Three wire in - three wire out into panel?

[mlewis_apc]

Hate to start a new thread but badly need an answer asap :).

I used to have a Powerware UPS which was replaced with a Smart-UPS RT 10000 XL.
The powerware used 4 wire input and 4 wire output. Even though the ground and common's are tied together at the utility box, I had to run two separate wires into the UPS. Then, on the UPS output, I had to run 4 wires out into the breaker panel, keeping common and ground separated.

Now, this replacement UPS has only three wire in and three wire out. The breaker panel and this needs to connect to has separated ground and common. So, this doesn't work of course, other than only one breaker working. Any other turned on creates a fault.

So, is the answer as simple as making a connection between the ground and common in that breaker box panel then I'll be fine?

Mike

[mlewis_apc]

this UPS only outputs 208 or 240 depending on what you input to it. you cannot split the lets and then >create 120v (hot, neutral, and ground) at the panel for output. this UPS does not have the split phase >technology to output two equal legs. to do this, you'd need something like a Symmetra LX to split the >two legs of input to two equal legs of output.

Ok, now I'm confused :).

I have it connected with 230VAC input from a 50A breaker on the utility panel. I then have the UPS output connected onto another panel, which is 230VAC input and breaks out 115VAC outputs.

So, after tying the ground and common together in the panel, which seems to work now, why is it outputting 115 to each breaker? Doesn't this mean it's working or Is this because it is in fact in bypass mode then?

It's LED says it's ON, and there is power to the breaker panel and 115 on each outlet and each outlet is running a test load item such as a light and expendable hardware. The problem is that when the ups goes on battery, it shuts down the load. The web interface says that everything is fine.

with this particular UPS, to get 120v, you need a step down transformer such as one of the items >seen at this link. the APTF10KT01 may be your best bet, assuming i understand you correctly.

So, now I have to find step-down devices to actually get 115VAC from the unit? And this means I won't be able to use the panel I have then?

Mike

[mlewis_apc]

So I tied ground together and that seems to be fine now. I can turn on multiple breakers. Each breaker is a 15AMP by the way.

But, there's something weird going on.

Any time the unit goes on battery mode, it turns off the load until it goes back to utility, then switches the load back on. The batteries are fine according the tests and LED's so am not sure what's going on now. The bypass switch is not on either.

The web interface says that everything is ok but, it's not.

[BillP]

this UPS only outputs 208 or 240 depending on what you input to it. you cannot split the lets and then create 120v (hot, neutral, and ground) at the panel for output. this UPS does not have the split phase technology to output two equal legs. to do this, you'd need something like a Symmetra LX to split the two legs of input to two equal legs of output.

with this particular UPS, to get 120v, you need a step down transformer such as one of the items seen [at this link|http://www.apc.com/products/family/index.cfm?id=170]. the APTF10KT01 may be your best bet, assuming i understand you correctly.

[BillP]

okay..so where did the 230v come from? 😉

honestly, it sounds like something going on with the wiring. ideally, you should be using the step down transformers as i mentioned because the legs arent split equally as we've discussed/noticed so you shouldnt have a 120v panel directly from this unit. once you get the stepdowns, we can see what happens as far as output so we can rule out the wiring. i dont think theres anything wrong with the UPS at this point.

if you have any questions, let me know or i'd be happy to work with you directly on the phone while setting these up if you need assistance.

[BillP]

if you measure the output from the wiring block on this particular UPS, which I have done while inputting 208v, you should see ~160 on one phase and about ~50 on the second phase, then between both phases 208v. as I mentioned, this unit doesnt have split phase technology so it only cares that the measurement of voltage between the phases is correct, so in my lab, it is 208v but the two legs do not equal 120v.

i cant say i am an expert on the electrical wiring in a panel, but i guess if the panel generates a neutral for your 120v equipment, that'd work but the UPS doesnt have a neutral since its a three wire input. that is what stepdown transformer would do is step down the voltage and generate a neutral.

in regards to the load dropping, when it goes to battery, are you measuring any voltages out of these outlets? the measurements you receive through the UPS, should be the same while online or while on bypass with this particular situation with the output voltage readings via voltmeter. you said the web interface reports its online correct? what happens if you command it into bypass, rather than putting it to battery? granted, this MAY drop your load again depending on what is going on so maybe you'd want to try it with a non-critical load to avoid an unnecessary load drop.

[mlewis_apc]

I didn't think to check the voltage on the breaker panel because I was only testing a couple of circuits being turned on. Using the web interface, if I put it into bypass, I get the following;

The UPS did not accept the command. There might be a problem with communication to the UPS. >Check the current state of the UPS and try again.

Mind you, I just turned it on a few minutes ago to run this test, from remote, using the web interface.
Turning it off/on works, rebooting it made the load go on and off, putting it to sleep didn't turn the load off. Simulating a power failure, the load went off, then back on.

Putting it in self test, I saw the load go off, then back on. Everything always says it passes. So, all tests but bypass seem to work.

I've got a lead on two SYTF2 step-down transformers so I'll see if I can get these on their way to me tomorrow as I badly need to get this thing working. I'm still a bit confused about the output going on and off though.

My concern is that something is wrong with the UPS however.

Mike

Message was edited by: mlewis

[mlewis_apc]

This editor is a bit confusing :). Anyhow, I'll re-post the stats.

I may have used the term 230VAC meaning two legs of utility. I say 115VAC and 230VAC when referring to the utility since that's what the legs seem to put out if I recall. Either way, it's MN so it's US power :).

Everything seems to be fine from the web interface but obviously, not at the output. I didn't think of testing the voltage because of this.

Mike

Message was edited by: mlewis

[BillP]

hi mike

a couple of things i want to mention/confirm:

1.) can you confirm the exact model number on this UPS? we need the model off the white sticker on the back or behind the front bezel. it should begin with SURT.

2.) you mentioned you are feeding the UPS with a 230v 50 amp feed. this is not the recommend configuration per the [user manual|http://www.apcmedia.com/salestools/ASTE-6Z8LVK_R4_EN.pdf]. please review this manual after confirming your model number. XLT is a domestic model and XLI is an international unit (which usually is fed 230v). also make sure you are using the proper AWG.

3.) can you provide the following measurements while the UPS is both online and in bypass from both the input and output? if you have physical access to the unit, there is a bypass switch on the back of it since the software isnt working.

L1-G:
L2-G:

there may be a potential wiring problem here so we want to make sure we sort that out. we could be seeing a problem such as a ground loop causing the load drops.

[mlewis_apc]

Ok, the SURT is SURT10000XLT
And doing the voltage test was interesting.

Input: 200/208VAC
Output 200/208VAC

Online and in bypass mode, both the same output at the panel. The panel has ground/neutral tied together.

93VAC on one leg and 120VAC on the other leg.
Testing both hots gives 213VAC average.

Again, this building has ground/common tied together at the utility box. My thinking was that since this is a three wire unit, so long as my three wire connections are ground or neutral and the two hots, that things should be fine.

Mike

[mlewis_apc]

Everything seems to be fine from the web interface but obviously, not at the output. I didn't think of testing the voltage because of this.

Utility power status

Input Voltage: 243.3 VAC
Input Frequency: 59.99 Hz
Maximum Line Voltage: 243.3 VAC
Minimum Line Voltage: 239.0 VAC

Output power status

Output Voltage: 208.2 VAC
Output Frequency: 60.03 Hz
Load Power: 000.0 % Watts
Apparent Load Power: 000.0 % VA
Load Current: 00.00 Amps

Battery status

Battery Capacity: 100.0%
Battery Voltage: 218.1VDC
Number of External Batteries: 001
Self-Test Result: Passed
Self-Test Date: 04/17/2009
Calibration Result: Invalid
Calibration Date: 04/16/2009

Message was edited by: mlewis

[mlewis_apc]

Utility power status
Input Voltage: 243.3 VAC
Input Frequency: 59.99 Hz
Maximum Line Voltage: 243.3 VAC
Minimum Line Voltage: 239.0 VAC

Output power status
Output Voltage: 208.2 VAC
Output Frequency: 60.03 Hz
Load Power: 000.0 % Watts
Apparent Load Power: 000.0 % VA
Load Current: 00.00 Amps

Battery status
Battery Capacity: 100.0%
Battery Voltage: 218.1VDC
Number of External Batteries: 001
Self-Test Result: Passed
Self-Test Date: 04/17/2009
Calibration Result: Invalid
Calibration Date: 04/16/2009

Message was edited by: mlewis

Message was edited by: mlewis

[mlewis_apc]

The problem is that this started on a tight budget to begin with. I was lucky to buy this used and need to find a solution. I wish I had the budget to just run out and buy what I needed right now but I don't so need to solve this somehow with what I can.

Is there any way at all that I can make this thing work without the transformers? For example, it's putting out one leg which is the proper voltage. Would it be possible to use just the one leg for now, until I can find/buy the step-downs I need?

Also, would 208VAC UPS's work with this? I may have a couple of 208VAC UPS's which have 120VAC outlets on them.

And, just to make sure I don't pop something... the outlets on the unit are four 208VAC out right. These are standard AC outlets, which I could plus, say an IBM BladeCenter into?

Mike

Message was edited by: mlewis

Message was edited by: mlewis

[BillP]

ok, right off the bat i see a problem. it is not good practice to be inputting 240 volts to this and output 208 volts. that is why it wont let you put it in bypass i think which passes your 240v to your equipment but when the UPS is online, its outputting 208v. some equipment cant handle that but it sounds like yours can i guess.

i cant recommend only using the one leg of 115 or 120. it may fluctuate and it also may switch legs as to which one outputs around 115. i wouldnt risk it. some of our UPSs are configurable for 208v or 240v, like this one. the regular Smart UPS (not Smart UPS RT like this one) can only do 208v for the most part and will constantly be in trim mode if you input 240v to it which is what it looks like you have at this site based on what you posted. it is not recommended to have the UPS trimming constantly since it will create a lot of heat, will constantly tell you its trimming via software/emails/front panel LED, and will probably degrade the life of the UPS as well as the battery because of the extra heat it will cause. if you let me know what model you have, i can confirm or deny this for you though just incase you do have a model that will work.

the outlets for 208v and 240v are the same - L6-20R or L6-30R i think on this UPS. i think you should find out exactly what your equipment requires (208v or 240v or either) and then you should think about changing your output on the UPS to 240 to match your input. as i mentioned, its not good practice to do what you are doing. also, except for a couple of exceptions, if you output 240v from the UPS, majority if APC's step down transformers will output ~136v and not ~120v because they expect an input of 208v and not 240v so there arent enough turns in the transformer to get it down to 120v. [SYTF2|http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SYTF2] requires 208v so if you pass 240v to it, it will output ~136v. now, when the UPS is online as you have it right now (outputting 208v), thats not really a problem. when you go to bypass, the UPS will feed the 240v through and then that is when you will see the problem.

let me know if you have any questions!

[mlewis_apc]

ok, right off the bat i see a problem. it is not good practice to be inputting 240 volts to this >and output 208 volts. that is why it wont let you put it in bypass i think which passes your

The voltage in MN seems to be 120/240, based on my testing. The average is actually around 117VAC or so. The manual seems to say it will accept 200/208/220/240 VAC input.

The Utility power reading from the web interface is;

Input Voltage: 243.3 VAC
Input Frequency: 60.01 Hz
Maximum Line Voltage: 243.3 VAC
Minimum Line Voltage: 239.0 VAC

What's interesting is that on the Utility Line Settings, the voltage option goes up to 250VAC as the Bypass Upper Voltage. Doesn't this mean it is a 240VAC machine?

240v to your equipment but when the UPS is online, its outputting 208v. some equipment >cant handle that but it sounds like yours can i guess.

I don't have anything connected to it just yet, just some test hardware that is expendable, a light, an old hub, etc.

i cant recommend only using the one leg of 115 or 120. it may fluctuate and it also may >switch legs as to which one outputs around 115. i wouldnt risk it. some of our UPSs are

I didn't think so but thought I'd ask :).

the regular Smart UPS (not Smart UPS RT like this one) can only do 208v for the most part >and will constantly be in trim mode if you input 240v to it which is what it looks like you have
at this site based on what you posted. it is not recommended to have the UPS trimming

It appears to be putting out a solid voltage though but you're saying this is not an adjustable unit? Here's what I see in the web interface if it'll help.

Utility Line Settings
Output Voltage: 208 VAC
Bypass Upper Voltage: 229 VAC
Bypass Lower Voltage: 146 VAC
Output Frequency Range: Auto Hz

Doesn't seem to be much for adjustments unless it's done in another way.

battery because of the extra heat it will cause. if you let me know what model you have,
i can confirm or deny this for you though just incase you do have a model that will work.

Do you mean what I've posted or something else? It's a Smart-UPS RT 10000 XLT.

you should find out exactly what your equipment requires (208v or 240v or either) and
then you should think about changing your output on the UPS to 240 to match your input.

It's all computers, servers, storage hardware. It usually allows for fluctuations +/-. I was using a Powerware Plus 12/12 for the longest time, which was 240 in and 240 out. Since then, I've been using multiple Smart-UPS 3000 non RT units. Everything works fine on those, if that says anything.

as i mentioned, its not good practice to do what you are doing. also, except for a couple
of exceptions, if you output 240v from the UPS, majority if APC's step down transformers
will output ~136v and not ~120v because they expect an input of 208v and not 240v so

I'm not really doing anything with the unit yet, other than discovery in this forum, to see how/if I can get this to work so nothing lost right now. The hardware is currently on those multiple 3000's which I wanted to replace with this one unit.

if you pass 240v to it, it will output ~136v. now, when the UPS is online as you have it right >now (outputting 208v), thats not really a problem. when you go to bypass, the UPS will feed >the 240v through and then that is when you will see the problem.

I'll do a little more voltage testing and see what I come up with and post my findings.

Mike

Message was edited by: mlewis

[mlewis_apc]

I'm rather confused at this point :).
The manual seems to say that this unit, the XLT, which is what I've got;

Input & Output - 200/208/220/240 V
And again says further down in the manual;

XLT models Output Voltage : 200, 208, 220, 230, 240 VAC

Are we talking about the same machine? I do see that on the APC site, there is another of the same model which does say 208? However, even it mentions;


Nominal Input Voltage 208V
Input Frequency 50/60 Hz +/- 5 Hz (auto sensing)
Input Connections Hard Wire 3-wire (2PH + G)
Input voltage range for main operations 160 - 280V
Other Input Voltages 240

Other input voltages?

Message was edited by: mlewis

[BillP]

yes we are talking about the same machine. for domestic use in the USA, the voltages you can use are 208v or 240v for the most part. dont worry about what the manual says because the fact of the matter is that you have 240v at your site.

you are seeing:

Input Voltage: *243.3 VAC*
Input Frequency: 60.01 Hz
Maximum Line Voltage: 243.3 VAC
Minimum Line Voltage: 239.0 VAC

so you are inputting 240v to this UPS. what i am trying to say is that you have 240v at your site based on the info above. 240v and 208v are NOT the same voltage. with your current configuration you are inputting 240v to the UPS and outputting 208v which is not recommended. you should be inputting AND outputting 240v if thats what is available at your site. if you go to bypass for some reason, the equipment will receive 240v instead of 208v like when the UPS is online. that is a difference of 38v. some equipment may not mind that or some may get damaged, depending on what it is and how sensitive it is to voltage fluctuations.

let me know if that makes sense.

[mlewis_apc]

Yes, this makes sense.

So, there is no way of configuring this machine to do what I need then?
And if so, what are my options at this point?

[BillP]

well what do you need? can your equipment be fed 240 or does it require 120? if you want to stepdown 240v to 120v, you can use a SURT003 with this UPS or a APTF10KT01 stepdown no problem. either SKU can stepdown 240v to 208v successfully. the APTF10KT01 has a hardwire output for you to use with a subpanel.

[mlewis_apc]

The hardware is all sorts of computer hardware, servers, storage systems, all seem to handle a range of voltage for US use. I'm in MN if that means anything so what ever standard voltages are, utility grade, that's all I need.

Earlier in the thread, it seemed to be a problem to step down so am a bit confused right now. The only 240VAC hardware I have is a large blade server, the rest is all 110/120VAC or US grade if that means anything. Sub-panel output would be the best but if all I can get is 110/120VAC, that's fine too.

Message was edited by: mlewis

[BillP]

yeah i would say a couple amps is fine. i just feel its a waste to buy a $600 transformer for this particular scenario 😕

and you are right, SURT003 isnt able to support up to 10kVA.

[mlewis_apc]

I think what is confusing me is that all of my hardware is standard hardware, which should run anywhere in the US.

It should be able to handle what ever variations there may be between different areas of the country. I am not running anything special, standard computers, servers, storage, which could run anywhere unless there are some areas of the US which are very different from others.

When you ask me what my hardware needs specifically, I can't tell you exactly other than it's all standard US power so one would think, what ever low/high there is in the US?

Took a quick look and here's what many of the items have as an example on their stickers.

100/120
100/127
100/240
115/120
120
~120
120/240
170/264
200/240

Message was edited by: mlewis

[mlewis_apc]

with your current configuration you are inputting 240v to the UPS and outputting 208v which is not >recommended. you should be inputting AND outputting 240v if thats what is available at your site.

Can you explain this a bit more. I'm not actually doing, anything :). I just hooked this UPS up to power so far, I've not configured it or changed any settings. If it's putting out 208, then that's what it was previously set for. I've not changed any settings, yet.

Now, on that note... you say "you should be inputting AND outputting 240v if thats what is available at your site" so, are you telling me that this machine can be configured to do this? Earlier in the thread, someone said that this machine cannot do this.

Since then, I've asked about step-down transformers, which also didn't seem to be an option but in a message before this one, you mentioned that there IS a step down option, in fact, a couple, which would give me what I need?

The person I bought it from says;

This was used to power a Cisco 6509 and rack of Cisco routers and switches.  The unit is designed >for voice and data networks.  The general description on the unit is listed below.

Mike

Message was edited by: mlewis

[BillP]

Can you explain this a bit more. I'm not actually doing, anything . I just hooked this UPS up to power so far, I've not configured it or changed any settings. If it's putting out 208, then that's what it was previously set for. I've not changed any settings, yet.

see my screenshot. you want to go to this screen (which I know you mentioned it before) and you should be choosing an output of 240v instead of 208v, like it says now. you are right - out of the box, this UPS by default is set to 208v. if you want to use it in a 240v environment as you are, you need to specifically come into this section of the management card and change it.

Now, on that note... you say "you should be inputting AND outputting 240v if thats what is available at your site" so, are you telling me that this machine can be configured to do this? Earlier in the thread, someone said that this machine cannot do this.

i am not sure if there was confusion or something but with this UPS, you can definitely do this..this particular UPS in the states should be running on 208v or 240v.

Since then, I've asked about step-down transformers, which also didn't seem to be an option but in a message before this one, you mentioned that there IS a step down option, in fact, a couple, which would give me what I need?

The person I bought it from says;

This was used to power a Cisco 6509 and rack of Cisco routers and switches. The unit is designed >for voice and data networks. The general description on the unit is listed below.

now that we know your configuration, i can confirm that since you are inputting 240v and are essentially wanting to get 120v to your equipment, yes you have two options for step down transformers that will take 240v and give you 120v. those two SKUs are SURT003 and APTF10KT01.


based on your prior post to this one, you should be just fine with either step down transformer, the only problem is SURT003 does not have a hardwire connection so you cant wire it to your panel. the APTF10KT01 has a hardwire output so you could hardwire it to the UPS output to the stepdown input and then from the stepdown output to your panel.

you may have some other options as far as [Rack PDUs|http://www.apc.com/products/category.cfm?id=6&subid=48] depending on what type of plugs you have on these servers but it sounds like you already have existing wiring/outlets which is what you want to use.

[mlewis_apc]

You won't believe this but I'm stopped again :).

There is no section to change the output as in your image? I've posted the firmware this is running as it's definitely different then the image you've posted.

I don't seem to have any option to change the output. Mine says;

Output Voltage: 208 VAC

But there's no box to change anything, it's just static for that line. The others do have boxes and options and are currently set to;

Bypass Upper Voltage: 229 VAC
Bypass Lower Voltage: 146 VAC
Output Frequency Range: Auto Hz

Here is the information I can see;

Model: Smart-UPS RT 10000 XL
Firmware Revision: 476.13.M
Manufacture Date: 12/13/04

[BillP]

i have an SURT10000XLT:


Model: Smart-UPS RT 10000 XL
Position: TOWER
Serial Number: YS04******
Firmware Revision: 476.12.M
Manufacture Date: 04/23/04

we could also see if we can change this setting through hyperterminal but i am not sure why you cant see this drop down list in the section in the screenshot i posted.

[mlewis_apc]

I've updated the firmware so will know in a few minutes, perhaps the option will now show up.
Whew, one thing after another. Now I've got to go hook up a cable because I can't telnet in either.


Error: The application was not able to load.
You are attempting to access an APC device.
There was a problem loading the application. Please login to the device via telnet for more details.

Back shortly, suspect update turned off remote access.

Mike

Message was edited by: mlewis

[mlewis_apc]

Wonderful, that worked! Now the web interface does indeed show 240VAC as an option so I've set it.
Now that it's going to be putting out 240VAC, does this mean I'll be able to use it with my panel after all?

Also, what should the upper/lower bypass voltages be for 240VAC input?

Update: It changed itself once it took the 240VAC setting, to Upper=264 and Lower=168. Should I change those settings or are those optimum?

Now I get 119VAC on one leg, 127VAC on the other so even if that's not 120 on both legs, it's closer. I think you said I'll still need step-downs however.

Mike

Message was edited by: mlewis

[mlewis_apc]

So if I'm still going to need step down's, I've come across two SYTF2 locally. They seem to allow for 208/.240 input with 120 output.

So, hope you'll tell me these will work!

Message was edited by: mlewis

[BillP]

😞 going by [this users manual|http://www.apcmedia.com/salestools/ASTE-6Z3QG7_R0_EN.pdf] it only notes 208v for this model (SYTF2) so i think you will get about 136v output. where did you see it could handle 240v?

i am glad upgrading the FW worked for you. easy fix at least.

so yes, now the UPS is outputting 240v but still not equal legs of 120v as you can see. but as you figured out, yes technically you should use step down transformers because we cant guarantee the output will always be 120v and 127v, it may fluctuate and the load wouldnt like that.

[mlewis_apc]

The PDF manual I'm looking at says that the SYTF2, using 208VAC input, will output 120VAC/60Hz. The manual is called;

APC Step-Down Transformer
Models: AP9621, SURT005, SURT006, SUTF3, SYTF2, SYTF2J, SYTF3 and SYTF3J
Users Manual - English

So, since I can in fact use 240VAC as input to the UPS, and change it's output back to 208VAC, I should be able to feed the SYFT2 which would give me 120VAC.

I'll be using two of the STFT2 units. Is this all coming together now? :).

Mike

[BillP]

hi mike,

as we went over several times before, it is not good practice to do input 240v to the UPS and output 208v because when you go to bypass, the UPS will feed the 240v through its output to the step down transformer and this model of step down transformer cannot step 240v down to 208v. you will get an output of about 136v.

so yes, you can do what you are looking to do but i cant recommend it for the reasons we've discussed in this thread prior dealing with bypass and just general electrical practice.

[BillP]

you're right. i dont think the Network Management Card will allow you to command it in bypass via the NMC because of its logic and seeing the voltages out of range, but you can still put it into bypass via the physical switch on on the back of the UPS.

[voidstar_apc]

>
PS: You mentioned firmware updates, guessing that's because the unit reboots? So does this mean that reboots would also drop the load then? Those things aren't so bad, so long as I can get by with this machine for a while, that would sure help the budget.
>

You're probably thinking of the Network Management Card. That's a separate firmware... nothing you do to the network management card including reboots or firmware upgrades should cause the load to drop. Unless you explicitly command it to turn off power. I only mentioned the UPS firmware issue because some of our UPSes have upgradeable firmware and that requires going to bypass. Chances are, you would never upgrade the firmware on your UPS even if it has the capability, because we like to get the UPS firmware right the first time 🙂

[mlewis_apc]

Keep forgetting about that bypass issue. Guess I'm sunk them, not much more I can do unless there is some way that I can convert the 240 input to the UPS to 208 before it even reaches it, in some inexpensive way.

Mike

[mlewis_apc]

Let me make sure there's no confusion if you don't mind.

The UPS can accept 240VAC input, and can output either 208VAC or 240VAC.
However, in bypass mode, it can only output 208VAC.

So, I'm not clear on where the problem is then.

The step-down units take 208VAC input and put out 120VAC output.

Why can't I simply leave the UPS in 208VAC output mode? I'm not going to be using a panel or breaker box, I'm only going to have the step down units plugged into the outlets on the UPS. So when the UPS goes into standby mode, if I have it set to 208VAC output, won't it simply continue to put out 208VAC?

Mike

[BillP]

no, it will not. in bypass mode, the UPS bypasses the inverter which outputs the UPS power and feeds utility power through to the load.

so, if you have 240v AC power, when the UPS is online and set to 208v, yes, your set up will work perfectly fine. if you have 240v AC power and the UPS goes to bypass, the 240v will be fed through the UPS and the UPS will just simply act as power outlets and will not be adjusting the voltage at all and will NOT provide any battery back up power.

does that make sense? so this will work fine in online mode if you set the UPS to output 208v but when the UPS goes to bypass, your 240v will go straight to the output.

[mlewis_apc]

I know I'm using wrong terminology in some places which I'm guessing is what is causing the confusion.

I understand what you are saying, that when the UPS goes into bypass mode, the utility 240VAC will then hit the load, instant jolt from 208VAC to 240VAC, not good.

However, is bypass mode the same as battery mode? And does Online mode simply mean the UPS is now in the mix or is that when the UPS is on battery mode? If bypass mode and battery mode mean two different things, then there's still a shot here.

This would mean that I would have to be careful about never putting the UPS into a bypass mode setting, which I'm not sure is even possible, based on various scenarios but perhaps you can confirm this.

So, here's another thought... could I use, say another step-down, in front of the UPS? What if I had a step-down from 240VAC >208VAC between utility and the UPS? Then I could not accidentally put 240VAC out as it would all be 208VAC.

If this can be done, am I using up a lot of my circuit at this point just feeling the first step-down, then the second one? If not, then that would be my simple solution since I can't run out and buy another UPS today.

Mike

[voidstar_apc]

If the UPS failed and went into bypass, it would just feed the 240V to your equipment. No "massive spike beyond 240VAC".

Chances are, things would just run a bit hotter. Power supplies tend to be tolerant of overvoltage situations, such as feeding 240V into something that takes 208V, or feeding 139V into a 120V unit. But of course we don't make that equipment, so we can't guarantee their behavior.

[voidstar_apc]

>
so, if you have 240v AC power, when the UPS is online and set to 208v, yes, your set up will work perfectly fine. if you have 240v AC power and the UPS goes to bypass, the 240v will be fed through the UPS and the UPS will just simply act as power outlets and will not be adjusting the voltage at all and will NOT provide any battery back up power.
>

Does the UPS even allow this? I would've thought since the input voltage (240V) is not within the bypass range around the output voltage (208V), the UPS would not allow itself to go into bypass. If that's the case, the only thing he loses is protection from dropping the load if something goes wrong with the UPS, and if the SURT supports firmware upgrades, the ability to do that without dropping the load.

[mlewis_apc]

So, are we saying I'm good to go, so long as I never put it into bypass mode?
Otherwise, there isn't any reason why it would go into bypass? Either online or batteries, and either would keep 208V going?

Of course, when and if I ever need to take the UPS down, then I need to plug the load into another UPS or source first. And, this was all about being able to use my generator which also puts out 240VAC so, that will match the setup at least. It's about 30 seconds before the transfer switch flips between utility and geny.

PS: You mentioned firmware updates, guessing that's because the unit reboots? So does this mean that reboots would also drop the load then? Those things aren't so bad, so long as I can get by with this machine for a while, that would sure help the budget.

Mike

[mlewis_apc]

Sounds like it'll all work out now?

I feed the UPS 240VAC but keep it set to 208VAC output.

I'm not using a breaker panel after all but plugging two step-down transformers into two of the outlets.

The step-down's are 208VAC input and 120VAC output outlets.
I'm hoping to use two more of the outlets to power an IBM BladeCenter directly.

When the UPS goes into battery mode, it will continue to output 208VAC.

Manually putting the UPS into bypass mode is the only way that the load would suddenly get 240VAC from utility, otherwise, everything is fine.

Anything overlooked?

[BillP]

if the UPS goes into failure bypass, that would be another situation where it would feed through the 240v - so if the UPS fails and it cannot be online anymore.

bypass is more useful with larger modular units when you need to remove modules, etc but in this unit, the UPS goes to automatic bypass when replacing the batteries and also as i mentioned, if there is a failure, or also when there is an extreme overload and the UPS cant output enough wattage from its inverter. also, this UPS requires you to go to bypass to remove and reinsert the network management card (to avoid damaging the card).

[BillP]

by george, i think we've got it!

[mlewis_apc]

You just knew I'd want to say it twice, just in case because, I certainly don't want to blow any of my hardware up.

To confirm, there is no way, it will bolt to 240VAC output to the load other than in bypass mode. And since I won't be putting it into bypass mode, this should not be a problem.

By the way, what are some of the reasons one would want to put it into bypass mode? I mean, if the power is still going to run through the device, why would this be a required mode?

[mlewis_apc]

Looking at the docs, looks like it only handles 4500KVA or such. Guessing I would need at least 8/10KVA if it were being used in front of the UPS.

Either way, you don't really feel it's needed then? Even better if that's the case.

And when you say as long as the load is static, would a couple of AMPs either way be acceptable? Things seem to change by a few AMPs constantly.

Mike

[mlewis_apc]

Maybe I can keep an eye open for a step down unit which might handle the 50AMPS (or was it 40?) that the UPS requires. This way, I could avoid all of these problems.

if the UPS goes into failure bypass, that would be another situation where it would
feed through the 240v - so if the UPS fails and it cannot be online anymore.

Any thoughts on what I can expect if this were to happen? Is most computer hardware fairly resilient to this type of spike? I guess I'm asking what the chances are of most things surviving should this happen.

also when there is an extreme overload and the UPS cant output enough wattage from
its inverter.

Any chance you could give me some example of this? What might an extreme overload be for this type of UPS? And/Or, at what percentage of load do you think I should keep it to be safer? My current geny puts out only 50AMPs so I can't load this UPS up too much. I don't want it to switch between utility and geny if the geny can't keep up. Guessing that's what would happen? Now that would be very bad, switching over and over? Is that what would happen and any way of preventing it?

Pretty much everything on this network has dual power supplies. If this, the main UPS does fail and sends 240VAC to the load, at best, one of the power supplies will fail, making the assumption that it's not going to do something crazy like sending the load some massive spike beyond 240VAC.

The things you have to do when you're on a budget sometimes. It's so easy to say 'isn't it cheaper to buy a new UPS than to lose your hardware?'. And the answer would be no. We don't have the budget to do this as we'd like to which would be a new UPS, a new geny, etc. We do have a heck of a lot of spare hardware which can take over if things go wrong. So if I can make this last for a year, that will go a very long way for us.

Mike

[mlewis_apc]

Just had another, um, I'd call it creative thought.

As the RT machine is taking over, I'm going to have four Smart-UPS 3000's sitting idle.

Since they output 120VAC at the outlet, perhaps they would be a safer bet for absorbing a sudden jump between 208VAC and 240VAC? The current setup has two step-down units connected to the RT. I could just connect the 3000's which are 120VAC input, into the step-downs if that's possible. Not sure you can run a UPS off of a UPS.

You mentioned that there would be a spike in voltage to the load but you've not once said that the step-down could be damaged so if it could handle that, would the above idea work? In fact, I would not even need batteries in the 3000's since they are being fed by the RT.

And if this were an option, what am I looking at for a loss in terms of power, to run these off of the main UPS,E

[mlewis_apc]

Does APC make any step down transformers to go from 240VAC to 208VAC? It seems that this would be the simplest way to fix this mess I've got.

[mlewis_apc]

Thanks for your input!

I understand that you aren't guaranteeing any information in this thread and understand that. Just trying to get all of the information I can to make proper decisions, based on what I can do (budget).

I'm trying to get a handle on just how nasty this setup might be. It has not been clear to me just how much of a jolt going from 208 to 240 might be if the ups goes into bypass. Based on your post, it gives me a sense that if this happens, it might not be as catastrophic as I may have thought.

Perhaps I'm ok with this setup for now then but have also posted asking about possibly putting another step down in the mix, from utility to the ups. This, it would seem, would take care of the problem of any spiking voltages.

I've not found any device so far which does 240vac to 208vac however.

Mike