Topic: Single Phase verse 3 Phase (Read 1326 times)

For reference a s9 pulls around 1,230-1,300w using the Bitmain APW1600 PSU (Platinum). On 208v that = .5.4A or if using a PSU that can use it (the APW1600 is 208-240v only), for 120v feed 10.8A.

Another thing to consider that there are few 1,500-1,600w PSU's that can run off of 120v and they are pricey. OTH server PSU's which all use 208-240v can be easily and fairly cheaply had up to 4KW of 12vdc power out + they are pretty bullet-proof.

Hi, not sure how many amps those S9 pull so you still have to worry about overloading the circuit. I ended up running all new circuits to my data room because older house and too many unknowns to be running 24/7 on old wiring

 but balancing shouldn't be an issue on 1 rig

240v electric is  a little more efficient so you'll save a little on electric, not much.  but it's cheaper to install because you don't run a neutral, so less wire.

2 120v circuits will use twice as much wire as 1 240v circuit, which means less wires in the conduit & less heat buildup, so less conduit too

Hi Sidehack,
Thx for taking the time to answer the question. Wish I had done this research the first go around In general, do folks who go 240v save a substantial amount of money for electricity compared to those running 120v?

TxSteve,
Got it. I've been running just 1 S9 off one circuit so if I'm understanding correctly balancing is not an issue in those cases?

NotFuzzyWarm,
Thanks

My hosting is all run on 3-phase because that's what was provided to the shop I'm in. I have three shelves, each one supplied with 208V by drawing from two of the three legs. First thing I did was install current meters on each leg at the junction box dropping to each shelf's sub-panel so I could monitor the power on each leg and keep things balanced. With a balanced three-phase, just like with a balanced split single phase, there will be no current on the neutral leg and that makes the most efficient use of the power line and transformers.

Running on 240V instead of 120V keeps things balanced automatically, because you have two hot legs and if they're both sourcing the total load then each leg is supplying the same power into the load.

For a given load, using higher voltage means lower current required. Copper loss (resistive loss in the mains wiring) is proportional to current squared, so if you double the voltage you halve the current and quarter the copper loss. Total system efficiency is increased. A good active-PFC PSU (the only thing you should be using given the loads you'll be drawing) will take the input AC and boost it to a DC bus around 380V. If the input voltage is already high (and the current low), that booster won't have to work as hard and your PSU will be more efficient.

if you are just running 1 miner it's probably no problem if nothing else on circuit, but when you have multiple PSU's on 120v circuit they get randomly plugged into either the A or B 120v leg -- if you are running multiple heavy loads 24/7 you want to make sure the amp draw is about the same on both legs. You can use an ammeter in the panel to check it, and make adjustments

when I was on 120v, after a close call(blew the meter up) with unbalanced legs, I mapped out each circuit. I was running titans which require 2 psu, so I plugged 1 psu into each leg. So no matter how I turned the rigs on and off I was still balanced.

with 240v you don't have to worry about balancing because it draws 120v equally from each leg

And I wouldn't want to use a 15a circuit, use 20a #12 wire drawing no more than 16a continuous

you really should talk to an electrician, because running this stuff 24/7 you don't want to even be  close to  maxed out. And put an ammeter on any circuit in the panel than is running a miner to make sure you aren't drawing too many amps on that circuit

oh you also want to make sure you are using heavy duty 20a recepatacles and not the standard light duty residential receptacles. I have a laser temp gun  and walk around reading temps of receptacles, plugs, psus, etc -- anything that is hot is a problem, especially a light duty receptacle in a wall that's hot !!

Keeping loads balanced applies the same with split 3-phase loads as with split 240v single-phase  (L1 120v - Neutral - L2 120v). Simply put it's more of an issue with the service transformers than the users but will result in one side of the line(s) being higher voltage than the others leading to unbalanced currents in the transformers.

Txsteve,
thx for the reply. I'm new to the electricity lingo world but know the basics. I have a few follow up questions if you don't mind. What actually makes the 240V versus 120V better and how does one "balance" the circuits? For example, if someone was using 120v and just ran their S9 miner at home off a standard 15amp circuit, how does the balancing come into play? Thanks again

use single phase but run 240v circuits for your mining then you don't have to do any balancing, 240v draws equally from both legs -- most psu run off 240v too, just need a different plug on psu -- I made the switch from 120v to 240 awhile ago, and 240v is so much better

to make things even easier get 240v 50amp PDUs from Finksy here on bitcointalk, then you can run 50 amp circuit and plug the PSUs into the PDU -- real easy

NotFuzzyWarm,
Much thanks for the detailed explanation. It was really helpful. If it's a single phase that gets split into 120V circuits, what are the consequences from a mining standpoint of the "balancing act" you mentioned?

1 vs 3 phase only really matters for industrial or large commercial loads such as large motors, induction heaters, electric furnaces/ovens and such. Things that are designed to directly use the 3-phase line..

For mining, since all the PSU's are single phase then it makes perfect sense to use single phase, especially if there is price difference between the 2. Remember, using 208VAC with even 'just' 250amps service still gives you 52kw to play with. Plus, single phase service panels are cheaper than 3-phase ones.

Lastly, when powering all those PSU's the 3-phase feed would end up being split into into 3x single-phase circuits anyway but now with the added concern of needing to keep the load on each of the 3 circuits balanced (same watts per-leg). With single-phase, as long as you directly use the 208v and not split it into 120v circuits there is no balancing required.

THAT all said, I'd think that the co-op will want to know why a 'residence' is needing commercial amounts of power feeding it... They *do* have to maintain their part of the grid and make assumptions as to the kind of loads going on it. Commercial/industrial users pay more because larger grid infra is need to supply them.

Thanks for the reply. I'm thinking of at least 30-40 kw per day. Could you tell me the reason why going with 3 phase would be better?

It really depends on how much equipment you are running. If you are going for any kind of scalable larger setup you really should be running 3 phase power.

Hey all,
I'm looking to set up shop for a mining operation. The places that I'm considered are powered by a co-op which appears to charge less for residential rates than it does commercial. However, the only way to ensure a residential rate (as I'm told) is if you are using single phase electricity. For this reason alone, I'd like to go with the single phase but don't know enough about everything to make that decision based on just the price difference. Can someone please share with me the main differences of single phase versus 3 phase set ups as it effects BTC mining?
Thanks a bunch
MM33