Miller Dynasty 280DX - Hard Choices!

[Robert Hall]

Three phase, at least here, is charged differently. Three phase could cost you more as part of the way the rates are setup, inductance is part of the charge schedule.

[shovelon]

Yes I am familiar with this relationship. So why does Terry say the power bill is lower on 3 phase with an inverter machine? The Power bill measures Joules, right? The meter doesn't care about voltage.

I am not an electrical engineer, my father was.

But I reckon the surge at the meter on a 3 phase meter is much less than that on a single phase meter.

I am just going on what my father advised me and observation. Beyond that I can't comment.

[shovelon]

Three phase, at least here, is charged differently. Three phase could cost you more as part of the way the rates are setup, inductance is part of the charge schedule.

Like induction motors?

[Willie B]

Any electric meter I'm aware of measures voltage and current to read wattage, if your usage isn't efficient you need to turn it up to do the same job. The power meter reads more. As Nicola Tesla preached, three phase is a more efficient way to use power. At 577 volts 1 amp supplies a 1 HP motor. We can usually supply these motors with #14 wire! Usually little energy is wasted in line loss. Motors on three phase start easier, produce more torque, and don't need starters. They cost less to build. I guess welders are a similar story. I know older technology 3 phase welders weld smoother.
The down side of three phase is it costs more. Installation costs are higher. A kilowatt of electricity costs more. Green Mountain Power "demand meters" three phase. The cost per kwh is based on a multiplier of your peak load. Use 1000 amps for 15 minutes a month, pay extra for the whole month.
We once 30 years ago wired a sawmill. This was a shoestring project. They used a bunch of second hand equipment. We started it for a half hour, discovered a bad machine, and waited a month for parts. The electric bill was $1200.00! 3 phase may be efficient, it isn't always cost efficient.

[Robert Hall]

Like induction motors?

Correct.

[atg]

Sounds like one of those phase perfect converters might pay for itself pretty quickly.

[Silicon-based]

No, it wouldn't. As mentioned above, that would be like a perpetual-motion machine, meaning it won't work. Modern inverters like the Dyn280 utilize single-phase current as efficiently as they do three-phase current. Adding another gizmo between the power line and the welder will only add more inefficiencies to the process.

Just plug the d@mn thing in and weld!

John

[atg]

No, it wouldn't. As mentioned above, that would be like a perpetual-motion machine, meaning it won't work. Modern inverters like the Dyn280 utilize single-phase current as efficiently as they do three-phase current. Adding another gizmo between the power line and the welder will only add more inefficiencies to the process.

Just plug the d@mn thing in and weld!

John

Yah I didn't mean pay for itself for use with an inverter welder. I meant rather than paying to have three phase power hooked up to your house for whatever reason, given the differences in the way it is billed, if you had 3phase equipment to run.

but this is a 280 thread so I am off topic.

[con_fuse9]

The efficiency advantage of an inverter is simply how much heat the welder itself produces.
Things that get hot are less efficient that things that stay room temp.

As for 1phase vs. 3phase. With 3 phase, the power is essentially moving along 3 wires/circuits, with 2 phase its 2 wires. With 3 wires there is a neutral but on higher power stuff its typically phase to phase (so you are not draining 3 phases worth of current through a single neutral...). Anyway, with 3 phase you are spreading the power along 3 circuits, not 2. That means you are spreading the heat. So you have potentially more power and/or higher duty cycle.

As far as measuring Watts by actually measuring volts and amps. While that was the old way of doing it, the new meters are supposed to measure power either more directly or at least compensate for phase. You hear about "power factor" and that is essentially when current (amps) lags behind voltage. An analogy would be you turning on a garden hose - takes some time before the hose fills and water squirts out the end. Since the input is a sine wave (at 60 sine waves per second) this constant lag means that the peak voltage happens at a different time than peak current. So to properly measure power you should take instantaneous readings of voltage and current and multiply. If you just take peak, the wattage reading will be too high.

If your electric bill is high enough, I would have this conversation with the power company about what meter you have and what kind of load you are presenting.

BTW, capacitors tend to not like voltage changes (so voltage lags current) and inductors/transformers don't like current (amps) changes (so current lags voltage).

[zank]

y'all are a bunch of enablers. got my tracking number this morning.

[Robert Hall]

Bwahahahahaa

[Robert Hall]

I've been using the 350dx lately for stick practice but have not yet done any aluminum. I will be in the next week or so and want to mess with the en/ep amplitude to see what trouble I can cause myself.

[zank]

Loving the new machine!


Todd P by Zanconato Custom Cycles, on Flickr


Todd P by Zanconato Custom Cycles, on Flickr


Rebecca Z by Zanconato Custom Cycles, on Flickr


Rebecca Z by Zanconato Custom Cycles, on Flickr


Rebecca Z by Zanconato Custom Cycles, on Flickr

[AKweldshop]

Oh man those are pretty!!

[Robert Hall]

Nice!

[Heartdoc]

Hey, I just bought that machine and my welds look NOTHING like that! I think my machine is defective. No, wait....I must be defective! Oh well, lots more practice to be had. Great looking welds, Zank!

[shovelon]

Holy-Moly Mike!

Those a pretty dang nice!

[zank]

The machine makes it feel like cheating, Terry.

Thanks, fellas. Lots to experiment with now.