Each winding makes 120 volts. 1t is a 12 lead machine which means that there are 6 windings.

The way I see it is 45,000 watts divided by 120 volts times .8 power factor = 300 amps (output of all windings at once)

Divide this by 6 windings = 50 amps per winding.

I have no clue why the name plate says 245 amps. Nor does it seem to specify at what voltage the 245 amps is at.

It's also curious why it says it's 1 phase while it's a 12 lead generator, and the voltage listed is 120/208. If anybody has any insight on this I would love to hear from you.

I have this machine wired in a double delta configuration for single phase; 120/240 volts (see schematic above)

That gives me (two) 3 phase 120 volt deltas connected together at a corner which makes the neutral. The way I see it; each delta can safely produce 100 amps@ 120 volts.

So I think I can safely pull 100 amps@ 240 volts or a total of 200 amps@ 120 volts (single phase).

To put it plainly, If the two single phase "hots" from the generator go through a 100 amp 240 volt breaker before the transfer switch, I should be good.

Does this sound reasonable to anybody here?

Thanks.

180' total... (80' from main panel to house wall exit.. underground feed 100' to pole bdg)

planning on aluminim conductors... Thinking continuous run of 2/0-2/0-2/0-1.

Though if 3 ea. 1/0 will carry the load that distance.. prefer that less expensive route.. ]]>

So where does that EPO need to be.

Also the last paragraph in (B) (which I think ought to have been (C) requires yet another EPO, and this time it gives a choice of two locations. So it seems to me, to meet the requirements of 445.18 (disregarding the disconnect requirements of 700 through 702), you could put in two EPO's; one lockable open and one not necessarily outside the enclosure of the generator right next to each other.

Is it me, or is this not nailed down as well as it could be? ]]>

From what I have gleaned from extensive google-fu, i have found the following to be a possible code compliant transformer installation, my questions will be posed after:

75KVA 480D - 120/208Y

Primary OCPD:

75000 / (480x1.732) = 90.21A ----------> 90.21A x 1.25 = 112.76A --------> Next size up = 125A OCPD

Secondary OCPD (Transformer will feed panelboard with branch circuits):

75000 / (208x1.732) = 208.19A -----------> (assuming continuous load is 100% of transformer rating) 208.19 x 1.25 = 260.23A ---------> Next size up = 300A OCPD

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If what i've suggested above is correct, and one can provide a 300 amp panelboard from a 75KVA transformer, is it then kosher to load this panel up to 80%, which would be 240A/phase and approximately 15% overload of the 75KVA transformer rating? I want to say no, because the load was only calculated for a 75KVA transformer, but i could see people in the field seeing a 300 amp panel with room to spare and not considering the load on the transformer.

I guess i'm also having trouble understanding the usable KVA that can be loaded on a transformer vs. acceptable OCPD. ]]>

I have been requested to provide a fault current for a new 400 Amp 3-position ganged meter base. The service will be fed from a 150kVA Open-Delta bank on a 7200/12470 Volt system consisting of a 100kVA lighter pot and a 50kVA power pot both with an impedance of 1.5% . The service will be fed with 1/0 triplex w a #2 reduced neutral approximately 75 feet long. The different fault calculators i have give me approx. 42,000 Amps at the secondary bushings of the transformer but I know it will be less at the meter base. Any help figuring this out is greatly appreciated. Thank you. ]]>

I have been requested to provide a fault calculation for a new 400 Amp single phase service. The service will feed from an Open Delta Bank consisting of a 100kVA lighter pot and a 50kVA power pot both with an impedance of 1.5%. The different calculators that I have available give a fault current of approx. 42,000 Amps at the secondary bushings. But since the service length will be around 75 feet of 1/0 overhead triplex with a #2 reduced neutral, I know that the fault current will be less at the meter base. I don't want to give the fault current at the transformer because it will force the contractor to install higher rated gear and cost more money. Any help would be appreciated on how to figure out the fault current at the meter base. Thank you. ]]>

The question is something like this... System is WYE-Grounded. The voltages are 480V. Fuse B blows. What are the voltages now?

a) A-0 B-480 C-0

b) A-0 B-277 C-0

c) A-277 B-0 C-277

d) A-480 B-0 C-480

is it common that the utility can distribute 240/120V, single phase (for residential loads) from Delta 3-Ph, 4-Wire transformer? I have a situation where the utility wants to provide a 240V/120V single phase service to 5-trailers each will require (150A, 240/120V, 1-ph). Since the only way to get 120/240V service is from the A-C & neutral (center tap). I have additional questions:

1. Does the main service distribution panel needs to be 240V, 3-Ph, 4-wire, and we only use the C-A phase & neutral to serve all these loads? Or the main distribution panel service needs to be single phase since it will only utilize C-A phase & neutral?

2. My understanding for the 240/120V, 3Ph, 4-W system we can't have 120V loads more than 5% of the transformer rated KVA and I'm sure this will exceed that but the utility co saying they have no concerns of that. Is this accurate statement?

Thanks in advance! ]]>

I have seen several aftermarket MCC buckets of one manufacturer be placed in an MCC structure for another manufacturer. For example I've seen Cuttler Hammer MCC buckets replace existing buckets in a Square D MCC.

Does each manufacturer list their MCC for some of their competitors buckets knowing they will likely also place their buckets in the competitions MCC's or are the buckets listed individually and completely separate from the structure rating? ]]>

Would I only be able to test between individual line conductors? For example, instead of applying 1500 VAC between L1 and Ground, I would just apply 1500VAC between L1 and L2, and check for any current coming back on L2? ]]>

Would you still leave X5 as the grounded tap? Or would you move your grounding to the new center point (X4)?