2.02.2008

Power Quality 2008

I'll be heading out to Las Vegas at the end of the month for the Power Quality Conference, held concurrently this year with the Electric West show.

On Thursday, Feb 28th I'll be chairing PQT 6: Energy. Oh goodie - I'm such a fan of companies that promote "Energy Savings Through Power Quality". I'm all for energy savings and all for power quality, but I am dubious about companies and products that promise both. Smoke and mirrors, often.

On Friday, Feb 29th, I'll be presenting a paper in session PQT 9 - Case Studies – Medical entitled "Power Quality in the Mobile Medical Environment". Once again, it will be me, and two presenters from GE Healthcare. Also, someone from EPRI (last conference, it was me and three GE Healthcare papers).

If you are headed to the conference, do look me up, and say hello!

8.16.2007

The Road to Perdition.....

....is paved with good intentions. And the road to poor power quality is paved with power conditioning devices. Four examples:

1) Reviewing a power quality study, wherein the complaint is a chiller that is shutting down due to excessive voltage imbalance. The voltage imbalance chart showed unusual step changes in voltage balance, often exceeding 2%. The problem: the site had a tap-switch voltage regulator installed, and as individual phases were regulated, voltage balance jumped from relatively balanced to relatively imbalanced. The solution: Bypass the voltage regulator.

2) A second study, with imaging artifacts affecting an MRI system after several years of satisfactory service. The system is protected by a UPS, and shows a higher than typical number of load related events. The problem: the UPS requires the battery string to supply the maximum imaging system load. As the batteries have aged, they were unable to support the peak load. The solution: service the UPS / battery string; in all likelihood the battery string needs to be replaced. A different UPS, that did not rely on the battery supply peak power, would not have had this problem.

3) Finally, a site with repetitive (~ 10 minutes) and severe low frequency transients. A facility based capacitor bank, intended to correct voltage and power factor, is malfunctioning - the capacitors pull in, and then shut down 45 seconds later (for so far unknown reasons) - probably internal fault or error indications. Ten minutes later, the caps try again. A CT scanner has been damaged repeatedly by this problem.

4.03.2007

Patent (Not) Pending

I periodically Google PowerLines, just in case. Today, I found a patent that was recently assigned:

United States Patent 7164275
AC power line impedance monitoring method and system
US Patent Issued on January 16, 2007

Two devices that I had a hand in were referenced in the patent. The novel bits seem to relate to a capacitive resonant circuit used to assess the inductive component of the impedance. We are impressed!

Invented by Mike Gaspari, assigned to Rockwell Automation Technologies, Inc. I wonder if they will be coming after me (too late, we stopped selling the ZM-100 a few years back). I'm going to try to contact Mr. Gaspari - because it looks like a neat device and I hope it gets turned into a measurement device.

11.15.2006

RSNA 2006

I'll be working with TEAL Electronics at the 2006 RSNA Meeting / Exhibits, to be held the week of Nov 26th in Chicago.

Coming to the show? Stop by the South Building - Hall A - Booth 1815 and say hello. I will be there Sunday through Tuesday.

10.17.2006

Been a While

Life gets busy, eh? Apologies for not blogging here of late. A few updates....

The good folks at Dranetz-BMI stopped by; I went to a seminar in Springfield, and liked what I saw, and they brought down the PX-5 power analyzer. FINALLY something from them that I think we can work with. I've always been a BMI kind of power quality person, never liked Dranetz (from the 626 backwards text printing, to the penchant for the 656 and 4300 to fill up memory) but I think in the PX-5, they have finally melded the BMI and Dranetz technologies (giving you options with each philosophy), the memory technology has become cost effective, and the GUI / operating system seems flexible and powerful (as opposed to powerful and cumbersome). I'm strongly recommending these to some clients and look forward to developing reports and analysis tools for them.

Magnetic fields are back on my mind - an upcoming site visit to a clinic on Long Island, and some inquiries for a magnetic field training program. I recently picked up a DC gaussmeter, and I am thinking of putting together a small book or manual on B-field hunting.....

Finally, you can catch me live at the upcoming Power Quality Conference in Long Beach, CA - I'll be presenting my paper "Optimizing Mains Impedance: Real World Examples" on Thursday morning (October 26th), then chairing a workshop on Wiring and Grounding. And I'll be working with TEAL Electronics at the upcoming RSNA meeting in Chicago - look for us in the South Building - Hall A, Booth 1815. Nothing like late November in Chicago to get you in the holiday spirit, put the chill of winter into your bones, and get your corns and bunions aching!

8.17.2006

Looking for a Job?

For whatever reason, I've been getting a bunch of phone calls from people looking for a job. I think my internet and industry footprint is large enough that people find me pretty quickly via search engines - and are surprised that its for the most part, just me. In any case....here's a couple of resources for those on the hunt

Lineal Recruiting Services (Trumbull, CT) - www.lineal.com - I've never actually met Lisa Lineal but I've seen her ads in Power Electronics, Power Quality, EC&M, etc. ever since I've been working (1983). Scary huh?

Power Technology Associates (Sharon, MA) - www.powercareers.com - I think I've spoken to these folks on occasion, and have probably met some of them at various shows and conferences.

Hope these help - good luck on your job search!

7.18.2006

Vacation: Wed July 19 - Fri July 21

Jude will be on vacation on Wed - Fri, July 19-21. She'll be offline during this period, but will have cell phone access if you need to chat. Back in the office on Monday, July 24. Stay cool!

7.12.2006

Medical Imaging Magazine

This one is a bit dated (Feb 2006) but I guess I was intereviewed.

6.28.2006

Harmonic Panic

Just looked over some power quality studies and an associated string of emails. The expert commented that the high harmonics on the neutral (49% and 51%, two panels) were a major problem, and required "doubling the neutral".

Of course, the fact that the actual neutral currents averaged 10-15 amps, and never exceeded 250 Amps maximum (on a service entrance panel rated for, oh, 800 Amps) apparently got by this expert. And the voltage harmonics, 2% maximum on one panel, 3% on the other, were a little elevated, but not in any way problematic.

This, my friends is why I treat every diagnosis of high harmonics as suspect unless I see the data and run the numbers. Because too many people know how to hook up meters, push the "automatic report" button, and jump to conclusions. And not enough people have a clue what it all means.

5.22.2006

How Good Is Your Ground?

An article in EE-Evaluation Engineering, as passed along by a client. The article is by Vladimir Kraz, Credence Technologies, and J. E. Patrick Gagnon, Texas Instruments. Good piece.

My comment: the article is written from the perppective of a controlled environment (i.e. - semiconductor test, wafer fab, etc) where there is a lot of thought and investment in a good, controlled, ground plane / grid / system - and the goal is to get connected to this ground plane as solidly as possible. For a lot of the systems that I work with (i.e. - medical imaging) there is no deliberately conceived ground system - so things are a lot murkier. If one is trying to break up problematic ground loops / paths, the last thing one might consider is improving the system coupling to the outside world....

5.18.2006

Oh, Just Use the Ground

I'm back from a site visit; an MRI system has been having issues. On site, I discovered that a large UPS, which apparently requires 5 wires (3 phase, neutral, and ground) has been connected with a short jumper or bond between the neutral and ground - since a neutral was not run to the device. This was with the sanction (in fact, at the direction of, via the installation manual) of the manufacturer (not a small or fly-by-night vendor, I might add).

The result: 8 Amps of current (presumably from the input rectifier filters) on the protective ground conductor. At another site, we measured 16 Amps of current on the neutral-ground bond (not all of which flowed to the source on the ground conductor, mechanical mounting and conduit connections presumably taking some of the current)

OK, folks, it's Power Quality 101. YOU DON'T USE THE GROUND TO CARRY CURRENT.

I guess it shocks me (heh-heh, thats a pun) that in 2006 people are still doing the same sort of things that got the whole power quality mess started in the old days.

I got to drag out my leakage current and ground current meters and put into practice some of the things I wrote about in my last Power Quality paper: Leakage and Ground Currents: Measurement Techniques

4.27.2006

Keeping It Clean

I direct your attention to this article, in the May 2006 Issue of Evaluation Engineering.

Robert Close, who works for my client TEAL Electronics Corporation, put together a nice article. But the three waveform graphics embedded therein are whats really important. Those are screenshots from the TEALwatch Viewer - an Excel based data vieweer that I put together for the new TEALwatch power monitor.

Nice to see your stuff in the media....

3.20.2006

Online Coupons

Just something I've put together that's kind of interesting. I've developed an online coupon for one of my clients.

Some interesting features. The border, graphics and body text are all images, so that they print out properly regardless of browser, printer, or screen resolution. The coupon pulls a date, time, and coupon number from the host via CGI scripts - which reduces the odds of mass reproduction. The bar code is kind of a ruse - it simply says ESSEX STEAM TRAIN but it does add an aura of officialness. And the "valid dates" and the authentification field (below the bar code) can be modified by the client using Blogger technology.

Pretty spiffy....if I do say so myself!

3.17.2006

UPS and Emergency Power

Cross-posted from a Bio-Med list. I took the time to write this so why not share with my fans and clients?

We've had a couple instances of losing E-power (switching to generator) and many of our UPS units failing to provide any backup. These power losses are for just seconds. Today we had a stack of new APC 750's that not only failed to back up but when power was restored it still would not power the computer plugged into it! Has anyone else had this type of experience or know what might be causing it? Does anyone have a recommendation for a rock solid UPS or a way to keep them from getting knocked out?

I'm not a huge fan of stand-by (or line interactive, which are mostly the same thing) UPS's for emergency power system use. I suspect that's what you have here.

Most of the time, such UPS's feed regular power to the load. When an outage is sensed, the inverter switches in and feeds the load. There is some dead time (usually in the 8 - 16 msec range, 1/2 to 1 cycle). This works pretty well for normal power - the utility rarely fails abruptly (typically some drop in voltage over several cycles, as motor loads backfeed the line) and the UPS transfers over cleanly with a minimal impact on the load.

Emergency power systems provide a lot of complications. Most of the time, facilities persons fire up the generator, bring it up to speed / sync, then exercise the transfers switches to "test" emergency power (which is not the most realistic test of the emergency power system, but has minimal impact on the facility). As a result, there is often a short transfer time (from 10 - 50 msec) and based on my power monitoring over the years, that transfer time is abrupt and often has high voltage transients that are going to get past the UPS (not yet switched to inverter) and the TVSS (designed for high voltage, high frequency transients, not relatively low voltage sub cycle transients)

In addition to the unusual outage profile, emergency power can bring to the dance frequency fluctuations, voltage distortion, and out of phase transfers that some UPS have problems with. Again, not what the utility normally does, so perhaps the highly engineered to take cost out UPS's are not designed to deal with.

If you have access to a power monitor, I might suggest monitoring (a) a normal emergency power test (no UPS) and (b) the output of your UPS. I suspect you will walk away kind of amazed that you are not having more issues.

My advice: for critical system on emergency power, use an online UPS (not stand-by or line interactive) - these will provide no-break power. Yeah, they will cost more. There are a lot of vendors out there who do that sort of thing, and I don't have a particular favorite - the key is to look for online, double-conversion technology. APC has some of these although maybe not in a small (750 VA) size that we are discussing.

You also might consider that the UPS you are using in undersized. Your load might power up fine while on utility, but the inverter might be collapsing due to load inrush. So the load will not power up when the UPS is on battery. If you mean "generator power" being restored, its possible that the UPS does not think the generator power is good enough (frequency, voltage level, voltage stability, waveform) and so is still running from battery / inverter. I would take a known good UPS and try to power up the load with the line cord unplugged - I suspect the issue is that the UPS is undersized to supply the inrush current while on inverter.

I'm not APC or standby / line-interactive bashing here - that's what I use in my office for my server / desktop. The price is right, they make a ton of them so reliability is good, they work well for normal computer loads and normal power, and the software interface to my network is good. But in my experience, emergency power systems cause problems for them often enough that I would not consider myself "protected" unless I had been through a few months of emergency power testing without an issue, and had a good idea what the emergency power system testing looked like (power monitor) on the line side as well as the load side of the UPS.

2.27.2006

Sending Large File

We've recently put together some instructions for uploading large files that might not get through the email system. Find the FTP Instruction in PDF format here.

Eventually, I'll put together a web interface for this. One thing at a time....

2.04.2006

Move Complete

We've been busy this week moving PowerLines into a new office in the Newington Office and Conference Center. Thanks for the patience with phone / fax / email if you had some issues - tried to make it seamless and maybe succeeded.

We've moved to the front of the building, with big windows; smaller but ncier than the old office and a big step up from the spare room at the house.

With the move of a few larger pieced of furniture this week, the move is complete. Lots of filing and sorting and organizing that can be done as time permits.

1.25.2006

PowerPoint Tips

Can be found here.

Appropo of nothing, just found them recently in doing a web search and they were well written and useful.

1.20.2006

Of AVI's and CODEC's

I'm playing with some screen capture software that grabs a desktop or window over time into an AVI file. From thence - most likely I will be importing things into PowerPoint. As such I am learning about CODEC's which seem as inscrutable as anything I have encountered.

The CODEC provided with the capture software compresses the animations (15-30 second sequences) into smallish (200-500K) AVI files, some of the other CODEC options are much, much larger. I would hope to find something to use that is more or less standard / generic (i.e. - portable).

Looks like I have some research and perhaps experimentation ahead of me. Pretty useful capability to have for presentations, training, websites, tutorials, etc.

12.30.2005

2005 Wrap-up

Guess its that time again....

2005 was a good year for PowerLines. We reviewed data (power quality, environmental, or both) for 402 sites for one of the medical imaging OEMS. We connected with a handful of new OEM clients and continued to work with many more. Jude spent the summer working with the Connecticut Sun (WNBA) which does not have a lot to do with power quality, but was enjoyable nonetheless! And she visited a lot of states, put together a number of training programs, and in general, kept moving forward in power quality!

Thanks to all of my peers, clients, friends, customers, and collegues. December of 2005 marked 10 years in business as PowerLines. Hard to imagine....here's to the next decade!

Safe and happy new year to all, and a most successful 2006!

12.22.2005

Happy Holidays!

As my holiday gift to you, a link to an oldie but goodie: the 2000 North Pole Gazette. Which is still pretty fresh, all things considered....

12.19.2005

Sometimes its not Power Quality

Evansville IN - an interference problem in a Cath Lab....

Checked the touch voltages, the leakage currents, tried some isolation / floating things - some issues discovered but nothing easily resolved. Fortunately, it turns out that 12 cables between high frequency motor drives and the applicable motors (lots of high frequency!) were installed with the braided shields floating.

I watched the OEM and the local service engineer reterminate things so that the shields got grounded. And the problem went away.

It's less satisfying when its not the power, but its great that the issue has been resolved....

12.02.2005

RSNA 2005

Back from Chicago - my 2nd RSNA in a row and probably something like my 10th overall. Thank goodness I no longer work set-up (I coordinated the electrical stuff for one of the OEM's in a previous life) - the folks who do that and live in Chicago for two weeks are surely ridden hard and put away wet. Even when I did work the show I rarely stuck around for more than a day or two once the meeting opened. Thankfully, the weather was pretty good - balmy Sun-Mon, colder Tues-Wed, some rain in between (but no snow). I even got some Jazzercise in over at Mercy Hospital (Class #2790, and a huge thanks to Marcia for the welcome!)

Not too many power quality folks there: Staco, CAT / Activepower, and TEAL Electronics were about it. Lots of interest in the new TEALwatch power monitor - which will hopefully translate into some work for me.

To everyone I met and spoke to, hello - feel free to call or drop an email if you have power quality questions or issues. To those, I missed - there is always next year!

11.07.2005

Flitting Around

October saw me in Massachusetts (doing a presentation at the New England Society of Clinical Engineering annual symposium), in Baltimore (presenting a paper at Power Quality 2005), and in Irvine, CA (program launch training on the new TEALwatch power analyzer).

November seems thankfully a bit less hectic....although RSNA is on the horizon.

10.27.2005

Power Quality Conference 2005

When you go to trade show juggernauts like RSNA, its hard to take this thing seriously. The exhibit floor is small, the sessions seem to be about 50% infomercials for a particular product and 50% substance, and a lot of it is churning among insiders. I did make a few connections and get some good ideas - which are worthwhile.

I came in yesterday morning; was planning to stay two nights and leave, but I can not think of what to do locally; so I am gonna try to sneak out this evening. Yeah Southwest for having lots of direct flights to Hartford....if the travel gods are smiling I should make the 6:15 and be home by 8:00 pm.

On the plus side, yeah to Baltimore for doing the airport to downtown thing right. I jumped on the Light Rail ($1.60 except the ticket kiosk was down so it was free) at BWI and it dropped me right outside the conference or a few blocks from the hotel. The Hartford Courant needs a letter about that - we need "Scooty" (or whatever the heck Colin McEnroe was calling his light rail from BDL to downtown) to make Hartford accessible short of a $$$ cab ride, a bus, or renting a car.

10.04.2005

Top Ten Website Design Mistakes

I know web work is a side-light / boutique side of my worklife, but I found this to be helpful and enlightening...thanks to Jakob Nielsen

9.05.2005

Connecticut Sun - WNBA

Every so often I take off my power quality hat and put on a production support / graphics hat. This summer, I had a recurring gig working with the production team at the Mohegan Sun Casino, operating a graphics computer for the Connecticut Sun (WNBA) home games.

It's been a lot of fun...being behind the scenes at a professional sports event, getting to watch all the home games, running into the famous and semi-famous athletes and celebs.

And now the CT Sun are into the 2nd round of the playoffs - with an upcoming series against Indiana - and after that, maybe another shot at the championship.

GO GUN GO - GO SUN GO - GO SUN GO - GO SUN GO

8.31.2005

Hospital Conditions in New Orleans Worsen

An AP report by Adam Nossiter, on Yahoo, here
"As floodwaters rose around Charity Hospital, the rescuers needed their own rescuing.
Charity's backup generator was running out of diesel fuel.
and
"It's like being in a Third World country. We're trying to work without power....We're just trying to stay alive," said Mitch Handrich.

Just incredible.

7.19.2005

Fluke Mains Impedance Meter

Since the discontinuation of the ZM-100 Meter, we have occasional requests to quote these, or barring that, to recommend alternatives.

Fluke makes a similar device - Models 1650 / 1652 / 1653. You can get some information about this device here. My one caveat - this appears to be a device sold in Europe only - so you may need to hunt around to find it in the United States.

6.23.2005

Annoying Power Monitors

A client has recently contacted us about looking at some data from a Hioki 3196 Power Analyzer. Unfortunately, getting a look at the data is like pulling teeth - there appears to be no simple viewer software to look at things, and the official software (9524-10 PQA-HiView Pro) is hyper-protected with a USB software key / dongle.

So it's been a week of back and forth and Fed Ex bills trying to get access to the software. I'm not going to buy a $995 software package for a couple of hours worth of consulting to review the data and write up a report.

Hey, Hioki: If you want industry acceptance (and coincidentally, higher volume of hardware sales) it might be a good plan to put together a low end "reader / viewer" that lets people use the data. One of my clients in the medical OEM world has a fleet of 30 or so RPM meters. The fact that the RPM analysis software is pretty portable and not so fanatically guarded is a pretty important consideration to a field service organization where the meters will be shared among many service persons, and analyzed remotely.

I have no problem with keying your software in such a way that you need the dongle to talk to a power analyzer, or making certain features dependent upon the full license and key. But come on - are you in the software business here or the test equipment business? And do you want to ever be anything more than a niche player in the power quality field?

A good model for you might be Adobe - their Acrobat reader is a free download. So Adobe has given away a lot of free software, and not coincidentally become the industry standard for document transmission. And, oh by the way, sold a boatload of full Acrobat packages (and not inexpensively) to content providers such as myself to create the documents.

My two cents - still waiting to look at this data - it'll probably be another couple of days.....

2.15.2005

Killer RPM Applications and Tech Notes

Marc's Technical Pages; knowledge-base of Faultlink International, an independent electrical / electronics fault investigation & analysis consultancy.
http://www.marcspages.co.uk/nsd/index.htm

1.17.2005

eTRust ezAntivirus

Computer Associate's eTrust ezAntivurus program has become the standard here at PowerLines. Mostly because its almost transparent in terms of impacting processor speed and application function, it does its downloads transparently without popping up windows all the time, and it seems to work (have not gotten bitten in years)

And the purchase price / annual renewal fee is pittance ($20, this year)

1.06.2005

High Frequency Noise

Whatever happened to high frequency noise? Remember the BMI-4800/8800 high frequency noise feature? I know it was coarse, I know it was not standardized. Oneac used to have their little OneViewer that also was a useful tool. So....what happened? Was it a canard? Just too tough to quantify? Do we just assume that isolation transformers and filters are omnipresent, or that equipment is sufficiently rugged to deal with noise?

I recently went to a site that is having some power problems, and the suspected problem is noise from welding machines either radiated (feeder not in metal conduit) or conducted. But its hard to really know for sure with modern power quality tools - some sort "noise meter" would be helpful - so at this point, we are guessing....

12.30.2004

Mozilla Firefox

Has become the official web browser of PowerLines - not that I was all that PO'd at Mr. Gates and Microsoft, but I do like spreading my affections around. (I have also staunchly avoided Outlook as long as I have been receiving email)

That being said, I find that a lot of my coding (including the PowerLines website) is not 100% HTML compliant.It looks fine in IE, but not in Firefox. I am working on that; but the paying clients get done first....so please be patient.

And have a happy new years, everybody!

2004 Wrap-up

Well, the numbers are in. We processed 391 sites worth of RPM and/or environmental power audit data for one of our OEM clients in 2004. I am fairly sure nobody comes close to looking at that much RPM data, and certainly nobody does it more cost-effectively. If you have underutilized RPM power analyzers or are not getting the full benefit of these boxes, drop us a line - we can probably help!

12.06.2004

The Montreal Massacre (1989)

Today is a day that is set aside to remember the massacre of 14 women who died because they were trying to get into a male dominated profession.

In 1989, Mark Lepine entered the Ecole polytechnique engineering school in Montreal and walked around the school shooting any women he could find. He ended up killing 14 of them and then himself. He didn't feel that women should be able to become engineers.

I was only a few years out of an engineering college at the time (where the M:F ratio was 13:1 in my graduating class), certainly the incident was less meaningful to me then than it is now. For the past 15 years, Dec. 6th has been set aside in Canada to remember these women and to remember all acts of violence against women.

11.30.2004

RSNA

Visiting Chicago this week for the annual Radiological Society of North America (RSNA) meeting. Working with my client TEAL Electronics. PowerWare and Caterpillar are also here, but mostly not a lot of power quality vendors. It's mostly medical imaging companies selling to the radiologists, rad techs, and dept managers, but there is a lot of internal churning going on.

It's been great seeing old colleagues; I have not been to the show in 4 years. Also, lots of interesting PQ projects and programs are getting discussed, lots of networking and renewed relationships. Good stuff.....

11.23.2004

What are the odds....

I just went through the proceedings from the recent Power Quality conference.
62 Men. 3 Women (myself, a recruiter, one other woman). 8 Ungendered (unfamiliar names or just initials). Sobering.

11.21.2004

A Neat Toy

Picked this one up for the Power Quality conference. It's a wireless, handheld mouse called the Gyration Ultra GT. It has a range of about 30' (most wireless mice go 3' - 5' max). It works on the desktop *or* in the air (gyroscopes or something). It's pretty cool. And best of all, the mouse thing seems to work and be useable - which is pretty rare with these presentation tools. About $80.....

11.17.2004

Deja Vu All Over Again

Compare and contrast:

Wrong Prognoses Aggravate Medical Imaging Problems
Power Quality magazine, March/April 1991

Case Study - Blurry X-Rays
Dranetz-BMI Website, November 2004

10.23.2004

Hioki Leakage Current Meter

A new tool in the arsenal. I recently was doing some work with Leakage Current for medical equipment. The Hioki 3283 Clamp-on Leak Current meter was very useful. With a selectable high frequency filter, a MIN / MAX hold feature, a sufficiently wide jaw diameter, and 10 uA resolution, it was great to measure both ground currents as well as net currents across the phases and neutral. Highly recommended.