Visit our Popular Forums

sailingharry · 09-09-2023, 19:10

Quote:

Originally Posted by Chotu

In DC, the traffic can be absolutely horrendous and it’s not a fantastic destination by boat either. It’s quite out of the way. VA is known to have terrible traffic as well but only on the VA/DC border. A lot of people think VA=DC , but VA is fairly rural, as is W VA.
However, considering all the traffic and convenience by boat as factors,, Watts the formula for the best place to visit? … pffffff! Might as well just go to AC and enjoy yourself! Easier to get to by boat too!

No one should be confused. This is all perfectly gin clear. Like the water in the Chesapeake

[emoji106][emoji106] now we have a sensible answer to this asinine discussion!

Jamme · 10-09-2023, 17:23

Quote:

Originally Posted by JBP

The big question is, are you going to share those pretzels?

Anytime mate! Pretzels are Very Important: P=VI

[emoji8]

jeanathon · 10-09-2023, 19:04

Quote:

Originally Posted by JBP

If the pretzels at the bottom of the bag have lost their salt, let's call it their "Pretzel Factor", you can still have a satisfying result if you alternate your pretzel selection between the bottom and top, or "Alternating Consumption". If all the pretzels have the same amount of Pretzel Factor then you can eat them straight off the top or "Direct Consumption ". This proves AC must address PF, but DC does not.

The big question is, are you going to share those pretzels?

Don't bogart those pretzels!

Baronkrak · 21-09-2023, 07:54

Quote:

Originally Posted by Fuss

We have this endless point that some of us don't know the difference between Amps and Amp Hours. It consumes many pages of many threads.

According to StuM.

Quote:

Originally Posted by StuM

Either confused or just unaware of the correct terminology.

Baronkrak · 07-10-2023, 03:23

[QUOTE=wyb2;

"In terms of [URL="https://en.wikipedia.org/wiki/Electromagnetism"]electromagnetism[/URL], [URL="https://en.wikipedia.org/wiki/Electrical_work"]...........

So wiki is where you get your formal education from.

According to StuM.

Quote:

Originally Posted by StuM

(FWIW, I wouldn't put too much faith in advice from sources which can't even get the basic units right)

And Wiki is one of these sources.

Quote:

Originally Posted by wyb2

Volt-amperes are usually used for analyzing alternating current

You omitted to print the following from Wiki:
(VA rating is most used for generators and transformers, and other power handling equipment, where loads may be reactive (inductive or capacitive))

Manufacturers of alternators, inverters, transformers rate their product in VA simply because they do not know at what power factor their equipment will be used.

This is why VA should be used, as the unit of power, when the power factor is unknown or nonexistent.

Shanachie · 07-10-2023, 07:40

Just curious: Is this what you folks talk about at social gatherings? Whoa! Get me another drink!

wyb2 · 11-10-2023, 07:42

Oh fun, we are restarting the merry-go-round.

Quote:

Originally Posted by Baronkrak

Manufacturers of alternators, inverters, transformers rate their product in VA simply because they do not know at what power factor their AC equipment will be used.

This is why VA should be used, as the unit of power, when the power factor is unknown ~~or nonexistent~~.

Fixed.

Hey, find literally any source that supports your claim that W is an “incorrect” unit for DC systems, and I’m happy to read it. But until then, it sure seems like you just made something up for the sake of getting people to argue with you over it.

Baronkrak · 12-10-2023, 06:30

Quote:

Originally Posted by wyb2

Oh fun, we are restarting the merry-go-round.

Fixed.

Hey, find literally any source that supports your claim that W is an “incorrect” unit for DC systems, and I’m happy to read it. But until then, it sure seems like you just made something up for the sake of getting people to argue with you over it.

That one is unable to make the difference between W and VA is understandable, it is just an example of Truth Decay.

sailingharry · 13-10-2023, 04:15

Quote:

Originally Posted by Baronkrak

That one is unable to make the difference between W and VA is understandable, it is just an example of Truth Decay.

I do understand the difference. I understand power factor. I understand phase angle. I understand the huge impact that power factor (usually inductive) has on power delivery (wire and transformer sizes, mostly) and inverter design (again, current handling components). I am a degreed and licensed engineer, and the last decade of my career included huge (MW) inverters supporting Navy data centers where pf was a big issue.

Some concepts:
VA can produce no power. A 1000 VA load at a pf of 0 consumes no power from your battery (except losses). It is why you buy power from the utility in kWh, not kVAh.
W is purely power. W fill (or empty) a battery. They turn a motor. They light a bulb. No load on your boat (or house) is rated in VA. Even your inverter, as a load, is rated in W -- but as a SOURCE is rated in VA.
VA is a power delivery concept, not a device concept. No motor is rated in VA -- they are rated in HP (which convert directly to kW). Computer power supplies are rated in W, but have a significant pf and so consume more VA.
pf is, as a practical matter, impossible to discuss for a DC circuit. If W=pf*VA, what typical pf do you use for DC, how do you calculate it, and what do you use VA for?
As wyb2 points out, VA is irrelevant to DC. But, as he points out, we would love you to show us a single scholarly article supporting your position. If your position is right, you should find many supporting sources. We certainly didn't have any in college.

Baronkrak · 13-10-2023, 05:58

Quote:

Originally Posted by sailingharry

I am a degreed and licensed engineer,

Then you must have learned what cause a current to lag voltage?

sailingharry · 13-10-2023, 07:51

Quote:

Originally Posted by Baronkrak

Then you must have learned what cause a current to lag voltage?

Indeed. I know what causes it to lag, and what causes it to lead. But how is that relevant to using W for power in either AC or DC, and how does it make VA at all relevant in a DC system?

W is the appropriate unit for power -- in AC or DC.
VA is an appropriate unit for power delivery systems in AC. But what relevance at all does VA have in DC systems? None, which is why it is not ever used.

wyb2 · 13-10-2023, 09:11

Quote:

Originally Posted by Baronkrak

Then you must have learned what cause a current to lag voltage?

It’s like trolls all have to take the same class before going online.

[instructor] Remember class, what do we do when someone posts a clear and complete argument?

[class, in unison] “quote a single sentence and redirect”

[instructor] That’s right. Never engage with larger point.

Baronkrak · 13-10-2023, 10:24

Quote:

Originally Posted by sailingharry

Some concepts:
VA can produce no power.

So when 10A flow out of a 12V battery this is not power?

team karst · 13-10-2023, 10:39

Quote:

Originally Posted by Baronkrak

So when 10A flow out of a 12V battery this is not power?

It is exactly 120 Watts of power.
That is the DC story.

U can have 10A at 12 V of AC , and have zero power transfer, however. It could be anything from zero Watts to 120 Watts for the ac case.
The math explains it more precisely. Its the vector multiplication of two time variant sinewave quantities. So, there is a case where over time, that value is zero.