PLEASE!!!!! I need electrical help.

[GeorgeTelford]

Hi Larwyn

What I said was that in a series circuit, total current is equal to current in any other part of the circuit. This is true at zero amps just as much as it is at a thousand amps. With the switch open you would measure zero amps in all parts of the circuit.....

]

Do note the highlighted points in the above quote

I had considered that point, however.......

If there is no circuit, then there is no current to measure, ie you are not actually measuring anything, for example let us say a building stands 150 feet high, but if there is no building in front of you, you cannot say that this building is zero feet high (do you see? there is no building there to measure, same with the amperage)

PS zero amps is impossible in any circuit

[Larwyn]

Hi Larwyn

What I said was that in a series circuit, total current is equal to current in any other part of the circuit. This is true at zero amps just as much as it is at a thousand amps. With the switch open you would measure zero amps in all parts of the circuit.....

]

Do note the highlighted points in the above quote

I had considered that point, however.......

If there is no circuit, then there is no current to measure, ie you are not actually measuring anything, for example let us say a building stands 150 feet high, but if there is no building in front of you, you cannot say that this building is zero feet high (do you see? there is no building there to measure, same with the amperage)

PS zero amps is impossible in any circuit

I'll agree that you are right, if the circuit is open there are no amps to measure. However in my line of work, zero amps is a valuable number to read prior to working on the 345,000 Volt equipment in the switchyard. In practice this is "read" by observing that the air break switches are open..............

I do see your point.

[Chuck Craven]

Well George! I have been an electrocution for 40 years and when I went to school it was called three wires two phase power!
It is now called split phase power. But most power companies in the USA still call it two phase. Habits are hard to change!

Take a look at this. May be it will help. I took it off the web!

Two phase
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Two-phase electrical power was an early 20th century polyphase alternating current electric power distribution system. Two circuits, or "phases", were used, with voltages 90 electrical degrees apart in time. Usually circuits used four wires, two for each phase. Less frequently, three wires were used, with a common wire with a larger-diameter conductor. The generators at Niagara Falls installed in 1895 were the largest generators in the world at the time and were two-phase machines. Some early two-phase generators had two complete rotor and field assemblies, mechanically shifted by 90 mechanical degrees to provide two-phase power.

The advantage of two-phase electrical power was that it allowed for simple, self-starting electric motors. In the early days of electrical engineering, it was easier to analyze and design two-phase systems where the phases were completely separated, since this avoided the need for the effect of unbalanced loads. It was not until the invention of symmetrical components that three-phase power systems had a convenient mathematical tool for describing unbalanced load cases. The revolving magnetic field produced with a two-phase system allowed electric motors to provide torque from zero motor speed, which was not possible with a single-phase induction motor (without extra starting means). Induction motors designed for two-phase operation use the same winding configuration as *capacitor start single-phase motors.

Three-phase electric power requires less conductor mass for the same voltage and overall amount of power. It has all but replaced two-phase power for commercial distribution of electrical energy, but two-phase circuits are still found in certain control systems.

Two-phase power can be derived from a three-phase source using two transformers in a Scott connection. One transformer primary is connected across two phases of the supply. The second transformer is connected to a center-tap of the first transformer, and is wound for 86.6% of the phase-to-phase voltage on the 3-phase system. The secondaries of the transformers will have two phases 90 degrees apart in time, and a balanced two-phase load will be evenly balanced over the three supply phases.

Three-wire, 120/240 volt single phase power used in the USA and Canada is sometimes incorrectly called "two-phase". The proper term is split phase or 3-wire single-phase.

See also
Polyphase system

References
Terrell Croft and Wilford Summers (ed), American Electricans' Handbook, Eleventh Edition, McGraw Hill, New York (1987) ISBN 0070139326
Donald G. Fink and H. Wayne Beaty, Standard Handbook for Electrical Engineers, Eleventh Edition,McGraw-Hill, New York, 1978, ISBN 007020974X
Edwin J. Houston and Arthur Kennelly, Recent Types of Dynamo-Electric Machinery, copyright American Technical Book Company 1897, published by P.F. Collier and Sons New York, 1902
Retrieved from "http://en.wikipedia.org/wiki/Two_phase"
Categories: Electricity distribution

[GeorgeTelford]

Hi Chuck

I think you are mixing me up with someone else (probably Rev Ken)

I believe in the phased power and understand one, two and three phase power, its RevKen saying it doesnt exist and that no current goes back via the neutral wire.

[Chuck Craven]

Sorry Gorge! I sent you my post as a PM hit the wrong button.

We all went in to left field and left Scott standing all confused! Probably made him even more confused!

Scott this is how to figure out the size of the circuit you will need for your camper.

The light bulb and switch:
The switch does not draw any power. The light bulb is ratted in watts you need amps. To convert watts to amps: divide watts by the voltage in use.
Example: 100 watt bulb 110 v.ac = 0.9 amps.
Light bulbs and frying pans are resistive loads and that is the total current the devices will use.

Your AC and refrigerator have motors in them and have an inrush current that may or may not be on the ratting plat. There should be a running current and maybe a starting current ratting. If there is no starting current ratting you can do a guess to the starting current by this method.

Take the running current and multiply it by 0.7 then add that to the running current that gives you the starting current. It will be close to the real starting current.
Assuming the AC runs off of 110 v ac!
Example: AC running current 6.2 amps starting current will be11 amps.
Ref running current 4.6 amps starting current will be 8 amps

To figure the amperage needed you just have to add all the currents like this.
Light bulb = 0.9 amps
AC start = 11 amps
Ref start = 8 amps
Total is = 18.9

So a 20 amp supply will work with every thing turned on if you plug in to the power pole at the campground.
The running current will be 12 amps, this will give you 8 amps lift over for TV and other appliances plugged in to the duplex outlet.

If you are not using the AC you then can use things like a frying pan at 1000 watts and a coffee maker at 700 watts. You just have to be careful not to use more than the 20 amp supplied by the power pole.

I hope I didn’t make thing even more confusing.
Chuck

[Rev. Ken]

[quote="GeorgeTelford"]Rev Ken said

there is no such thing as two phase it is still single phase.

An electrician who doesnt believe in electricity phases?

And to correct what someone else said. While the black wire does carry the curent to the outlet the white does not carry it back.

This is totally and utterly wrong in every respect


George,
you are totaly right and I made a mistake with what i wrote.
While the black does carry the current down what I forgot was that it goes thru the load and then back. Thank you for pointing that out.
I guess I shouldn't have tried to answer while on pain killers.
As for the phases I looked in ever book I have and could find no reference to 2 phase power, The discription that was posted does seem to suggest that it is an old way of doing things. Since I don't work with anything above 277v 3-phase I did not know about it.
Thank you for the correction.

[GeorgeTelford]

Hi Ken

No Problem, I must admit, I thought you were having us on ( or that it was some kind of elaborate wind up )

Hope the pain clears up soon ( and hence the need for pain killers )

Regards

George

PS its apreciated that you came back to clear this up, takes some Mojo to admit mistakes/error's