What is a good place to buy telecom rectifiers and inverters? - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 27, 2016, 09:55:59 pm
content: I've been wanting to switch my server backup system to a dual conversion 48v setup for a while, but I find it really hard to find the equipment for that. Sites either want you to call for a price, or don't even offer that. "This is our product, look at it, it's nice, it has all these features!" with no option to actually see the price or buy. Basically I need 2 or more 48v programmable rectifiers, they would run at a set float voltage, like 54v and the units would be hot swap. I don't need more than like 2kw but I want it expandable. I did find some TDK-Lamda 1U rectifier shelves + supplies themselves on Newark though. So that's a start.Also need at least 2 120v pure sine inverters, that can put out 1500w or more. Idealy 2400w as that is what my PDUs are capable of carrying.I find random stuff on Ebay and what not, but I don't really trust that for something I would rely on for 24/7 operation.Anyone know any good sites to buy stuff like that? They'd have to be able to ship to Canada. I don't really have the money for it (I figure it would cost me at least 3 grand) but I want to start looking. I'm even toying with the idea of just designing and building my own PSUs, but I'm not good enough at electronics yet and rather rely on something from a company that has the experience. Not to mention they will probably be more efficient than anything I could make.Had a UPS issue the other day because it did not trip fast enough when I turned power off to my house and my file server hanged, and I don't want to go through that again. I got lucky in that there was minimal corruption but it was quite a pain getting everything back up. A dual conversion setup would be a safer bet to deal with all sorts of power outages, even really dirty ones.

author: uncle_bob
author_rank: Unknown
timestamp: May 27, 2016, 10:36:21 pm
content: Quote from: Red Squirrel on May 27, 2016, 09:55:59 pmHiAs soon as you say "telecom" you move into a world that sells things a truckload at a time. Most (if not all) of the outfits in that arena have interesting policies. Things like "minimum of 10 pieces" or "minimum $40K per year" or "single shipment total > $20K" are really common. That's on top of a price curve that sells the minimum number of pieces for 10X the volume price. (Truth in lending - I work for a company like I am describing.)Where to get the same sort of stuff from people that would love to deal with you? Look up "solar energy / off grid" on Mister Google. There are an enormous number of outfits that will sell you a 48V stack of batteries, the chargers, and the pure sine inverters.The difference between the solar stuff and the telecom stuff will be the various standards things are guaranteed against. Since you are not running a telephone central office ... not that big a deal.Bob

author: nctnico
author_rank: Super Contributor
timestamp: May 27, 2016, 11:06:00 pm
content: IMHO a better idea would be to just get a good PSU for that server which has some hold over time OR the UPS must be total crap.The problem with on-line UPSses is that the inverters also get to deal with all the rush-in currents at power on which they may not like.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 28, 2016, 12:21:41 am
content: Most common reason for a PSU being very sensitive to power issues is bad caps.

author: tautech
author_rank: Super Contributor
timestamp: May 28, 2016, 12:40:29 am
content: These guys used to do telcom power backup stuff under their previous trading name.http://www.innovative.co.nz/sectors/it-and-telecommunication/I see now they've some tie up with Schaefer.http://www.innovative.co.nz/schaefer-power-converters/Might point you in the right direction.

author: BradC
author_rank: Super Contributor
timestamp: May 28, 2016, 01:15:17 am
content: If you are dead set on dual conversion, just buy a second hand dual conversion ups. I picked up an mge pulsar 2200 for cheaps ($80) and a Liebert gxt2 3kva for nothing with just a bit of scrounging. Both full time dual conversion. Mind you, the ups(s) I actually use day to day are old APC Smart UPS and they do the job fine. Don't over think it or you will put a load of $ into a black hole that will turn into a maintenance nightmare. Just buy a good ups and swap the batteries out every 3-5 years.I've over-engineered here and have a nice APC rack mount ats between the ups and the pdu so I can swap out the ups without dropping the load.Also, what others have said. If you can't hold up for the 20odd ms a bad ups takes to swap over, your psu is toast.

author: uncle_bob
author_rank: Unknown
timestamp: May 28, 2016, 01:26:47 am
content: HiHere, until they swapped out the high voltage line to this side of town, we used to loose power every time the wind blew. Three outages in a week was doing well. Three to five a day was doing poorly. Most of them were seconds in duration, but plenty long enough to take down a computer that was not on a UPS. I have run a mix of devices from APC and Cyber Power. I also run a mix of computers ranging from Dell Power Edge servers to home built stuff to gear that still runs Windows 95. I never found a combo of UPS (of any brand) and computer that did not handle the outages. I *did* have a lot of batteries die. The cheap ones lasted for about two or three years. The more expensive ones lasted for three to six years.Sure am glad that tornado took out that stupid old line ....Lots of fun !!Bob

author: peter.mitchell
author_rank: Super Contributor
timestamp: May 28, 2016, 03:48:02 am
content: I've used a couple of ZTE ZXD-2400 before. Quite nice. Commonly available from .cn

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 28, 2016, 04:40:17 am
content: The point of this setup is also run time/expandability, so a regular UPS does not quite cut it, the UPS I have is actually an inverter-charger hooked up to marine batteries, though it's still like a UPS where it takes 16ms or so to switch over. 99% of the time it works fine, but clearly I must have got unlucky and hit the 1% that it didn't. The server PSUs are high quality hot swap units. I really doubt they are bad, though since they are redundant and hot swap I could easily take one out to inspect then inspect the other without bringing the server down again. I flipped the breaker on and off a bunch of times and it never happened again so this was a weird fluke. It took a bit of effort to throw the main and there was a bit of arcing, so I wonder if that was an issue, I've seen situations where there is a brownout and the UPS does not kick on fast enough. Common with laserjet printers plugged into the same circuit as the UPS (obviously not plugged IN the UPS, just along side it)I never thought of looking at solar stores, I actually do want to look at adding solar to the house at some point, so I could possibly look at a charge controller that also has commercial power capability to keep the batteries charged up.If I was to actually go the custom route, how realistic would it be to design a PSU that is like 90% efficient and will last long, for a newbie? Could that be achieved simply using a buck converter topology and high quality components? I'd probably build one design that's like 500w then just parallel them. I've been wanting to play around with making a bench PSU anyway, I may start with that to get a feel for it and go from there.

author: uncle_bob
author_rank: Unknown
timestamp: May 28, 2016, 07:45:41 pm
content: Quote from: Red Squirrel on May 28, 2016, 04:40:17 amHiOk, so design a power supply to replace what is in the server ... not so much. Stick with stuff that's easier to do.UPS trip point is not right for brownouts .... get one with an adjustable trip point *or* put in a cutout switch with a voltage monitor.Things go wrong every so often ... Consider that voltage can go up as well as down. If you have flakey power, you are likely to have voltage spikes. They will trip things. Having good spike suppression is the only real solution.Head over to the solar guys and see what they have to offer. Set up a double battery bank system and run the servers with dual supplies, one on an inverter on each bank.Bob

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 29, 2016, 02:46:41 am
content: I was thinking that too, maybe a huge contactor and a voltage monitor, if it detects any anomolity it just cleanly cuts the power, UPS then takes over. That or some kind of AC -> DC -> Inverter stage, I guess that would basically be an AVR? I could look into something like that. At very least I could put the most critical servers on it. Though something with batteries in between is best bet.If I don't find anything in the solar route I may indeed look at going the custom route, will make for a fun project, I'll start small scale, and go from there. But I'm thinking something with two large capacity charge controllers should do the trick. I don't have money for any of this now, so either way I won't do anything for a while but can at least start thinking about it.

author: uncle_bob
author_rank: Unknown
timestamp: May 29, 2016, 02:30:46 pm
content: Quote from: Red Squirrel on May 29, 2016, 02:46:41 amHiIf you are headed towards solar anyway (or even just thinking about it) the solar gear is the right way to go. They have all of the bits and pieces figured out. You can do a mix and match process to scale it to whatever level fits your needs. 2KW system ... can do. 100KW system ... got those as well. Solar / grid combo ... yup. Solar / grid / backup generator ... yup. Dual redundant this and that ... yup. Everything to DC and then take it from there ... yup. Much easier to get it all done safely than a full DIY approach.Bob

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 29, 2016, 05:43:57 pm
content: Quote from: blueskull on May 29, 2016, 03:07:41 amNoisy as in bad output or noisy as in audiable noise? If audiable it's going to be in the server room anyway. I know the Cordex ones we have at work are pretty quiet relatively speaking. (the AC unit drowns it out) There's like 40ish of em too. Big power! I'd need like... two lol.But yeah may start to look at the solar equipment route, but still have lot of time to think about this. My original plan was to do telecom style, then just inject the solar into the DC bus at a slightly higher voltage so that solar takes priority and rectifiers just fill in the rest. But may as well just get a charge controller that can do AC backup, and set it up without any solar, then add the solar to it later. Only downside is it may be hard to find rackmount solar charge controllers.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 29, 2016, 07:59:14 pm
content: You can get rackmount trays that are designed to adapt non rackmount equipment into racks. Also don't overlook the idea of tearing down an obsolete 1U server (free or super cheap) and reusing the chassis as a tray.

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 30, 2016, 09:39:28 am
content: Yeah I gave that some thought actually. If I feel confident enough to void the warranty of the equipment I could even take it out of it's case and place it nicely in a rackmount case and rewire any LCD, buttons etc to the front of the case. Idealy any controls such as voltage selection or off switch I would NOT want to be accessible front the front anyway.The custom route sounds kinda fun too though, once I get to a point where I am better at electronics design. I'll wait and think it over given I don't have much money now anyway. I'd also have to invest in some test gear if I do anything serious, like I'd definitely want a FLIR to check thermals over time and different loads, and maybe even a spectrum analyzer to make sure my design is not spewing off RF or something. So at that point it's probably easier to buy premade. Or an excuse to buy fancy test equipment...

author: uncle_bob
author_rank: Unknown
timestamp: June 01, 2016, 01:41:56 am
content: HiAnother thing you get with the telecom stuff is a design that is targeted at a 20 to 30 year lifespan. It also has at least a few years of testing and validation on it before the first unit i sold. This includes fun stuff like weekly conference calls with a few dozen people on them (for the same few years). Needless to say, if your volumes do not let you negotiate the price, this stuff adds quite a bit to the price. Yes it's weird that buying something already in production for 5 or 10 years still carries an IP cost with it, but that's the world of telecom gear. In reality, since the internal parts get harder to find, the price goes up and up on most of this stuff as time goes by.It's a strange world.Bob

author: Monkeh
author_rank: Super Contributor
timestamp: June 01, 2016, 01:56:28 am
content: Quote from: Red Squirrel on May 28, 2016, 04:40:17 amThat left side tower is nothing but batteries - 120 of them. None of this 48V stuff, either, they're centre-tapped 120V, and that gets boosted to 400-0-400V by the inverter modules. These particular ones go up to 18kVA.Have a good hunt around, these can go remarkably cheap (or free if you can take it away, sometimes..).

author: BradC
author_rank: Super Contributor
timestamp: June 01, 2016, 02:57:46 am
content: Quote from: Red Squirrel on May 28, 2016, 04:40:17 amRight, so it's not actually a ups. Just a power supply with a relay.Just to give you some ideas of the sort of things a real UPS does. Some use a capacitor discharge style of circuit on changeover relays to make them switch faster (like a 12v hold voltage and a 24V pulse to slam it over. I was surprised when I saw that!). Some maintain a continuous sinewave output in parallel with the incoming mains and just disconnect the incoming line when an anomaly is detected (APC SmartUPS do this). Some use ultra fast relays or bypass the relays with TRIAC's to handle the immediate switching load backed up by a slower relay (a lot of static bypass devices do this too).Then we get into the realm of full on-line UPS, where the load is powered by the inverter continuously and is completely isolated from the incoming mains by a rectifier/converter/battery charger.A UPS is actually designed to provide an output that will keep IT style equipment running under all conditions. An inverter/charger really isn't (unless it is supplying the load continuously, in which case you'd not have seen the problem you saw).As mentioned before, a *lot* of people/companies toss their UPS when the batteries die and replace it with a new unit that has a warranty. Most reasonable brand UPS's (ie APC, MGE, Eaton, Liebert) are good for several battery changes and can be picked up for cheaps if you sniff around. My main ups is 16 years old and still performs to spec.APC SmartUPS XL series are all designed to take external batteries. I have a Liebert GXT2-3000 and an MGE Pulsar 2200 here that both have external battery sockets. *That* will get you expandable extended runtime without farting around. Most APC SmartUPS SU or SUA series (3, 3.5 & 4G) can all be set to take external batteries, and if lightly loaded won't overheat with the factory cooling setup.