220v conversion question

Try it. You *will* notice the difference.

Reply to
krw
Loading thread data ...

No, each of the wires in a 220v circuit is carrying the same current, one carries it in, one carries it out, just like with 110.

Reply to
J. Clarke

But you are. By your saying that it's perfectly safe (it isn't) and just the "committies" doing something just to do _something_, you're telling anyone here who will listen to violate code.

Not always used, nor useful.

So you think it's alright to tell people to perform unsafe acts? They're "safe enough", even though they clearly are not, in the eyes of thoese with jurisdiction over such things.

So your lousy experience in some unnamed committee trumps all safety rules?

Ah, the disclaimer, where you tell people that its not your fault when their kid gets electrocuted.

As much as you may think so, fire/electrical codes are not there so "others can make their own determination".

Reply to
keithw86

That would suggest a direction to the current flow, and with AC we know that isn't the case.

Reply to
Robatoy

I (OP) noticed a difference.

Reply to
DLB

It was a coloring book explanation.

Reply to
Leon

The resistance of the motor changes when rewired for 240V.

Chris

Reply to
Chris Friesen

As I mentioned in my first email, if it makes that much difference then it's likely the motor itself was not operating optimally at 120V.

Aside from supply losses which have been discussed extensively :) in this thread, there's no inherent reason why a motor would operate more efficiently at higher voltage.

Chris

Reply to
Chris Friesen

OP: You have gotten a little good advice and a whole lot of very bad advice. You problem is figuring out which is which. If I someday have a death wish, I'll have to remember to ask such a question on the wreck.

Reply to
Mike

There is a direction to the flow in AC. It just reverses every 50th or

60th of a second. But at any given instant of time, the current is flowing in a specific direction. During that instant, one wire in, the other out. The next 50th/60th of a second, the in wire becomes the out and the out becomes the in.

Tom Veatch Wichita, KS USA

Reply to
Tom Veatch

The resistance of the wire does not.

Reply to
keithw86

...and it is exactly the supply losses that make the difference, so...

Reply to
keithw86

I understand what your are saying. When on 120v the saw was on a circuit with 4 outlets. The only other item plugged in was a cordless phone charger.

There is a clear difference in start up. I am definitely not an electrical professional, so I can't explain it.

Reply to
DLB

Hide quoted text -

I will probably just wire a separate cord for the 120v lamp. I do like reading all the comments and thank everyone for posting. It all helps me understand more than I did. It makes sense that once running the motor has the same power (one hot leg at 15amps vs. two hot legs at 7.5amps each).

Reply to
DLB

You actually have 240V coming into your house, for the sake of simplicity think of the feed as -120V, 0, +120V. In your panel are two bars which get the -120V, and +120V, the box is tied to the 0V, and ground. This is now the only legal place where they are connected. With a 120V breaker they hit one bar or the other, with a 240V breaker both bars are contacted.

Back to colours, a 240V breaker by convention will have a black and red wire connected to it, -120V and +120V giving a difference of the 240V, if you bring along a neutral (white) wire there is the 120V option, always carry the ground to the end of the circuit, but you can't legally use it to get a 120V circuit.

HTH

Reply to
FrozenNorth

As Dan Coby pointed out, with a 314ft run of 12awg you'd have 6.8% more power available due to reduced supply losses if drawing 10A at 120V. With a typical shop wiring configuration the difference would be less.

There's no way that the reduction in supply losses results in a "wow, start up is almost instant" sort of difference when switching to 240V unless the 120V circuit was way undersized.

Chris

Reply to
Chris Friesen

Absolutely. And I actually did know this before the whole discussion started.

I chose to ignore the line losses because they're supposed to be small to start with on a properly designed circuit, so reducing them further should make very little difference--certainly not one that is noticeable to the user.

The resistance is needed if you want to look at absolute values of line loss rather than ratios.

Surely #10 molded cord sets cost more than #12 or #14?

Chris

Reply to
Chris Friesen

Doug, thanks for your clear reply. I use the same coloring book Leon uses when it comes to electricity so any enlightenment is welcome. I know enough to wire 120 circuits in my sleep, without killing me, or anyone else so far, but

OK, but in my 120 coloring book, electricity comes in the hot wire, and goes out the neutral wire, thus the circuit, or loop is completed. How does this work with 220?

It sounds unsafe to me to be connecting a common ground to the safety ground. In my small world, most of the time the safety ground is a bare copper wire, not even insulated. In a 120 circuit, it would seem anytime the load is hot, the common wire is carrying current back to ground? Also, the motor frame, electrical box etc is connected to the safety ground, would this mean the box/motor frame is hot whenever the the load is on if you used the safety ground as a neutral wire?

In Somona's instance, he has his 240 motor hooked up, plus he has a 120 motor running the feed rollers. Assuming a 3 wire 240 hookup, he could (unsafely, but common in the past?) hook one hot wire to the 120 motor, and use the safety ground as the neutral wire for the 120 motor. If he did this, the safety ground would always be carrying juice when the motor was running, and ergo, anything hooked up to the safety ground, the motor frame, wiring boxes and so on, would also be carrying juice? Is that correct? If so, it sure sounds too dangerous to have been done routinely for 100 years? I'm sure I'm missing something here, but hey, I'm just trying to color in some of the pages:-)

I'm glad you said that. I was thinking damn, I don't even know if my service is 110, 115 or 120? I see all sorts of things on electrical devices. Even this thread is stating 220, or 2 110 lines? You are the only one to correct it so far. No wonder I'm so confused... still alive though:-)

And no, it doesn't need a neutral. 120 needs a neutral;

Again, this confuses me. How is the circuit completed in a 240 circuit?

2 120 lines come from the source to the motor, then what? Where does it go? I bet it has something to do with phase? Each line takes turns being the neutral? If not, I'm lost, if so, still lost:-)
Reply to
Jack Stein

Well, Tom... seeing as we're into semantics now (how unusual for this group) and I quote you:

That is incorrect as a statement. There are those moments when the direction reverses when nothing flows in any direction at all. (Unless you want to open that can of worms called power-factors and phase anomalies where current and voltage are out of step with each other. But we need a lot of very sharp crayons to explain that to the Neanderthals.)

Reply to
Robatoy

Try it and you'll change your tune. Your numbers are only good for steady state current draw. There is a large inrush to start the motor, which will be limited by the supply impedance. At 240V that impedance is the same, though the potential is doubled.

Reply to
krw

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.