The Curious Case of the UPS Loading

We recently got to review input and output monitoring data from a UPS system (make and model not specified) feeding a medical imaging system. The monitoring was done as a precaution, but we noticed something unusual.

First, take a look at the RMS voltage and current logging of the UPS input and output. Phase A voltage, Phase B current shown for clarity, but all voltage and current phases are balanced and similar.

UPS Compare Input RMS

UPS Input – Normal facility RMS voltage (daily fluctuations, with occasional sags) and RMS current peaks at approximately 80 Amps.

UPS Compare Output RMS

UPS Output – Highly regulated RMS voltage (with small load related fluctuations) and RMS current peaks at approximately 170 Amps.

The discrepancy between the input current and output current is unusual. It would be typical for input current to be marginally higher than output current (due to device efficiencies) but not lower. Our guess – the UPS DC bus (and probably, the battery string) is being called on to support the peak output load.

UPS Compare Output Highest Load

UPS Output – Step change in load current and nonlinear load is typical of medical imaging system. Very small fluctuation in output voltage related to load changes, and small increase in voltage distortion related to nonlinear load current.

UPS Compare Input Highest Load

UPS Input – Even at highest levels, current is linear, UPS must have a unity power factor front end / rectifier. However, lower current level is unusual, and indicates that UPS battery is probably being called on to supply the peak medical imaging load.

There’s really no immediate problem here – the UPS is doing a great job of correcting input power issues, as well as supplying the complex loads (step change, pulsing currents, nonlinear power factor) of the medical imaging system.

However,it’s pretty clear that the UPS batteries are getting discharged during highest current imaging system operations – not really their intended purpose, which is to ride through far less frequent utility sags and outages. So it’s possible that the UPS batteries are being stressed and may degrade or fail prematurely, and need replacement. We’ve referred this to the UPS manufacturer / supplier for attention.

As a quick “in the field” test (we’re doing this analysis remotely, not on site) we might suggest disconnecting the battery string temporarily, and seeing how the UPS performs without the battery, just relying on the DC bus. We’re guessing the UPS might start to collapse or struggle to supply the medical imaging load – and may be undersized for the application without the battery string supplied.

We’ve seen situations where a UPS that has heretofore worked well for years stops working quite so well, because the batteries started to wear out, and the unit was no longer able to supply the peak loads required by the imaging system.

The Guru’s Cat

When the guru sat down to worship each evening, the ashram cat would get in the way and distract the worshipers. So he ordered that the cat be tied during evening worship.

After the guru died the cat continued to be tied during evening worship. And when the cat died, another cat was brought to the ashram so that it could be duly tied during evening worship.

Centuries later learned treatises were written by the guru’s disciples on the religious and liturgical significance of tying up a cat while worship is performed.

– Anthony De Mello, The Song of the Bird

A music festival where I’ve been a volunteer for nearly 25 years is doing their annual mid-winter pre-fest sales – selling a limited number of tickets at a reduced price. It’s a good way to carry the festival organizers over the winter, and to give regular festies a price break.

What’s NOT so good is how they do it – phone only, with a limited staff processing orders manually over a three day period. I’ve seen some posts on social media:

“After 111 attempts to get through, over a span of twelve minutes, tickets have been procured!”

Mine took longer than usual — 179 calls and 48 minutes (you re-dial faster than I do) . . .

and from one of the folks on the other end of the line:

FYI y’all S & A are working fingers off to accommodate youralls calls for tix & are very grateful for your wonderful patience

See, the thing is, this could be done online through eCommerce – put a limited number of tickets for sale (so you do not oversell) and for a limited time. Yeah, there’s a service fee (but probably not all that much higher than the credit card fees) and I suspect most customers would pony up an additional $5 or $10 per ticket to cover an eCommerce solution (and not have to dial in 100+ time). You could sell out your winter pre-fest stock without having to tie up customers, your staff, etc.

But….it’s been done this way for 25+ years and will probably always be done this way. Like the Guru’s Cat, sometimes we do things out of habit or tradition or inertia without stepping back and considering other options.

Calculating Voltage Imbalance

Working on a customer site with Fluke 1750 data at the moment. The customer notes “Error shows udc voltage out of tolerance between stationary and rotating portions of the gantry.” – problems with the main DC bus voltage. Made me think it might be voltage imbalance, causing high DC bus ripple.

Voltage Imbalance Chart 1

Looking at the Fluke 1750 voltage imbalance chart shows a maximum imbalance of 1.1344%.

Voltage Imbalance Chart 2

Looking at the individual RMS voltage measurements, the RMS values are Ph A = 281.34, Ph B = 281.715 and Ph C = 276.725. Voltage imbalance seemed a little high to me; so I decided to double check the Fluke 1750 voltage imbalance.

There’s a good article on calculating voltage imbalance on the ACHRNews (Air Conditioning / Heating / Refrigeration News) Website, here – Three-Phase Motor Voltage Unbalance – specifically, calculate the average of the three phases, take the maximum deviation from average (of the three phases), and divide by the average.

In this case, the average voltage is 279.927 Vrms, and the maximum deviation is Phase C, 279.927 – 276.725 = 3.202 Vrms, Voltage Imbalance = 3.202 / 279.927 = 1.144%.

Close enough. The customer requirement is 2%, so while this imbalance looks a bit large (nearly 5 Vrms between Phase C and the other phases), it seems to meet the requirements.

Philips Power Solutions

I was the national Power Quality Engineer at Philips’ North American HQ circa 1989-1995 and laid the groundwork for a lot of this. So this is interesting to see.

Overall, pretty well done. The “lousy power” waveforms are a little unrealistic / conceptual (I’d have insisted it was a little more realistic) but they hit all the high points. Think they futzed up the isolation transformer based UPS technology a bit (the isolation transformer is unique, but does not provide the conversion from AC-DC which is pretty standard in all online UPS systems). Interesting to see Rx Monitoring Services reports spotlighted; a good partner choice if one is using power protection as a revenue source.

I never got a kick ass video for my power program, if I recall correctly…


Good Deed of the Day

Social media good deed of the day – a local contractor (with all of 140 Facebook fans) has been dutifully posting project updates of work done for one of my social media clients (with 26,000 Facebook fans) and tagging us. I noticed.

This morning I did them a solid – grabbed a few photos of the work in process / completed, gave them a shout out and a link, and posted it to my client’s timeline, where, unboosted or sponsored, it has been seen by 1400 folks so far – 10x their organic reach. Great social media fodder for us (infrastructure improvements as we move into the fall / xmas season) and super great exposure for them.


Use social media folks, it works!

Social Media: Bad Timing and/or Tone Deaf


Popped upon my social media feed this afternoon.

Price Chopper is running a sponsored ad touting their support of Riverfest, at the same time the cancellation of said event is all over most social media feeds.

Riverfront Cancel Facebook

It’s one of the reasons I’m a bit hesitant to embrace scheduled, planned social media posts, and have a more hands-on, direct approach. Because one never knows – some sort of political incident, tragic accident, hilarious meme, or other news story could crop up and the juxtaposition of a social media post (sponsored or otherwise) with a problematic news story could result in a social media fail. Even if there’s no direct connection (as there is here), promoting a fun and games event in the wake of a crime, attack, or natural disaster is at best, tone deaf.

I do schedule some things, but I do so judiciously, and keep an eye on things – ready to pull the plug at any time. And I notice what companies and organizations seem to be managing their social media somewhat robotically or blindly – and make some assumptions about the entity’s customer service accordingly.

God Takes Care of Fools and Small Children

Recently, I’ve noticed a Sponsored Post coming across my social media feed.

Berkshire Sponsored Post

The State of CT Tourism groups is promoting it’s new CT Visit website (and tourism in general) with a post theme – Sea / Air / Risk / Reward. And right in the middle of it is my good friend Robert Zirpolo and his hot air balloon company, Berkshire Balloons.

Now, Robert is way behind the curve on internet marketing. I set up a website for him years ago, and migrated it to a free blog type page so he could update it himself. I’ve set up a Facebook account, and post to it occasionally, but if he posts to it more than a few times a year (usually a “happening now” post of passengers posed pre-flight) it’s a lot. Sponsored or paid advertising? Not hardly. Robert is no fool, but he’s not very aggressive nor savvy when it comes to social media marketing.

And yet, here he is, beneficiary of an aggressive (and no doubt, costly) state of CT tourism campaign. Robert commented this week as he called up looking for crewing help “for some reason, everybody wants to go flying this week”. Pretty sure I know why….

It’s not completely happenstance – Robert donated time, propane, and equipment for a couple of State of CT film shoots last year – I was along to crew for both dates (a windy “no inflate” shoot at Lyman Orchards, and a short, flight with camera, video, and drone filming out of Meriden’s Hubbard Park)

But still – you can’t buy this sort of exposure. Or perhaps, you can’t AFFORD this sort of exposure.

Spreadsheet Automation

We’ve spent some time recently putting together a spreadsheet for a client to review advance reservations for a local Dinner Train. It is intended to help management and marketing look down the road to fine-tune marketing and social media efforts.

The magic is the use of templates and macros – the spreadsheet is designed to quickly and easily import data obtained from an eCommerce platform (Shopify), and with the push of a button, to sort, filter, and copy the data so that the charts are automatically produced – in less than a minute, and by users who are not spreadsheet gurus.

Dinner Train Instructions

Step-by-step instructions embedded into the spreadsheet to ensure non-expert users and/or new users can work with the spreadsheet.

We set the spreadsheet and graphs up just once – and through macros, paste new data into the spreadsheet, so that the graphs are updated and ready for use without touching them at all.

DT Spring 10May16B

DT Spring 10May16C

DT Spring 10May16D

Just one of our many skills and services – if you have data that you’re having trouble making good use of, or are spending too much time on repetitive tasks to get your data into useful form, give us a shout. A few hours of work setting up an automated spreadsheet can yield huge savings down the road.

Meet the new boss…..

Siemens Healthcare Becomes Siemens Healthineers

We’ve been working with Siemens since 2001. Somewhere along May 2009, we transitioned reports and templates from being branded as Siemens Medical Solutions to Siemens Healthcare. So I suppose it’s about time for a bit of rebranding. Pretty minor change for us (the word “Healthcare” appears a grand total of 2x in the report templates we start from.

The new name embodies the company’s pioneering spirit and engineering expertise in the healthcare industry. It is unique and bold and gives a new identity to the organization and to the people – the people accompanying, serving and inspiring healthcare providers worldwide – the people behind outstanding products and solutions.

Makes me think of Walt Disney and the Imagineers (I’ve recently watched a PBS biography of Uncle Walt).

Day Out with Thomas 2016

I’ve spent a few hours each of the past three weekends riding herd on social media and eCommerce for my clients down in Essex as they have hosted Thomas the Tank Engine.

Kind of remarkable how Instagram has become the go-to social media platform – we had our fair share of check-ins on Facebook and a few posts – but scores of Instagram photos – wonderfully annotated, tagged, liked, and commented.

Instagram Sunday 1May16C

Trigger warning for cuteness, face-painting, kids in firetrucks, looking giddily terrified on the gentlest of carnival rides, and of course, Thomas, Percy, and Sir Topham Hatt –