Topic: [ANN] Spondoolies-Tech - carrier grade, data center ready mining rigs - page 224. (Read 1260290 times)

What PSU is this?  Manufacturer?

but how to explain other three cables?

I would say that's very likely the main cause. While I can't comment with certainty without knowing more details on the cables and the pin arrangement, if you have a wire break on the circular connector the unit is then going to be trying to pull all the current through two (or one) pin on the Molex end. That's a surefire recipe for a burned cable.

got the PSU and miner today,PSU is still working, I found that the cables is came out from the PSU, so now I'm confused, why original cables can't take this amp?!
my another SP20 with same company's PSU and same cables just working fine!
https://i.imgur.com/VuBflrK.jpg
one pin is broke!!
but I think it is not the main cause
https://i.imgur.com/2D0HsQf.jpg
https://i.imgur.com/D23ihSQ.jpg
shit....
https://i.imgur.com/HQKoHiu.jpg

I like your plan.

"But honey its the perfect present for junior, and all the family"

My engineer put the SP20 through a tough quality test.  In the end he seemed happy.

Scam.
I wish - I'll buy SP31 from them instead of manufacturing...

I got the thing with 16AWG.

It's also because the plating is chemically applied  (I did some work for Molex in the past) .. and it's only 2 um thin. It goes away very easy, together with the contact rating just because of abrasion. Underneath is mild steel .. brass or bronze. Cheap stuff to allow the chemical reaction to take place.

It's funny to read though that Molex is making standards Very funny.

The Molex 45750 HCS+ connector which KNC mandates for Neptune and Titan use accepts 16 gauge wire and the Mini-Fit plus with these terminals is rated to 13 amps max.

What I find more interesting than this argument about how sane it is to pump 20kw thru one of these connectors is the Molex maximum insertion cycle specs. The tin plated connector is only good for 75. I assume this is due to the material fatigue that occurs and the resulting decrease in contact pressure between male and female pins. The select series are rated for 1500 cycles and the regular gold plated series for 100, so the maximum cycle limit must in fact be related to the thickness of material used to construct the terminal or its hardness rather than the plating material.

The terminals are manufactured so that you can have max wire of 18-20 AWG
http://www.literature.molex.com/SQLImages/kelmscott/Molex/PDF_Images/987651-0219.PDF

As per the PDF above Molex specifies 9A @ 600V, not at 12V. The max 18AWG cabling is good up to 16 Amps of chassis wiring. The 16AWG wiring allows 22 Amps of chassis wiring. These two estimates are based on nick-free soft annealed wire having a tensile strength of 37000 pounds per square inch.

Not sure if the terminals allow 16AWG though. As per spec, they don't. Those little guys do not have enough crossectional area (i.e. the wire is larger).

That is 3 x 9 x 600 .. as per molex specs if I meet all the constraints .. 16,200 W I guess 16A to 9A is derated enough.

If 16AWG can be used with these connectors my math tells me that 3 x 22 x 600 = 39,600 W .. even this one is derated enough down to 13A.

The rated ampacity is just a rule of thumb. In careful engineering the voltage drop, insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission for example, uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility.

Disclosure: I love 600V circuits. Everyone is afraid of them. Guess no one will buy a miner with such power requirements. What about a welder ?

Please see the comments I added to my last post wrt derating power connectors. I will give you that running one pair in open air with adequate airflow might be safe for a limited period of time. Just don't leave the power on overnight LOL.

The purpose of derating is to ensure safe operation under less than perfect conditions. Its good engineering practice, something KNC failed at BTW.

Your arguments remind me of the excuse KNC made when blaming a Titan customer for a connector meltdown -> "well you must not have had the connector plugged in straight".

Shameful really. A product should not be designed in such a way that it requires perfect operating conditions to be safe.

Actually, you can. The heat dissipated by a connector is a function of its current, not its voltage. It's not a transistor that has a SOA curve. The voltage rating is primarily a function of its insulation. Running them at the extremes of current is much more challenging that at the extremes of voltage, but even those current ratings are actually very safe with a couple caveats. The current rating is at a specific temperature, and with certain expectations as to the cooling capability of the board/wires as well as the condition of the contacts.. If your wires are running at extremely elevated temperatures and the board end is attached to power/ground planes that are at 80C, you might run into issues. Likewise if the connector has seen a lot of mate/dismate cycles or is dirty.

I will give you that running at 600V will probably give more spectacular results if a failure does happen, but that's a given working at the upper end of the low voltage range.

Obvious scam. They even include the mythical HashCoins Zeus miner, but the included picture doesn't match the Zeus.

LOL … be careful and don't turn your back on it or leave it overnight mate.

I can walk out to the garage and feel the heat coming off my Titan connectors and they are operated much more conservatively than your suggested maximum rating. Neptune owners have had similar problems at much lower ratings than 20kw …

Seriously you can not just take a max. voltage rating and a max amperage rating and conclude that the product is safe at the product of both operating extremes. There are lots of guidelines on connector derating to be found if you google around.
For example, reference 1 states that "Published current ratings in catalogs are often for a single contact pair isolated in ambient air.".
Reference 2 contains some connector derating guidelines in table 5 and related discussion.

1) http://powerelectronics.com/content/demystify-current-ratings-connector-selection
2) http://snebulos.mit.edu/projects/crater/docs/engineering/EEE-parts-derating.pdf

I suppose 600V 13A 3Φ would be enough? The output power would obviously be less (13.5kW), but peak voltage and current would be higher.

The price is too good to be true so it must be a scam. Will you please explain how come you created a user just to advertise the potentially scam site?

For everyone else reading this please do not order anything from the above site

Talk about OVERCLOCKING.

LOL... If I can figure out a 20kW load, I'll take you up on that. Why do you think the voltage makes a large difference in the current rating of the connector?

Anybody who thinks you can run 3 x 600v/13A circuits thru one of these little suckers deserves what they get