Weak Arc on Lincoln 225 ac

[Industrial Toys]

So true. Yet who wants to devote a large amount of time to a problem, when it's possible you aren't getting accurate data. Never forget some guy saying his tractor wouldn't start or something, and LATER found out the thing had been submerged for some time!

Almost needs to be an FAQ for beginners "Tractor Won't start" How many thousand threads suggesting checking your battery connections are there going to be?

 

[user.69169]

Last 2Ø plant in US was in Philly serving part of Navy Yard.

Term 2Ø continues to be used in some areas where Wildcat (open Delta) 3Ø is provided to customers from 2 transformers tied to 2 Primary phases. Sort of entertaining on storm restorations to see a lineman in bucket wid his laptop making connections.

 

[grsthegreat]

Not again.....
Anyways, the only appliances in most newer residential houses that have a neutral used with 240 volts are the range and dryer. Water heaters, heat pumps and ac units, elect furnaces, well pumps dont require a neutral. I cant think of any 240 Appliance that would sit in a normal shop that would require a neutral.....unless you count using an old stove as an oven to bake powder coat.....but then again that oven would probably be so old as not to have a neutral.

 

[Fuddy1952]

I worked with test equipment 43 years as a technician before retiring over 6 years ago.
This 11 minute video gives an easy to understand explanation of residential household current.

Using an Oscilloscope to Understand 120 VAC Split phase Household Power Supplies - YouTube

Your pole transformer is supplied with high voltage 2.4kV+) primary in, secondary is center tapped. So 3 wires, center (ground/neutral) then 240v (rms) across outer two.
From EACH of the two to center neutral is half or 120v rms.
An oscilloscope shows time (horizontal or x axis) vs voltage (vertical or y axis).
Video shows from neutral to each outer lead is 120v, with each one 180 degrees out of phase with the other.
To get 240v has to be across two outer leads.

 

[jaxs]

I worked with test equipment 43 years as a technician before retiring over 6 years ago.
This 11 minute video gives an easy to understand explanation of residential household current.

Using an Oscilloscope to Understand 120 VAC Split phase Household Power Supplies - YouTube

Your pole transformer is supplied with high voltage 2.4kV+) primary in, secondary is center tapped. So 3 wires, center (ground/neutral) then 240v (rms) across outer two.
From EACH of the two to center neutral is half or 120v rms.
An oscilloscope shows time (horizontal or x axis) vs voltage (vertical or y axis).
Video shows from neutral to each outer lead is 120v, with each one 180 degrees out of phase with the other.
To get 240v has to be across two outer leads.

Opps,now you have gone and steped in it.

We have had this argument before. They are not out of phase. They are simply different taps (different potential) off a single phase transformer. No such thing as two phase household service. Saying that the two 120 legs are in different phase, would suggest some kind of two phase service.

Anyone who needs to understand household 120/240 service should investigate how a transformer works.

Think of it as with DC and batteries. You have four 6 volt batteries in series. Gives you 48 volts. Now you connect the center connection between two batteries to ground. Now you will get 24 volts to ground from the farthest battery one way and the sme from the farthest battery the other way, AND 48 volts between the two. This is EXACTLY the arrangment with the transformer feeding your house. Center tap goes to neutral/ground. Nothing at all about phase! It's about voltage/potential off the transformer windings.

I'll just take my popcorn back over to the tall wall of electrical and watch. :laughing:

 

[Industrial Toys]

Sorry. Utter non sense. I can take a scope and make it look like anything I want for starters. You tell me, how you get 180 degree phase shift in a transformer one end of the winding to the other? That would be interesting. 240 volt center tapped transformer with one copper secondary winding connected end to end, tapped and connected to ground in the middle. Something about your waveforms is confusing you terribly about how this works.

Funny. I had to educate a industrial electrician (for his whole life) on inductance. With his high impedence digital meter he couldn't understand why he was still getting readings on disconnected conductors, running in a conduit with operating conductors. So no, length of time in, don't impress me much.

So by your notion, if a 240 volt secondary transformer was tapped at say the previous 40/200 volts I mentioned, neutral and ground connected at the connection point, what would the phase relationship be?

Oh and I suggested this before, but if the phase of the one leg was 180 degrees out of phase with the other, I think they would cancel each other out and you would get no potential across them at all..

 

[Topzide]

Amazing to me that a welding question has morphed into an electrical phase discussion! I'll have some popcorn too and sit back for the show.

 

[Industrial Toys]

Maybe, just maybe the confusion arises precicely out of what some call it. Split phase. Yes, it's a one phase circuit that is "split" (center tapped to neutral). The phase (timing) isn't split in two. If that makes any sense.

And for whatever it's worth, I have no engineering degree but I did earn a living money for years using an osciloscope. Still have but rarely use one.

 

[the old grind]

Maybe, just maybe the confusion arises precicely out of what some call it. Split phase. Yes, it's a one phase circuit that is "split" (center tapped to neutral). The phase (timing) isn't split in two. If that makes any sense. ....

It does as long as I think the two legs are 180^ apart and a neutral center tap is just a node in 240v use.

btw, IIRC 2-Ph is std in Europe or Britain somewhere, only some commercial use stateside..

 

[Industrial Toys]

WEll then maybe I can ask you. How do you get different phase relationship across the two legs (really only one winding with a center tap), of a fixed transformer? It's not a rotating field as in a generator.

Came across this. How can they say in one instance split phase and then say it is (in phase)?

"Single phase power systems are defined by having an AC source with only one voltage waveform. A split-phase power system is one with multiple (in-phase) AC voltage sources connected in series, delivering power to loads at more than one voltage, with more than two wires."