Published 7 Sept 2012

A few words on the Powerware PW5115 UPS

One of these Powerware uninterruptible power supplies was purchased for the office during 2012. This is a brief overview and a few notes on the operation to date.

panel pic This is the tower version of the 1000VA model. The unit is 340mm long, 150mm wide and 200mm high incl the rubber feet. It weighs 12.8Kg. There are three AC outlets in this model. Control and monitoring is via either RS232 or USB to a host pc running the provided 'LANSafe' application. I couldn't decide why Powerware called the application Lansafe, because it isn't that easy to remember and does not jog one's memory by association. Although the unit has ethernet ports in and out, there is no provision for monitoring status via the home network unless you buy the optional network card. The RJ45's do provide transient protection however. There is no provision for connecting external batteries; if one was devise a DIY solution, bear in mind this is a 24Vdc model.

Accessories in the box

Assembled in China
C tick N869

Warranty nominal 2 years but registration may increase this.

Monitoring screens

The basic three views are 'PowerScope', 'Control Room' and History Data

Powerscope screenshot
My incoming mains is 244V, path is 'straight-through', the charging system is 'resting', my load is 25% and the battery runtime with this load would be 28 minutes.

Control room screenshot
The control room screen expands the data a little and includes AC frequency. My load is 190VA which isnt quite consistent with being 25% of the 1000VA rating of this model.

History page

Input/Output switching

This Powerware model is 'line-interactive', which means the unit has a mains buck and boost transformer to maintain the output AC over a more narrow range than would be the applied AC. This method does prevent the unit cycling onto battery power unless the mains does get very low. It is debateable whether there is any real advantage to the load-side equipment in having this buck/boost provision because most IT equipment these days has wide range switching supplies anyway.

I did plot the input/output characteristic and the result is the graphic below:

In-Out plot
Red line is mains input and the dotted blue line is what happens at the output and with the different modes highlighted. The plot looks a bit jaggy because I only plotted 5 volt steps. The unit switches to battery below 205V input. As you can see for an input range of 205V to 275V the output AC voltage is kept between 224V and 248V by using buck/boost techniques. There is a short transient break when the unit switches to and from any mode. An incandescent lamp on the output gave a brief flicker each time, however, the pc or the router did not care.

Charge modes and inverter waveform

When I first powered up the box, it went into charge mode, then after a few hours switched to float. It stayed in float mode for over 2 days. On float, with no load, by the end of 2 days, the UPS was drawing 16 watts of power with PF=0.61. When float charge is finished, the unit goes to 'resting' mode. I didn't record power consumption of the unit when resting, but it will be less than 16 watts, since the fan turns off.

float charge
Yellow line is the AC mains waveform incoming at the office. Green is the current waveform presented by the UPS during 'float'.

Next I plugged in a 75 watt incandescent lamp and failed the mains. The following pic shows the waveform of the inverter.

On battery
Yellow line is the inverter voltage waveform Green is the current waveform from the 75W lamp. Voltage distortion is 5.1% and frequency is exactly 50Hz.

Concluding remarks

When the mains fails, and the pc is running, the powerware application does wake up and will shut the pc down in a time that you can preset. You tell it how long your pc normally takes to shut down, and how long you want to delay the process for. It works fine. To date; over 4 months, the PW5115 is running normally and without fault.

Axino-Tech Consulting & Services , September 2012.

From: Axino: March 2017

New batteries and a fault

It was back in mid-2016 when the 'replace battery' warning was first seen. I didn't action that immediately. In February 2017, the UPS fan began running at maximum full time and on inspection, the entire unit was very hot. It would not run a load on battery for more than a few seconds and neither could I communicate by USB as it had been since installation. I took the batteries out and they were almost too hot to touch.

On enquiries to the local agency, it appears that failed batteries do cause the unit to become hot, so they had to be replaced. The 2 x 12V batteries were actually not that expensive and they arrived promptly. Re-installing them was simple and the UPS came back to life. It charged the batteries for a couple of days with the fan at low power, then, as designed, the fan stopped and the unit looked to be running normally. However it still would not communicate by USB. The software loaded on my Windows pc simply said 'no UPS found'. I enquired again and was told that Eaton neither supply parts for these "smaller" UPS models nor will they provide a schematic. This seems to me to be protectionism of the highest order - it is only a UPS, not a guided missile component! In fact, by that policy, Eaton is effectively saying, if it fails, just buy a new one. To me that attitude is poor and would make me think again about using the brand. I will take it on myself to look at the USB board at some stage, there might be an obvious failure and a commonly available part.

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