Fast Delta Calc

[Toros]

Hi ,
Do you think that I can estimate a remodeled warehouse load supplied by the existing 120/240V, 4wire, 3 phase service
this way ?????????;:?

General ltg w/ 25% LCL = 2400VA @ 120/240v, 1 ph. = 10A
Gen. use recept @ 100= 2400VA= @ 120/240, 1ph= 10A
special . use recept @ 100= 4800VA= @ 120/240, 1ph= 20A
miscel. @ 100= 1200VA= @ 120/240, 1ph= 5A

Motorized load @ 100= 12,450VA @ 415V, 1ph= 30A (some used the high leg)
roof mtd AC load @ 100= 12,450VA @ 415V, 3ph= 30A

sub total , 2pole+3 ph loads= 60A
sub total, 1 ph, grounded loads= 45A
Largest motor @ 25%= 2075VA @ 415V= 5 A
120% PF for existing-old motorized loads= (13000 x 1.2= 15,600 / 415V= 38A

Concluded that;
minimum service @ 120/240, 3 ph, 4w required is; 148A

Thank you

 

[david luchini]

Hi ,

roof mtd AC load @ 100= 12,450VA @ 415V, 3ph= 30A

...

Concluded that;
minimum service @ 120/240, 3 ph, 4w required is; 148A

Where is the 415V coming from?

 

[Besoeker]

Where is the 415V coming from?

One might also wonder abput this:

"the existing 120/240V, 4wire, 3 phase? service "

 

[Toros]

Where is the 415V coming from?

240v x 1.73=415 v

 

[Besoeker]

240v x 1.73=415 v

Sounds like EU voltages. Except for the 120V.

 

[mbrooke]

Sounds like EU voltages. Except for the 120V.

Its this:

Delta high leg is great for long runs because standard 208-230 volt motors are unlikely to encounter under voltage issues.

 

[MyCleveland]

mbrooke

Excellent graphics....can I ask what program was used to generate, or was this all cut and paste ?

 

[Besoeker]

Its this:

Delta high leg is great for long runs because standard 208-230 volt motors are unlikely to encounter under voltage issues.

But no mention of 415V.

 

[mbrooke]

mbrooke

Excellent graphics....can I ask what program was used to generate, or was this all cut and paste ?

They are Mike Holt's. Not sure what program he or his team made them on, but they sure are the best graphics bar none.

But no mention of 415V.

Oppps- missed that :ashamed1: But to be fair you do get 415 volts L-N on a 240/480 delta.

 

[Besoeker]

They are Mike Holt's. Not sure what program he or his team made them on, but they sure are the best graphics bar none.




Oppps- missed that :ashamed1: But to be fair you do get 415 volts L-N on a 240/480 delta.

Don't see how but then I'm thick according to one of the mods here.

 

[jumper]

Don't see how but then I'm thick according to one of the mods here.

The OP was taking a math shortcut, like using 360 for calculating VA for a 3 phase load on a 208Y/120 source.

 

[Besoeker]

The OP was taking a math shortcut, like using 360 for calculating VA for a 3 phase load on a 208Y/120 source.

And the 415V?
Still as thick as two short planks.

 

[jumper]

And the 415V?
Still as thick as two short planks.

Post #4

240v x 1.73=415 v

 

[mbrooke]

Don't see how but then I'm thick according to one of the mods here.

208x2=416

 

[jumper]

208x2=416

What the heck is this? Nothing to do with 240D/120V 3 phase calculation.

 

[mbrooke]

What the heck is this? Nothing to do with 240D/120V 3 phase calculation.

Never mind- I was replying to Besoker. A 480 volt high leg is 416- double that of 208. But since the 415 in question is 3 phase, I was wrong.

 

[Julius Right]

:happyyes:

 

[jumper]

View attachment 19302 :happyyes:

Yes, but the OP does not have a wye secondary.

A 240V wye would be uncommon for most typical applications because unshown in that graphic is the center point ground connection and one would get 139V for L-N(G), Not very useful for receptacles and such.

And please please no one bring up an ungrounded wye, my little brain cannot handle it.