two phase or single phase

[jorge copas]

are two hot lines out of a 3 phase system called 2 phase?

any info will be apreciated

 

[iwire]

In my opinion no, the common usage would call two legs of three phase single phase.

There is another old system that was called two phase.

That said there are some here that will call two legs of a three phase system 'two phase' but I think they just do so for the pleasure of disagreeing with the masses and arguing.

 

[infinity]

I agree with Bob. If I remember correctly, the old 2 phase systems had their phases 90 degrees out of phase.

 

[sparky59]

It is two phases .....but not two-phase.

 

[e150club]

the way i was taught was 3ph is a,b,c, 1,2,3, or blu,blk,red. x,y,z. 208 or 220 2 wire is just that 2 wire 208 or 220v single phase with a neut.for 104/110v no such thing as two phase then u could say 104 110 115 220 230 240 440 460 480 most of these # are obsolete.

 

[Charles R. Miller]

Bob and Trevor are correct. The phases on a two-phase system are 90 degrees apart. A two-phase system has four ungrounded (hot) conductors and one neutral.
Charles

 

[brian john]

I am not sure I follow e150's post 104/110?


From the Mike Holt News Letter Archieve

http://www.mikeholt.com/newsletters.php?action=display&letterID=53

 

[boboelectric]

2 PHASE might still be in use in the Philly area. A 5 wire thing,as i remember.

Bob O.84,Pa.15330

 

[e150club]

the reason i put the differnt #s is everyone uses 120 240v as normal voltages. on long island ive seen voltage drop lower then 208 under high demand. i know that is off the ? about phases sorry.

 

[brian john]

2 PHASE might still be in use in the Philly area. A 5 wire thing,as i remember.

Bob:

Only place I ever saw this was downtown Philly, building was an OLD warehouse or manufacturing facility, converted to office building. I was told this was 2-phase 5-wire.

 

[eric1973]

Calculating Neutral Amps

Calculating Neutral Amps

In a single phase panel a branch circuit using the same neutral, the neutral amperage is the combined amperage of both circuits. In a three phase panel, three circuits sharing the same neutral, is the neutral carrying all of the combined amps of the three circuits?

 

[jorge copas]

2 phase or single phase?

2 phase or single phase?

thanks guys all your answers will be apreciated!

 

[Smart $]

In a single phase panel a branch circuit using the same neutral, the neutral amperage is the combined amperage of both circuits. In a three phase panel, three circuits sharing the same neutral, is the neutral carrying all of the combined amps of the three circuits?

In all cases, the neutral carries the combined currents. However, when circuits are powered by different legs, the currents are vectorially added where they splice into the neutral. In algebraic form:

Neutral current for 1? mwbc is In = |Ia-Ib|
Neutral current for 3? mwbc is In = √(Ia? + Ib? + Ic? - Ia?Ib ? Ib?Ic ? Ia?Ic)​

The above formulas do not account for harmonics, i.e. non-linear currents introduced by loads.