Quote from: SupaDude on March 30, 2018, 05:46:17 PM

1) How many S9 miners can we run with 150KVA transformer, 400A 3Phase, 208v? Please post your calculation formulae, I want to see how far my math and education is off.
2) We have (30) 2pole 20A breakers planned to feed 5 shelves with 60 S'9s and 10 L3"s
3) What is the best UL certified PDU option for rows of 10 miners?
4) Who has the best pricing on industrial shelving and what vendors?

With a 150 KVA transformer you can technically squeeze 416 amps out of it on each line. That is called your full load amps. But as you get closer to 100% capacity the thing is going to get super hot and you start to lose a bit of efficiency, depending on the transformer.

Now, if you are in USA you will wire your receptacles line-to-line, 2 hot wires of 120v. So the formula is:

Amps = Watts / (Sqrt(3) * Power factor * Volts)

So if your first plug uses line A and line B then each line will be loaded with 7.44 amps. You get this by 1455w/(110v * 94%) for each line. If you add a second machine on to line A and line C, then line A now has 12.9 amps and lines B and C have 7.4 amps. Your load total is the number of amps that is the largest of the three.

Math answer DO NOT DO THIS: If you perfectly balanced your phases and loaded your transformer to 100% you could technically have about 96 machines but your transformer is going to be super hot and angry. I definitely would not recommend to EVER load to 100%.

For me, 58-60 machines would be a sweet spot for a 150 KVA transformer. 50%-60% load is efficient and a safe area to be in. Rule of thumb, 80% should be your max.

So each 2 pole breaker is 2 machines.

As for PDU's I can't recommend anything since it really depends what you want the PDU to do. You will have a lot of empty plugs since PDU's usually don't have 1400w+ machines loaded onto it in a data center. You can run directly to outlets if you want cost-effective. Make sure to use the correct rated outlet for your voltage.

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