Trying to run a two phase well pump

[GLC]

This is what I use to run my well pump and other things.

https://www.amazon.com/gp/product/B092ZD89VN/ref=ppx_yo_dt_b_asin_title_o07_s01?ie=UTF8&th=1

 

[rin67630]

Welcome to the party myself3.

2 phase is like what am electric range runs on, 2 “ hot” legs of 120vac and one neutral leg.

Not necessarily for AC asynchronous motors.The majority of them run on 220V on one phase and generate the second phase from a capacitor.
Look if you have some capacitor value printed on the motor.
Then the only thing you need is a 120-220V transformer and that capacitor. You need also a pure sinus inverter.

 

[Mike 134]

I'm guessing none of you make a living in the electrical industry, correct?

In the USA it is a SINGLE PHASE 230Volt motor. To start it rotating a capacitor is wired into the circuit and then cuts out using a centrifugal switch

 

[Rednecktek]

I'm guessing none of you make a living in the electrical industry, correct?

I'm an electrician on container ships, does that count?

In the USA it is a SINGLE PHASE 230Volt motor. To start it rotating a capacitor is wired into the circuit and then cuts out using a centrifugal switch

With EU/Asia/Everywhere else power it's called a SINGLE PHASE 230Volt motor and requires a start capacitor wired in to get the motor started in the right direction.

How would you differentiate the two if it's exactly the same name for two different motors?

 

[Hedges]

I know enough to be dangerous but not heard of 2 phase power yet.

It does exist, although OP probably isn't working with it.

How to convert 2 phase power supply to 3 phase power supply using a Transformer (like Scott transformer)?

I'm looking to develop a circuit to convert 2 phase power supply to 3 phase power supply. My circuit follows: Input: 2 phase 400V - phase angle 120degree Expected output: 3 phase with phase to...

electronics.stackexchange.com

Two-phase electric power - Wikipedia

en.wikipedia.org

Once you've got two legs out of phase (by anything other than 180 degrees), you can make any and all phases you want with transformers. It's just geometry.

 

[Rednecktek]

It's just geometry.

And dark voodoo magic.

 

[Mike 134]

I'm an electrician on container ships, does that count?


With EU/Asia/Everywhere else power it's called a SINGLE PHASE 230Volt motor and requires a start capacitor wired in to get the motor started in the right direction.

How would you differentiate the two if it's exactly the same name for two different motors?

Yes it does. My question was to those living in the online fantasy world calling it 2 phase. 38 years in the trade NEVER EVER ran across a "2 phase motor"

 

[Hedges]

I'm about to wire a 277/480Y GT PV inverter to 120/208Y battery inverter through transformers.
Once I get 3x 240/480 to 120/240 transformers, I plan to wire it so I also get 120/240V split-phase. Rather than auto-transformer from a single 120V phase, I'm going to add vectors from the other two legs, so they contribute power.



But there's definitely voodoo in transformers.

Try to understand neutral of an auto-transformer carrying current equal to L1 + L2.
"Inrush" is much more complex. When power is disconnected, core ends up as a permanent magnet. Next time power is applied it may magnetize further, saturate, and draw massive current.

To learn more about transformers, try building a "magnetic amplifier" out of them:

Using Roofing Tin as EMP shield

A simple device was designed long ago to always be on standby, ready to make that decision and operate within milliseconds. https://en.wikipedia.org/wiki/Fuse_(electrical) EMP is a microsecond scale voltage level concern; a fuse is a milisecond scale current limiter. If you want to try to...

diysolarforum.com

Also, try wiring a resistor in series with a transformer (to limit current and serve as current sense resistor), use a scope to display waveform, apply DC. Alternate polarity, observe period of time the inductance prevents current flow. Apply voltage same polarity twice in a row and observe time. Use a variac to apply variable AC voltage; somewhere above rated voltage the current will shoot up, no longer a sine wave. You can create S-shaped BH curves from the voltage and current waveforms.

That much is all fun and games.

After employing far more grey matter (or dead chickens) you can take Hc, Br, Bs parameters off the curve and use them for a "Chan" SPICE model (LTSpice is free.) You have to reverse-engineer the math to get core parameters from the winding measurements (involves turn count and core dimensions.) I've done that, not sure I got it correct, but I am able to simulate transformers with these models.

 

[OzSolar]

Below is about the best explanation I've ever found of 240 split phase common to pretty much every house in the United States.

Here's the link.

240VAC Split Phase is produced off a single phase input transformer with center tapped secondary, producing for output, a single phase across the 240V outer terminals and two 120V legs with phases 180 degrees apart. Centertap is an effective ground (Neutral) at 0V potential and each leg is +120VAC and -120VAC respectively for the full voltage of 240V.

If you view the waveform on an oscilloscope, you will see a single sine wave (single phase) when measuring between Line 1 and Line 2 (below) at 240VAC RMS. Measuring between Line 1 and Neutral will show a single sine wave at 120VAC RMS, measuring between Line 2 and Neutral will show a single sine wave at 120VAC RMS equal and opposite to the L1-Neutral wave (180 degree phase shift)

Three Phase has three separate circuits with phases 120 Degrees apart. You need three separate transformers, one for each phase. The primary on each is fed with a single phase and produces an output of a single phase on 208 (Y) or 240 (Delta) VAC. Depending on whether the circuit is Wye or Delta, you can have multiple voltages. Each phase-pair carries the full voltage. On Wye with Neutral, the voltage between the phase and Neutral will be slightly less than three-fifths of (it's one-third of the square root of 3, for electronics geeks) the voltage between each phase leg. On Delta, you only have each phase available with no Neutral.

 

[OzSolar]

This is what I use to run my well pump and other things.

https://www.amazon.com/gp/product/B092ZD89VN/ref=ppx_yo_dt_b_asin_title_o07_s01?ie=UTF8&th=1

Wow that is impressive. Thanks for sending the link. 18,000 watts for 20 seconds sounds an like unbelievable surge rating for a $1,300 inverter/charger. Normally I wouldn't even bother even trying something like that but if it's starting your well pump that says its a pretty serious piece of gear.

Have you captured the starting amps your well pump needs? How long have you been using it?

 

[Hedges]

If you view the waveform on an oscilloscope, you will see a single sine wave (single phase) when measuring between Line 1 and Line 2 (below) at 240VAC RMS.

For extra credit, try actually doing that

(It can be done, but is easier for an EE.)

 

[OzSolar]

For extra credit, try actually doing that

(It can be done, but is easier for an EE.)

It get confusing for me because they seem to exchange "legs" and "phases" randomly. Sometimes they are same thing, sometimes they not. The problem is that it really looks like two phases on a scope? Is that what you're alluding to?

I won't pretend to understand it any more than I have to.

 

[Hedges]

Is that what you're alluding to?

A much more mundane issue, nothing related to signals:

How Not To Destroy an Oscilloscope

In an electronics lab, a recently-built advanced oscilloscope is one of the more costly test instruments. To protect this investment from instant

www.testandmeasurementtips.com

My preferred method is to use a high voltage differential probe as in the first picture. I have one, but since MSRP is as much as a nice scope, most people need another approach.

A decent 10x probe can take 400V peak. Two probes, one on Ch1 for L1, one or Ch2 for L2, display trace for (Ch1 - Ch2)
This is like what you show here, except it doesn't include (Ch1 - Ch2)

View attachment 100446

Another approach I use is an isolation transformer for DUT, so one of its nodes can be ground-referenced to the oscilloscope.

A comment in the article said, "plug your scope into a isolation transformer", but problem with that is chassis of scope is now carrying 120Vrms.

 

[OzSolar]

A comment in the article said, "plug your scope into a isolation transformer", but problem with that is chassis of scope is now carrying 120Vrms.

That reminds me... a few times I've wondered about getting a lower cost oscilloscope to play around with but then I do a bit of research and realize that I have no business trying to use one which has oft been the story my life.