[BackPlaner]

Hey y'all, I've got an Onyx with quite a few different boards to try out and I'm just wondering what are the minimum/maximum configurations to have it run off of 110v as opposed to 220v? (no 220 at our house...yet)

Did some googling but no luck..

[Irinikus]

It will definitely draw more current from the wall @120v!

With a 220v Power supply, I'm able to run my Max configured V880z and Tezro from the same wall socket simultaneously! (The V880z is a beast, with three 1175W power supplies!!!)

[BackPlaner]

Right, but a fully loaded Onyx with four R10K's and a full set of 64mb IR boards and several drives (for example) would need 220v, true?

[Irinikus]

Right, but a fully loaded Onyx with four R10K's and a full set of 64mb IR boards and several drives (for example) would need 240v, true?

Have you tried to run it on your 120v Power supply?

[hamei]

Right, but a fully loaded Onyx with four R10K's and a full set of 64mb IR boards and several drives (for example) would need 240v, true?

I've never had an Onyx so don't know how they are connected but generally speaking, no. It's all single-phase and there's no motors inside, so the difference is, say, 10 amps at 240 volts is equivalent to 20 amps at 120 volts. You just need much bigger wires at the lower voltage.

Think of it as a water hose (real electronickers will shoot me) ... either a small stream of water at high pressure, or a big stream at low pressure, but the force will be equal.

Anyway, that's the basic idea.

[BackPlaner]

Right, but a fully loaded Onyx with four R10K's and a full set of 64mb IR boards and several drives (for example) would need 240v, true?

I've never had an Onyx so don't know how they are connected but generally speaking, no. It's all single-phase and there's no motors inside, so the difference is, say, 10 amps at 240 volts is equivalent to 20 amps at 120 volts. You just need much bigger wires at the lower voltage.

Think of it as a water hose (real electronickers will shoot me) ... either a small stream of water at high pressure, or a big stream at low pressure, but the force will be equal.

Anyway, that's the basic idea.

Very good, thanks! Starting to understand why it comes with both options, electrical engineering was never my strong point.

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Right, but a fully loaded Onyx with four R10K's and a full set of 64mb RE boards and several drives (for example) would need 240v, true?

Have you tried to run it on your 120v Power supply?

I have, and it boots with the R4k x4 plus 16mb RE, but I wanted to do some more research before trying out the R10k x4 plus the 64mb RE in case something went boom. I've also got a gig of ram in it and I'm not sure if that adds to the power draw substantially.

[jpstewart]

I've never had an Onyx so don't know how they are connected but generally speaking, no. It's all single-phase and there's no motors inside, so the difference is, say, 10 amps at 240 volts is equivalent to 20 amps at 120 volts. You just need much bigger wires at the lower voltage.

Sure, but there are limits.  The Onyx deskside specs say that it can draw up to 16A at 110V or 13A at 220V.  The manual also lists a nominal rating of 1500 Watts at 110V or up to 2400 Watts on 220V.  In other words, when running at 110-120V the system cannot draw twice the current to supply the same total power. 

That appears to be due to the use of a 20A rated plug.  In North America (don't know about other locales) plug and socket connections are limited to 80% of the plug's rating by code.  80% of 20A is the 16A limit mentioned for 110V operation.  Now if you hard-wired it to a 30A circuit you'd theoretically be able draw enough power but might also burn out the Onyx PSU.  I don't know if it could handle that much current.  And certainly don't try it without consulting a licensed professional.  Normal household wiring is only rated for 15A!

[Dodoid]

Are you referring to a deskside or a rack? I always ran my deskside, quad R4K, two drives, two RM RE2, on 120V without issue.

[BackPlaner]

Are you referring to a deskside or a rack? I always ran my deskside, quad R4K, two drives, two RM RE2, on 120V without issue.

It's a deskside

[weblacky]

There is one thing I want to bring up to this discussion that people may be forgetting. Given the age of the device you're talking about, if you're going to switch such a huge power consuming device from 120v to 220v, you'll need to preemptively replace it's PSU High voltage side capacitors (caps). At least any caps on High-voltage side (the HUGE caps and any you see, like Mylar, before main transformer). Also any start caps and small stuff around the management IC would be also recommended (as it deals with RAW AC input in standby mode).

You see, a normal Switching PSU tends to create around DOUBLE the wall voltage in the large filter caps right off your rectifier. For 120v systesm they run about ~300v-360v (ish), when an you switch a PSU over to a 220v-240v style system, those old, tired, well worn to one single voltage only, caps are suddenly asked to carry much more voltage than they have been. This new, much higher voltage, (~450v +), is MUCH closer to the cap's actual original rating. Running a 600v cap at 300v gives you a huge wear margin, you've now lost most of the margins if you double your voltage (to lower your amperage, Ohm's law).

So there is a high likelihood you'll wind up with smoke and other not nice sounds coming from your SGI if you just plug it into a 220V outlet and turn it on, because the aged components cannot run that close to their original specs after 10+ years of 120v. The 120v was running them massively derated, 220v would be running them only minimally designed (from fresh) derated. I'm not trying to dissuade you from going 220v (there are perks). But doing the switch without doing a large cap replacement is gambling. Ideally, refreshing the whole PSU would be great, but if you at least put brand new (high-end) AC filtering caps and any caps before the transformer. You'll have a very high likelihood of successfully making the voltage transition just fine. If you don't change out those HV side caps, the wear and age on them may be unable to contain a doubling of the high wall voltage.

Just a fair warning, I've seen postings from other people on similar experiences getting a 120v system and plugging it into their country's 220v system and blowing the power supply due to age. It's supposed to work, when everything was fresh and new. The LV parts shouldn't (maybe) be affected too much by the increase in voltage, if they are working now, they are likely to work on 220v. It's the AC-Input side that will double, the frequencies used by the PSU switching mechanism will change switching rates so the same basic thing comes out of the transformer to LV side.

Better to refresh a working PSU, then a blown PSU.