75kva 208 wye load calculation "Balancing"

[Smart $]

I can't eliminate the dunning-kruger effect
what is obvious to the majority will be lost on the minority, but is still obvious

I have no idea what the dunning-kruger effect is and I'm not going to look it up.

Nonetheless, you probably think it is plainly obvious. :blink:

you did not address his query: is the 1.732 factor involved in the load calc
it is

Of course I did not. It was addressed, albeit not plainly obvious, in the first reply by someone other than myself.

you seem to have a rep for nitpicking and redirection
matters not to me
I understand, you are never wrong

Sure, I nit pick, especially when I think it pertinent. Other times simply because it bugs me. You can ignore me if you wish, but I'm not going to change who I am because you don't care for my mannerisms.

And I'll never claim to be never wrong. In fact, I'm often wrong. If it makes you feel better, I'll say I'm wrong now... but it would not be a truthful statement.

 

[Ingenieur]

I have no idea what the dunning-kruger effect is and I'm not going to look it up.

Nonetheless, you probably think it is plainly obvious. :blink:


Of course I did not. It was addressed, albeit not plainly obvious, in the first reply by someone other than myself.


Sure, I nit pick, especially when I think it pertinent. Other times simply because it bugs me. You can ignore me if you wish, but I'm not going to change who I am because you don't care for my mannerisms.

And I'll never claim to be never wrong. In fact, I'm often wrong. If it makes you feel better, I'll say I'm wrong now... but it would not be a truthful statement.

obvious to most

so why post useless information if it does not address his query?

what you think is 'pertinent' is moot to most
so it bugs you and you foist your angst on others?
that's not kosher
I don't care if you change...those around you may feel differently
nothing you can do will 'make me feel better' (or worse)...there is no 'us'
you are wrong: re: dunning-kruger
but the same skill set it takes to arrive at a correct answer is the same as the one it takes to see an incorrect one
go figure

 

[Smart $]

obvious to most

So you believe. Lacks empirical evidence.

so why post useless information if it does not address his query?

My first post in this thread was not useless information IMO.

what you think is 'pertinent' is moot to most

Perhaps. Perhaps not. Who are you to say what I think is pertinent isn't?

so it bugs you and you foist your angst on others?
that's not kosher

Yep. Deal with it.

I don't care if you change...those around you may feel differently
nothing you can do will 'make me feel better' (or worse)...there is no 'us'

Doesn't matter whether you care or not because it's not happening.

Sorry to hear there is no appeasing you.

you are wrong: re: dunning-kruger

How can I be wrong? I made no comment regarding that.

but the same skill set it takes to arrive at a correct answer is the same as the one it takes to see an incorrect one
go figure

Don't have to go figure. Already knew that. So why are you posting useless information?

 

[Ingenieur]

So you believe. Lacks empirical evidence.

My first post in this thread was not useless information IMO.

Perhaps. Perhaps not. Who are you to say what I think is pertinent isn't?

Yep. Deal with it.

Doesn't matter whether you care or not because it's not happening.

Sorry to hear there is no appeasing you.

How can I be wrong? I made no comment regarding that.

Don't have to go figure. Already knew that. So why are you posting useless information?

still fact

in YOUR opinion
in reality, not so much

more likely, perhaps

I don't care...other may, but I doubt it
it's amusing though that you feel compelled to foist your foibles on others without regard for their feelings
so be it

don't be sorry, be constructive

that is your error, no 'pertinent' or relevant comment, pointless information dispersal

if you knew it, why do you continue?
just thought it may help you understand your limitations

 

[don_resqcapt19]

...
they ask a basic question that is never answered
yes, 1.732 is a factor in the load calc

Not really...if you have 48 loads at 1 or 1.1kva that is all you need to know to see if the 75kva transformer is large enough.

 

[Smart $]

still fact

in YOUR opinion
in reality, not so much

more likely, perhaps

I don't care...other may, but I doubt it
it's amusing though that you feel compelled to foist your foibles on others without regard for their feelings
so be it

don't be sorry, be constructive

that is your error, no 'pertinent' or relevant comment, pointless information dispersal

if you knew it, why do you continue?
just thought it may help you understand your limitations

You apparently are unaware of the double standard you show in your comments. I'm going to leave it at that...

 

[topgone]

Where did OP specify this value? I'm thinking it must be a "flavor of the month"...!!!

If you're not well-versed with these types of lighting equipment, please look for a 1000 W, High pressure Sodium, HPF luminaire and see that the lamp plus CWA ballast require 1,100W of power!. Or see it here.

 

[Ingenieur]

You apparently are unaware of the double standard you show in your comments. I'm going to leave it at that...

Irony

 

[Ingenieur]

If you're not well-versed with these types of lighting equipment, please look for a 1000 W, High pressure Sodium, HPF luminaire and see that the lamp plus CWA ballast require 1,100W of power!. Or see it here.

it was an example in response to the op re: 1.732
he was comparing appleranges or 3 ph:1 ph
but you are correct,, modern ballast pf 0.9 so 1000 w/0.9 = 1111 va
but some are as low as 0.5 so a 1000 w fixture requires 2000 va

http://www.hubbelloutdoor.com/content/products/specs/specs_files/balspec.pdf

 

[kwired]

If you're not well-versed with these types of lighting equipment, please look for a 1000 W, High pressure Sodium, HPF luminaire and see that the lamp plus CWA ballast require 1,100W of power!. Or see it here.

OP never mentioned what type of light source he had, just mentioned 1000 watts. If they were incandescent then 1000 watts is it, most of us presume they were an HID luminaire of some sort and that they would have a power factor of less then 1.

 

[topgone]

OP never mentioned what type of light source he had, just mentioned 1000 watts. If they were incandescent then 1000 watts is it, most of us presume they were an HID luminaire of some sort and that they would have a power factor of less then 1.

Agree.
And the answers should revolve around whether or not sqrt(3) will be applied in the calculations! A 208 system would mean a 120V line-to-neutral voltage, meaning that sqrt(3) was applied (208/1.732). The use of a 1,000-W HPS lamp only helps to arrive at a representative line current figure! That should clear things up here.

 

[Besoeker]

OK,
Got a 75kva 208 wye transformer. so 75kva will give me 208Amps, need to ligt up 48 1'000watt lamps single phase.
48 lamps @ 1'000watts is 230amps:blink: But! Its a 3phase system . So does the 1.732 rule apply?

Yes, you would have had to use the 1.732 (sqrt(3)) to get the 208A in the first instance unless that was a given.
And that 208A is the maximum current you can take from each line. It's no more complicated than that.

 

[kwired]

Yes, you would have had to use the 1.732 (sqrt(3)) to get the 208A in the first instance unless that was a given.
And that 208A is the maximum current you can take from each line. It's no more complicated than that.

10 amps connected A to B and 10 amps connected B to C however does not give you 20 amps net on B, next common conclusion might be it has 10 amps on B and that is also incorrect.

 

[Besoeker]

10 amps connected A to B and 10 amps connected B to C however does not give you 20 amps net on B, next common conclusion might be it has 10 amps on B and that is also incorrect.

But his loads are not A to B etc. They are single phase so the currents would be A to N etc. and the max he can pull from any phase is 208A.

 

[Ingenieur]

pretty much 208 no matter how you slice it

single phase 25000/120 = 208
three 75000/(208 sqrt3) = 208
using 2 phases/legs = 208 (90 deg) = 25000/(208 0 deg) - 25000/(208 120 deg)

 

[Tony S]

pretty much 208 no matter how you slice it

single phase 25000/120 = 208
three 75000/(208 sqrt3) = 208
using 2 phases/legs = 208 (90 deg) = 25000/(208 0 deg) - 25000/(208 120 deg)

Where did the 90deg come from :?

 

[Ingenieur]

Where did the 90deg come from :?

....

 

[Smart $]

But his loads are not A to B etc. They are single phase so the currents would be A to N etc. and the max he can pull from any phase is 208A.

Neither load connection nor voltage was specified by the OP'er. Fixtures could be 208V connected, i.e. A-B, B-C, C-A, and balanced typically. Or they could be 120V connected, i.e. A-N, B-N, C-N, and balanced typically. In either case, 208A is the rated current for each of A, B, and C lines.

 

[kwired]

But his loads are not A to B etc. They are single phase so the currents would be A to N etc. and the max he can pull from any phase is 208A.

Neither load connection nor voltage was specified by the OP'er. Fixtures could be 208V connected, i.e. A-B, B-C, C-A, and balanced typically. Or they could be 120V connected, i.e. A-N, B-N, C-N, and balanced typically. In either case, 208A is the rated current for each of A, B, and C lines.

I agree OP did not outright say what voltage the luminaires operate at, but from what was mentioned in OP particularly his apparent single phase amp calculation it seems they likely are connected to 208 volts.

 

[Besoeker]

I agree OP did not outright say what voltage the luminaires operate at, but from what was mentioned in OP particularly his apparent single phase amp calculation it seems they likely are connected to 208 volts.

It doesn't matter. My point remains that he can't take more than 208A from any line.