situations, commercial three phase end-user systems 
are a mix of single and three phase loads.  So you usually do need the neutral. 
 If you don't have it, you may end up with the same situation as happens if 
you lose the neutral in a 120/240 volt single phase system.  The side (or 
phase) with the heavier load will be starved for voltage and the side (or phases) 
with the lighter load(s) will get real bright (for a little while).  Been 
there, done that, we couldn't afford tee-shirts because of the cost of the 
equipment destroyed.  :-)



In a message dated 1/13/2005 9:33:36 PM Central Standard Time, 
garyschafer at comcast.net writes: 
> Hi Robert,
> 
> I thought I was covering all my bases. I did say "no neutral required". :>)
> But, if a neutral is used in a Y 3 phase then the part of the load that 
> uses the neutral is not a 3 phase load but a single phase load. :>)
> 
> 73
> Gary  K4FMX
> 

Robert Downs - Houston
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