240 V return path

[rattus]

Single Phase Argument:

Single Phase Argument:

The confusing part is that the former is 1 winding yet they call it A phase and B phase this is because we measure from ground of a center tap so like 2 batterys in series we get a pos voltage to one side and a negative voltage to the other side this is caused by reversing the polarity of the test leads when we measure to ground it is really only one winding yet we say it has 2 different phases. This is why when the 240 volt load is balanced there is no current on the neutral it is the same winding anyway this is all a zero sum game we play.

Strictly speaking, Line 1 and Line 2 are not phases. the separation is 180 degrees. The separation in a true 2-phase system is 90 degrees, and few if any such systems are in operation today.

 

[rattus]

Why so?

Why so?

Kirchoffs law reminded me of a problem I was posed years ago:

Imagine a drawn cube and each of the 12 straight lines forming that cube were a 1 ohm resistor the points of convergence were connections. What is resistance between any two diagonally opposite sides?

You can intuit that value but cannot prove it withiut Kirchoffs Law.
Answers please!.

True, you cannot solve this problem in the conventional way, but I don't see where it requires Kirchoff. Explain please.

 

[megloff11x]

How did you hook it up and was the heater active while measuring? If it was heating or stopping heating, the current may have changed between your hook ups.

A more plausible explanation is if you are measuring low current (<5-10A) many of these clamp on amp meters don't read too well - not enough field strength to excite them.

Read the fine print in the manual - the part they don't tell you until your check has cleared.

One trick is to make a 10-20 loop wire and wire nut it in series (this entails surgery on the wiring which defeats the purpose of a clamp-on as non-invasive) with your wire. Then the probe will read 10-20x the current, just like it was a transformer.

I've had to do this on low HP 480V VFD run motors before.

A 240V center grounded home type system will have the center grounded (and becoming the neutral) so it's 120V either end to middle (neutral) but still 240V end to end. You shouldn't be losing any current. Likely it's a limitation of the measuring equipment.

Matt

 

[quogueelectric]

phasing

phasing

Strictly speaking, Line 1 and Line 2 are not phases. the separation is 180 degrees. The separation in a true 2-phase system is 90 degrees, and few if any such systems are in operation today.

If you read what I was trying to say there is no 2nd phase on this xformer it is the same windind there is no 180 degrees you are just switching the meter leads around 180 degrees now do you understand?????

 

[rattus]

More than you know:

More than you know:

If you read what I was trying to say there is no 2nd phase on this xformer it is the same windind there is no 180 degrees you are just switching the meter leads around 180 degrees now do you understand?????

I understand more than you think. I am simply saying it is incorrect to call the two legs of a 120V/240V service "phases". And, if we measure these two voltages with respect to the neutral as is commonly done, there is indeed a 180 degree phase difference between them. Nevertheless, it is still a single phase service.

I think we are saying about the same thing.