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]

Got the second step-down working so things are set up now. Everything which should be on the unit is running minus some storage hardware.

Internal Temperature: 87.4°F
Runtime Remaining: 20 minutes

Power
Input Voltage: 243.3 VAC
Bypass Input Voltage:
Output Voltage: 207.0 VAC
Current:
Input Frequency: 59.99 Hz

Load
Load Power: 44.0 %Watts
Apparent Load Power: 39.0 %VA
Load Current: 17.95 Amps

Battery
Capacity: 100.0 %
Battery Voltage: 216.0 VDC
External Batteries: 1

So, with my geny which puts out 50AMPs, what load percentage do you feel I should be safe at, where it should not cause the UPS to go nuts in any way? It was mentioned that if the UPS was not able to keep the load up, that it would perhaps switch back and forth between utility and geny.

Mike

[BillP]

1.) APC doesnt have any stepdowns that do 208v->240v 😞

2.) here is what we have on [generator sizing|http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=7300]. this would apply to your UPS as well since its very similar to a symmetra.

[mlewis_apc]

Ah, someone was telling me that your SURT003 would do that job.

I'm not sure how to use the geny information.

From what I'm reading, it's 1.5 times the capacity of the unit but if I'm not using the unit at max, then this could mean AMPS being used right?
So, I need one and a half times what I'm using on the UPS. So, if I'm using 20AMPs on the UPS, this means I need 30AMPS from the geny?

[BillP]

oh i kind of forgot about that! i wouldn't really buy one just for that feature but i believe you are right. i apologize! SURT003 has one L6-30R that will output 208v with an input of 240v (or an input of 208v as well). this is the only outlet that will output 208v by the way.

and yes i think you are right about the generator, as long as your load is static.

[mlewis_apc]

Good, I'll give it a try on the geny next weekend perhaps and see what happens. My fear is something which was said, that if the UPS can't sync or keep up, that it might switch back and forth between bypass and not.
That's pretty much the only reason I was wondering about a step down in front of the UPS, to make sure this would not happen.

[BillP]

a double online conversion UPS can accept such a wide range of voltage and frequency and crappy power so if you see it switching back and forth, then something is really wrong with your generator power and you should probably get it checked out since this type of UPS can handle a good amount of crappy power and not care.

[mlewis_apc]

Finally got this tested tonight and all went well.

I was very surprises however when I saw that the geny output is 220VAC and not 240VAC. This I know I adjusted to 240VAC last year so there's a loss somewhere along the path.

When the UPS kicked in, before the transfer switch gave it geny power, it first said I had some 20 minutes of power on batteries but started going down much faster. Is this indicative of the batteries not being as fresh as they could be?

So basically, the UPS went from getting 240VAC, to nothing, to getting 220VAC. It took a few moments to sync up or what ever it does and went back to normal mode, on geny power. At first, we didn't think it would work because it kept switching between it's batteries and the geny but maybe one minute into it, it took.

I kept it running for about 15 minutes and all was fine, the UPS never once blinked.

Last Battery Transfer: Detection of a line voltage notch or spike
Internal Temperature: 87.4°F
Runtime Remaining: 7 minutes

Power
Input Voltage: 220.3 VAC
Bypass Input Voltage:
Output Voltage: 209.4 VAC
Current:
Input Frequency: 58.29 Hz

Load
Load Power: 56.0 %Watts
Apparent Load Power: 45.0 %VA
Load Current: 21.46 Amps

Battery
Capacity: 51.0 %
Battery Voltage: 216.0 VDC

[mlewis_apc]

how much actual runtime did you get? i imagine you arent sure since the generator kicked
in and it never discharged completely.

When I started the test, it was at 20 minutes, within about 120 seconds or so, it went down to 7 minutes. During that time, once the xfer switch sent geny juice to the UPS, the UPS seemed to switch back and forth between batteries and the geny, trying to sync up I am guessing.

I didn't have the nerve to run the batteries to the limit because I didn't want to take the servers down accidentally.

Very nice to see it all come together though. I'll have to try another test and load up the UPS once it's on geny to see what I can get away with.
What signs should I be looking for that the UPS is about to give up when doing this? If I recall, someone mentioned that it might try to go into bypass mode, which would be bad.

Mike

[BillP]

the runtime reported by the UPS while its online is an estimate. as it operates on battery, it becomes accurate.

how much actual runtime did you get? i imagine you arent sure since the generator kicked in and it never discharged completely.

[BillP]

do you mean what signs the UPS will show when its low on battery? or when it wont sync to the generator?

[BillP]

great to hear. that is what i am here for 🙂

[mlewis_apc]

do you mean what signs the UPS will show when its low on battery? or when it wont sync
to the generator?

The system should tell me when the batteries are getting low but yes, I mean when I'm about to go beyond what the geny can provide to the UPS. As I recall, if the UPS is not getting enough power from the geny, it'll start switching between batteries and geny, right?

[BillP]

yeah, you're right - it will go to battery if it does not like the power (voltage, frequency) from the generator. the only thing you would see though is a notification of a power failure or input power problem though if this were to happen but if you knew it was running on generator, you would put two and two together i imagine that it was caused by the UPS not liking the generator power.

[mlewis_apc · Accepted solution]

it will go to battery if it does not like the power (voltage, frequency) from the generator.
the only thing you would see though is a notification of a power failure or input power problem

Ok, so it's looking like we're good. I'd love to find a large step-down to put in front of the UPS to make sure the load never gets that 240 spike (or 137VAC I think you calculated it at) but other than that, looks like it's all good.
And if I notice that the UPS can't sync up with the generator, it'll most likely mean I need to shut some things down to keep it within range that it can stay up using the geny.

Wow, can't thank you enough for sticking with me on this. It was a long thread but it certainly has helped to get us up, running and safe. I guarantee that this means we'll keep on using APC as things get better with our business.

Mike