S4 Power Supplies & 277V

[altcointalk14]

I know this might create some controversy, but does anyone know how to modify the S4 PSU to run with 277V? 

I am running 277V on server power supplies, ATX power supplies, other ASIC Mfr power supplies and they all run rock solid on 277V even though they say INPUT of 120-240V.

When it is connected to 277V it will run for a few minutes OK, then red light on psu says fault.  If I wiggle the plug a little it goes back green and then fault.  Sometimes it will run for several minutes before it says fault.  Running on 240V it has no issues.

Thanks!

[Photon939]

You are most likely triggering the overvoltage protection circuit in the PSU. Not all supplies may have that feature. You must be very careful running PSUs on 277v as most power supplies use 400vdc rated input filtering capacitors and rectified 277vac has peak voltages of ~390vdc. Cheap PSUs may have lower rated caps that may leak or explode if run continuously on 277v especially if your line voltage is on the hotter side of 277.

Short of upgrading filter capacitors and disabling the OVP circuit there isn't a way to properly run them directly on 277v. (you probably don't want to do that)

Best way would be to get a transformer with taps that will get you down to 240v

[altcointalk14]

I am using 3 phase 480v service.  Single phase to neutral (or supplied ground) is 277Vac (actual measured value is around 272-274V).  I have a few grounding rods tied together for the PSU ground.  And I do have some 240V available, it is just easier to for me to add new 277Vac breakers, this will also slightly reduce the amps vs 240V.

OK, I have been warned.  Does anyone have instructions on how to disable the OVP?    (Only time I ever blew a psu doing this is was when the selector switch on the ATX PSU was on 110V)

Thanks!

[Photon939]

You would need to open the PSU and find the protection chip. Open the datasheet and see if you can find a way to disable only the voltage protection. This may involve lifting pins, adding wires or removing components.  Disabling the chip entirely would be a massively bad idea for obvious reasons. I don't recommend it either way.

The PSU has this feature for a reason; if it's tripping out now, bypassing it may result in catastrophic failure of the psu with a good chance of fire.

[Dalkore]

I am using 3 phase 480v service.  Single phase to neutral (or supplied ground) is 277Vac (actual measured value is around 272-274V).  I have a few grounding rods tied together for the PSU ground.  And I do have some 240V available, it is just easier to for me to add new 277Vac breakers, this will also slightly reduce the amps vs 240V.

OK, I have been warned.  Does anyone have instructions on how to disable the OVP?    (Only time I ever blew a psu doing this is was when the selector switch on the ATX PSU was on 110V)

Thanks!

You are creating a serious and real fire risk running the PSU higher than its input rating.  I would also not recommend it, get a transformer and do it right.   This is not being over cautious, real fire risk, I'll repeat it.

[QuintLeo]

Transformer, or bite the bullet and put the 220 circuits in to run it SAFELY, IMO.

 Way too high a probability of frying power supplies trying to run them that far outside their rated input voltage - and a significant chance of frying the equipment they are attached too when they die.

[altcointalk14]

Thanks for the warnings and reminders, I got it.

the manufactures website says max 264vac input, 277 is just under 5% more.  When these are engineered/designed they have a safety factor built-in and it should run fine on 277V.
http://aplus-powersupply.com/products/bitcoin_powersupply/bitcoin-miner-power-supply-ap188/

Here are pictures of the power supply.

http://imgur.com/a/LUURV

Ideally, I would just like to remove the over voltage protection, not the ground fault shutoff.

Anyone have any ideas to try?

[Dalkore]

Thanks for the warnings and reminders, I got it.

the manufactures website says max 264vac input, 277 is just under 5% more.  When these are engineered/designed they have a safety factor built-in and it should run fine on 277V.
http://aplus-powersupply.com/products/bitcoin_powersupply/bitcoin-miner-power-supply-ap188/

Here are pictures of the power supply.

http://imgur.com/a/LUURV

Ideally, I would just like to remove the over voltage protection, not the ground fault shutoff.

Anyone have any ideas to try?

No one responsible will recommend you do that, if you start a fire then it weigh on their conscious if you were hurt.  Just get a proper circuit installed.