208/120V system 2-pole load a 2 phase or single phase?

[peterwire]

A 208Y/120V, 4 wire system has some loads with 3-pole CB which are 3 phase, 1 pole CB which are single phase. But what about the 2-pole CB loads, are these considered 2ph loads or single loads? which formula is applicable in this case: current= kW/(208V) or current=kW/(208*sqrt(2)*pf)? thnaks

 

[bwat]

But what about the 2-pole CB loads, are these considered 2ph loads or single loads?

Single phase 208V

 

[DrSparks]

A 208Y/120V, 4 wire system has some loads with 3-pole CB which are 3 phase, 1 pole CB which are single phase. But what about the 2-pole CB loads, are these considered 2ph loads or single loads? which formula is applicable in this case: current= kW/(208V) or current=kW/(208*sqrt(2)*pf)? thnaks

Yes they are single phase loads. And it's sqrt(3) not 2. You don't need that in your calculations for 1ph.

Sent from my SM-A326U using Tapatalk

 

[peterwire]

the voltage is line-to-line plus neutral. I would consider it 2-phase, thus, the formula to apply is the 2-ph formula (voltage line to line, sqrt (2)). why is that consider single phase?

 

[DrSparks]

the voltage is line-to-line plus neutral. I would consider it 2-phase, thus, the formula to apply is the 2-ph formula (voltage line to line, sqrt (2)). why is that consider single phase?

View attachment 2557426

It's not 2 phase. What device are you connecting that requires 2 phase and a neutral? Electric ranges and dryers require them but that's a multi wire branch circuit (MWBC). The internal circuits that are made inside the appliance are all single phase. For example: line to line for high setting on a burner... single phase. Line to neutral for the computer power supply... line to neutral... etc.

Sent from my SM-A326U using Tapatalk

 

[DrSparks]

To put it simply, you are using two phases of a 3 phase system. The phases are still 120 degrees out of phase. A 2 phase system has it's phases 90 degrees out of phase.

Sent from my SM-A326U using Tapatalk

 

[Besoeker3]

I'm glad that we don't have this complexity in UK and Europe.........................

 

[DrSparks]

I'm glad that we don't have this complexity in UK and Europe.........................

Are you saying you do not use 3 phase power in the UK? I find that highly unlikely my good friend.

Sent from my SM-A326U using Tapatalk

 

[Besoeker3]

Are you saying you do not use 3 phase power in the UK? I find that highly unlikely my good friend.

Sent from my SM-A326U using Tapatalk

Not at all. My comment was about the 208V and the 120V.
We just have 230V single phase and 400V three phase.

 

[DrSparks]

Not at all. My comment was about the 208V and the 120V.
We just have 230V single phase and 400V three phase.

Oh I see

Sent from my SM-A326U using Tapatalk

 

[don_resqcapt19]

the voltage is line-to-line plus neutral. I would consider it 2-phase, thus, the formula to apply is the 2-ph formula (voltage line to line, sqrt (2)). why is that consider single phase?

View attachment 2557426

The load is supplied by a single winding in the generator, the A - B winding, making it a single phase. The load needs to be supplied by multiple windings to make it something other than single phase.

 

[Jraef]

the voltage is line-to-line plus neutral. I would consider it 2-phase, thus, the formula to apply is the 2-ph formula (voltage line to line, sqrt (2)). why is that consider single phase?

View attachment 2557426

Although now very rare, "2-phase" is a real thing, but not what you show there.

However if you are from Europe, they call what you showed "2-phase", which can be confusing to those of us in North America, where we really do have it. We call it single phase.

 

[gar]

210802-2010 EDT

Two hots and one neutral from a 3 phase system are a 2 phase source. Any 2 wires from this source are a single phase source.

As soon as any source has more than two wires, then it has the possibility of being a multiple phase source.

.

 

[DrSparks]

The load is supplied by a single winding in the generator, the A - B winding, making it a single phase. The load needs to be supplied by multiple windings to make it something other than single phase.

Or a single coil in a transformer

Sent from my SM-A326U using Tapatalk

 

[jim dungar]

To put it simply, you are using two phases of a 3 phase system.

You are using 2 phase conductors.

I believe a source of confusion is caused by people using the simple word 'phase' as a noun instead of as an adjective.

 

[DrSparks]

210802-2010 EDT

Two hots and one neutral from a 3 phase system are a 2 phase source. Any 2 wires from this source are a single phase source.

As soon as any source has more than two wires, then it has the possibility of being a multiple phase source.

.

What publication are you referring to? Again, what device in a home, commercial establishment, or modern industry would utilize 2 phase current?

If you use 2 phases of a 3 phases system and hook it up to a scope, just how many sine waves are you going to see, hmm?

Sent from my SM-A326U using Tapatalk

 

[DrSparks]

You are using 2 phase conductors.

I believe a source of confusion is caused by people using the simple word 'phase' as a noun instead of as an adjective.

Phase is a noun.

It is used to refer to a conductor carrying the phase current of a polyphase system. It could also refer to the phase of current or voltage in a formula. Either way it's a noun.

Sent from my SM-A326U using Tapatalk

 

[jim dungar]

Phase is a noun.

Sent from my SM-A326U using Tapatalk

Not when it is used to describe a single conductor as in 'for a 2 wire circuit you need to pull a phase and neutral'.

 

[DrSparks]

Not when it is used to describe a single conductor as in 'for a 2 wire circuit you need to pull a phase and neutral'.

Of course it is.

If you said, for example, you need to pull a blue phase, then blue would be the adjective and phase would be the noun.

Sent from my SM-A326U using Tapatalk

 

[gar]

210802-2051 EDT

DrSparks:

Take a two channel scope ( supply it from an isolation transformer to avoid a grounding problem thru the scope ) and connect the scope chassis to the power system neutral wire for the electrical reference point.

Connect channel A scope probe to one of the hot phase conductors. Get scope sync from channel A. Connect channel B to the second phase conductor.

Displayed on the scope are two sine waves with a phase difference between them of about 120 degrees.

.