Electrical question

[Bluedog225]

Thanks Matt. That makes sense.

 

[timselectric]

The other half is 180 degrees apart

Not 180deg apart. It's single phase.

 

[Mattb4]

Not 180deg apart. It's single phase.

In relation to the other half transformer output it is 180 degrees apart. Do not be dense.

 

[timselectric]

In relation to the other half transformer output it is 180 degrees apart. Do not be dense.

Incorrect
You are just adding to the confusion.
Current flows through both halves in the same direction.

 

[Mattb4]

Incorrect
You are just adding to the confusion.

Oh well, once again I am forced to put you back on ignore.

 

[Bluedog225]

I found the PN breaker. That’s pretty slick.

If I run this off one Quattro, I understand the need to put a jumper between the top 2 main lugs.

What does that look like? I’ll have the line coming in from the inverter. Do I stack the jumper (a piece of wire) with the inverter line? Or is the jumper a store-bought thing like a little bus bar? Google no help.

Thanks

 

[timselectric]

I found the PN breaker. That’s pretty slick.

If I run this off one Quattro, I understand the need to put a jumper between the top 2 main lugs.

What does that look like? I’ll have the line coming in from the inverter. Do I stack the jumper (a piece of wire) with the inverter line? Or is the jumper a store-bought thing like a little bus bar? Google no help.

Thanks

A piece of wire is fine.

 

[Mattb4]

Just in case it helps here is a nice video about the subject.

Note the 2 waves 180 degrees apart. (7:20 into the video)

 

[timselectric]

Just in case it helps here is a nice video about the subject.

Note the 2 waves 180 degrees apart. (7:20 into the video)

It's one sinewave. But if you hook the scope leads up with the primary on the neutral. It allows you to look at the two halves separately. But they're not 180deg apart from each other. It's one wave, displayed in two halves.
The guy in that video is also confused.

 

[Bluedog225]

To test my understanding. 3 phase as uses on high voltage transmission from a generating station is actually 3 sinewaves out of phase by 120.

While split phase is one sinewave tapped in middle of a transformer to split it into two parts. L1 and L2. Each 120 volts from neutral. And 240 volts from each other (peak to peak).

I’ve been wondering about this for years. Thanks

 

[timselectric]

To test my understanding. 3 phase as uses on high voltage transmission from a generating station is actually 3 sinewaves out of phase by 120.

While split phase is one sinewave tapped in middle of a transformer to split it into two parts. L1 and L2. Each 120 volts from neutral. And 240 volts from each other (peak to peak).

I’ve been wondering about this for years. Thanks

Yup, you've got it.

 

[Bluedog225]

Does it make sense to use this load center as my main panel in the power shack?

Or is it smarter/better to have a smaller main panel (2 or 3 breakers) in the power shack and use this box as the subpanel in the cabin?

Seems like this box is better as a sub-panel in the cabin.

 

[Supervstech]

It's one sinewave. But if you hook the scope leads up with the primary on the neutral. It allows you to look at the two halves separately. But they're not 180deg apart from each other. It's one wave, displayed in two halves.
The guy in that video is also confused.

You are correct...

HOWEVER... when configuring a stackable inverter that is configurable for split phase or 3 phase...
You have to select 180⁰ separation to get split phase 240V.
As from the perspective of the neutral conductor, it is 180Degrees between L1 and L2. True, those degrees are all in the same direction of the wave, but they are peak to peak 180⁰ of separation between the neutral.

I do not know why you argue this so much.

It is certainly not TWO different phases!
But the lines are seperated out 180 degrees at the peaks. Just like any wave would be from the midpoint.

 

[timselectric]

You have to select 180⁰ separation to get split phase 240V.

You select 180deg on the inverters. So that they know that they are wired in reverse of each other. It has nothing to do with the sinewave.

But the lines are seperated out 180 degrees at the peaks. Just like any wave would be from the midpoint.

They aren't.
You are splitting the voltage. But the sinewave remains the same.
Midpoint is zero crossing. Between the alternations of current flow.

 

[Bluedog225]

Put another way, how do I get a single, large conductor out of the main panel in the power shack to the cabin?

Do I need to put in the largest breaker I can find and run the single conducter off of it? E.g. 100 amps.

Seems like a single 100 amp breaker would handle two quattros. 5000 max watts/120 volts=82 amps

 

[timselectric]

I wouldn't want 82a of 120v. You will be better off going split-phase with two Quatros in my opinion.
(Assuming that they can be configured for split-phase)
Smaller breaker and wires, for the same amount of power. But, you will have to balance your loads.

 

[740GLE]

When measuring any voltage be it AC or DC the negative lead is your reference lead. Measuring 120 vs 240 you are changing that reference lead location.

It might make better sense to some to see how the coils of a standard transformer is wired to proved 120/240. This way it’s very clear how you’re measuring across two completely different references.

 

[Bluedog225]

I’ve been reading up on balancing loads for split phase.

Is there an efficiency penalty for a load that is not balanced? Or is it just a matter of not overloading the capacity for each leg?

I ask because given my loads, I’ll be unbalanced most of the time. Mostly air con versus other house loads. Does it matter?

I wanted to pin this down so I can evaluate the inverter cost, wire cost, and split phase wire savings.

Thanks

 

[Hedges]

If inverter has separate 120V inverters for each leg, then efficiency is reduced with higher power on one leg.
Inverter loss is a no-load wattage, and an I^2R term, current squared times resistance (of FETs and inductors.)

My System Efficiency is 81.3%. Prove me wrong or show me your math.

System efficiency is low on my list of priorities, assuming they all are going to be fairly close.. The value to me is to be able to take advantage of solar and TOU rates in California.

diysolarforum.com

Few percent, though.
More important the system is robust, doesn't shut down due to overload.
Note also inverter wattage is derated with heat, so in hot weather you could overload earlier than expected.

Most of this isn't published by most manufacturers.
SMA did (my link above). I also was surprised by how much faster their 4500W model derated with heat compared to 6000W model (seen in manual.)

 

[timselectric]

You will never be perfectly balanced. You just don't want to be heavily unbalanced.