Help reading power usage on powerware UPS

[sephlaire]

I have a powerware 9330 (30KVA unit.) I'm attempting to read the meters on the device to determine how much power is still available to be used but I'm not sure if I understand everything right.

Below are pictures I took of the meter readout and I was hoping someone could take a look and help me out.

http://www.mediafire.com/?1zt6nlf6ay1859u

http://www.mediafire.com/?c8k65makgwwi6m5

http://www.mediafire.com/?x3a5l5makd0i39a

http://www.mediafire.com/?g7q4hjbawskctw7

http://www.mediafire.com/?49ap9kwdtgka5xd

From my extremely limited understanding of KVA/KW/PF I think I am within the UPS's limits but I'm not 100% sure. Any information is greatly appreciated.

-Josh

 

[FredWagner]

That's quite a unit!. You're well within limits a bit under 60% load with 40 minutes runtime. As you add more load, the runtime will decrease proportionately, but with something this sophisticated, you probably have the option to add more battery capacity if needed.

Fred Wagner

 

[sephlaire]

Thanks. My main concern with reading the meter is that on the input screen, it shows 17.6 KVA. Does this mean that I am only getting 17.6 KVA input from the power supplied to the unit?

Because that would mean to me that even though the unit can handle much more power, my output KVA is only 0.6 lower than the input... In my mind this means that I cant add anything else without using more power than is supplied by the power company. Is this true based on the images I linked above?

 

[JimInKS]

That just shows the power being consumed by the unit so you are in good shape. This Input power consumption will always be slightly higher than to output power due to conversion losses.

It is consuming 17.6KVA and you are getting 17.0 KVA usable power out. 17 / 17.6 = 96.6 % efficiency. Not bad.

The wasted power is used to run the electronics of the unit and trickle charge the batteries.

 

[FredWagner]

Any unit will have a slight inefficiency. Your equipment is drawing what it does, and the UPS needs a bit more to run itself, keep the batteries charged, etc.

Your output power is 17.0 , your input load is 17.6 - about 96.5% efficiency. If you up your actual load to 25KVA, the draw from the power company will likely be around 25.9KVA - still a 3.5% overhead. Another thing to keep in mind - the switching power supplies in all of our equipment are designed to provide a constant voltage output, so if input voltage sags, they pull more current.

Some UPS units provide a boost function (like a line conditioner), others just cut over to battery power when input falls below a certain point. Suggest you study the documentation or manufacturer's web site to learn more about your particular unit. It sounds like you've got lots of reserve capacity.

Make sure your batteries are tested and inspected regularly. You probably have a service contract for that. And they'll need to be replaced periodically - learn what that interval is, and budget for it.

Also, plan for extended power outages. Will you gracefully shut down before your batteries run out, or do you have a Diesel Generator that can carry the load, with the UPS only taking care of things until the Generator cuts in ?

Fred Wagner

 

[sephlaire]

Thanks! all of these answers are just what I needed to know.

Fred, we do have a generator that kicks on when the power is out that will supply the UPS.

Thank you all again for your great help.

 

[jknichols]

Make sure your batteries are tested and inspected regularly. You probably have a service contract for that. And they'll need to be replaced periodically - learn what that interval is, and budget for it.

Budget? What's a budget? Around here we wait for the battery light to start beeping, then go thru 3 weeks of bidding / procurement to get them replaced! LOL! (Well, not so LOL, I'm half serious)