Predictive motor testing in the field

I was wanting to know if anyone has an opinion on which test equipment is better for filed testing of AC Electric motors. There are a lot of vendors out there and I want to make sure our money is spend on the best equipment. I guess the three main companys I have been looking at are PDMA, BAKER, and ALL-TEST. Any help would be greatly appreciated.
Original Post
We have four PdMA testers - two Emax and two MCEMax.

PdMA is a great company with a great technical support staff. Their maintenance contracts are reasonably priced and include the calibration of the tester and three days of onsite training (travel and expenses separate), among other things. The PdMA technology is straight forward and the company seems motivated to keep improving its product.

I cannot comment as to the other vendors, only that RA-Entek has a tester that integrates with Enshare software, but I was advised (being an Enshare user) to not even waste my time in looking at it.
I have used the PdMA MCEMax and agree that it is an excellent tool. I have also used the All Test Pro MD kit and again feel it is an excellent tool. Another major player in the field of on line testing is Framatome

My advice is to invite all of your candidates to show their wares at your place to your maintenance personnel. This should give you a chance to make an informed decision.

It might be instructive to pick equipment motors for testing that have known faults that are not severe enough for you to have repaired. I did this with the MCEMax when we were evaluating the unit. A critical fan with a belt problem was one of the units tested and the defect showed up clearly. Made believers out of some people.

Ken Culverson

I used to be the General Manager at ALL-TEST Pro. I am now an independant consultant and the Executive Director for the Institute of Electrical Motor Diagnostics, Inc. (a new not-for-profit professional society working with ISO on motor diagnostics certifications).

Here is what I recommend, as each of the technologies has their strengths and weaknesses as demonstrated in a class of users of the different technologies in Chicago a few weeks ago.

Rotor Analysis offline: ATPro and PdMA use inductance rotor tests in order to determine broken rotor bars. Quite successful.

Rotor Analysis online: ATPro, PdMA and Baker all use current signature analysis for rotor bar testing.

Winding offline tests: PdMA focuses on insulation to ground testing with low resistance and inductance testing. ATPro focuses on developing winding shorts with a low voltage test for turn contamination and an insulation to ground (megger-type) test. Baker focuses on insulation to ground, resistance, hi-pot and surge comparison testing.

The PdMA and Baker use laptops in brief-case style carrying cases to collect data, with the Baker having seperate online and offline systems. ATPro focused on developing hand-carried test instrumentation.

If you wish, I can provide you with phone numbers of users of each of the technologies. However, I would still recommend that you make arrangements for each of the instrument companies to come in and demonstrate. Regardless of being told, by the instrument companies, their opinions of each other, just be assured that they are each good companies that will focus on their own strengths.

If you have any other questions, please feel free to email me, including for a few names of users of each technology:


Actually, planning on two more at Dreisilker this year. I have run of the shop, equipment, dyno's, machine tool test equipment and areas, and they usually have pretty much any kind of motor you can think of there. Besides, their staff takes care of making sure everyone is fed, etc.

In the last class we had PdMA, Baker and ATPro equipment. Was an excellent opportunity to compare and contrast the technologies in a user-only environment.

Originally posted by Alan King:
I was wanting to know if anyone has an opinion on which test equipment is better for filed testing of AC Electric motors. There are a lot of vendors out there and I want to make sure our money is spend on the best equipment. I guess the three main companys I have been looking at are PDMA, BAKER, and ALL-TEST. Any help would be greatly appreciated.


I'm impressed with the several good recomendations you've received from this post.

I may be a little late with this suggestion, but our facility actually leased test equipment from vendors (one at a time) to use in our facility for a good trial run on our equipment. The vendors actually came in and gave us classroom and in the field training with demonstrations to get us started.

As in most any testing situation, the application is of utmost importance in determining what equipment to buy. In the proactive predictive field where a lot of test data is accumulated, I would recomend a unit that includes a computer to help store and trend that valuable baseline and historical data.

If however you desire an instrument for a reactive type on a "as requested" basis, something more portable might be better utilized.

I wish you good luck in your venture and just want to fore warn you that you won't believe the amount of problems these units are capable of finding, which by fixing any one of them could very possibly prevent an outage.

Knowing how each of the company's equipment does there job may be enough information of some experts, but is there any way you can point out positives and negatives for each, as it pertained to question, namely field service testing for predictive maintenance?
having used both the PdMA MCE+EMAX and the ALL-TEST PRO MD both have merits, but the final result is that I would rather go back to the PdMA system. It has the ablitiy to query the data base for pointed data searches. The All-Test system does not. with the release of the new GOLD software PdMA seems to be the better choice. side note DON'T purchase a system on cost alone, you will regret it later.
We went with Baker- handy since they are located just 45 minutes away.

I like their off-line motor tester- AWA2.2 Surge/HiPot/Resistance Tester. It automatically tests in stages starting with resistance, then meggar, then hipot, then surge test. They have a higher potential unit but we focus on 480 volt motor testing here so 2.2kV is fine and more cost effective than the higher voltage unit.

I've seen their on-line tester and like it too, although we haven't purchased it. I went to a Baker training class for the online tester and found it didn't do real time chart recording very well. If I spent money on an online motor tester I also want it to record as a programmable chart recorder (time of day start/stop, trigger, etc) so I can use it as a trouble shooting tool for process systems. I think they may have addressed my concern, but can't confirm it for this reply.

I saw All-Test's offerings and thought them to be limited compated to the capabilities of the high end testers. It might be better than nothing if money were the primary concern, but if analysis outweighs money, go with a high end tester.
I have not used the All-Test on-line system, however I have been using Framatome's EMPATH systems for almost 10 years now. I believe All-Test basically uses the same software, developed by Framatome (now Areva).

The EMPATH 4.3 version can definitely do database searches and has pleanty of options for filters. It takes some time to get the hang of it, but subsequently it works great for comparing similar machines as well as trending.

Last time I checked, PdMA did not have a no. of features that the EMPATH does, viz. power spectrum & waveform, post-processing capability of the signals, unlimited enveloping filters and automated driven load & DC motor analyses. Some may have come in recently, please advise.

Bottom line - do not run down a product just because it costs less!


This is a great thread. Could the users comment on the number or percentage of motors they discover that indicate electrical, winding, or rotor problems:

on a troubleshooting basis?

on a PdM basis?

What are the accepted PdM test intervals for critical service or high value motors?


Dan Wise
each user or company should explore all options, weigh the the results, and choose the equipment that fits the needs. if infield data collections time is an issue the All-Test is a very fast collector but the time to view the data at the desk is longer. the All-Test automated results are not always correct. the Pdma unit displays the results as each test is taken, allowing for infield data review with a quick note for more indepth review needed.

all in all each of the testers have something to offer that the others may not have or do it differntly.

try as many as you can and pick the one that fits your needs the best.

Have a good day!!!!!
Question: "I was wanting to know if anyone has an opinion on which test equipment is better for filed testing of AC Electric motors".

The choice of Motor Test Equipment depends on what ones objective is when testing motors. Do you need an equipment just to troubleshoot your motors and let you know if the motor is good or bad or are you looking to collect data and do the root cause analysis and prevent further failures. Some might be interested in a complete motor management system, which would allow testing, trouble shooting, root cause analysis as well as maintain test data for trending and comparison. Further one would want to have the capability to transfer data to another MMS software running at their facilities to incorporate / share data from other technologies (Vibration, Thermal Imaging, Oil Analysis), prepare test schedules and reports for Engineering or Management.

Best is to narrow down you choices and decide what is the objective you want to achieve by testing your motors and what benefits you are looking for, a sustainable motor predictive maintenance program, Reduce Motor Repair Cost, Reduce Unscheduled Repairs, Reduce Down Time. Basically no one wants their motors to fail when they are least expected and without any warning.

As a service company we use PdMA MCEmax and have upgraded to their latest software MCEGold, it is a complete motor / asset management system, which is the best in maintaining our customers motor inventory, test data and has now excellent reports features. One of the capabilities I like best is being able to generate separate motor list from the database to assign work to our service techs.
Inclined to agree with you Alan...I've been looking at PDMa myself, but on a portable and a cost effective basis. I just began looking so I'm not really sure what is offered out there.

We took a tour to a local motor repair facility a year or so ago and this is where I saw the PDMa in action. Has a nice clean signature with sidebands, and as the side band amplitude increases this shows the severity of the rotor bars. I also need a way to do off load testing if possible. That would be really nifty!!

I'm also looking to find other internal motor problems as well, leads, windings, shorted laminants etc, which would caue that high 1X vibration signature...

Keep us posted as to what you go with, and drop me a line..

Rodney Bell
Baton Rouge, LA
I am a Long Time Reader,First Time Poster, but this topic was just too interesting.

No matter who you talk to in our field, everyone seems to have their favoruites, be it PDMA, Baker, Alltest, the list goes on, and most of us feel strongly about our choices. And no matter what is said, there has been a lot of research and development put into each of these.

I have had experience with most of these Brands [previously a Field Service Tech for Large Motor Shop, now involved with a strictly Service/Testing company] and personnally I choose the PDMA MCEmax system hands down... not to imply that you should

1st off: Review your current situation (what technologies or practices do we currently use)

2nd: Set goals for your program (DO I want to randomly test motors as I become suspicious, or make the testing time based or even take it to the next level )

Ask yourself, "What do I want to do with the data I collect?" (this is where I was sold on PDMA)

How you answer this question will help make the decision of equipment brand much easier.

3rd: Meet with the vendors and allow each to make an initial pitch. They will supply you with tons of info. I like to see which approach the vendors take in presenting their product. Are they proactive in developing their own technology or rather reactive to their competitors releases.

This was my major complaint with the Alltest (vendor not equipment), I heard "we can do this just like Baker/PDMA" a little too often.

4th: After reviewing the information and cases presented, do some in-field testing. Try them all... you'll quickly find features you like and dislike.

Are the tests safe... can they harm the equipment? Get it in writing

Also, get supporting info on standards like IEEE, NEMA, etc and question how the equipment meets these guidlines. (Surge Tests - New or recondition motors... not meant as a field test)

7th: Do some research and talk to other customers (infact your doing that now).

Ask how they felt the post-purchase support was? Were they satisfied, are they still?

Most importantly Don't let $ be your determining factor. An effective program will recoup the costs very quickly.
I am making a comparison between EMPATH 2000 & the EMAX / PdMA and also with the on-line motor monitoring developped by Baker.

My goal is to find the best equipment to analyze and realize predictive maintenance on induction & DC Motors and also on Transformers up to 50 MVA.
Prices given y EMPATH 2000 seem low compared to the others.
Do we have had any positive or negative comments from customers on these different systems?
Thanks, Sophie
I have been using the EMPATH (old & new) for over 8 years now and am quite happy with it.

Recently, I had bid for a service contract where the competitors used PdMA & All-Test systems, had made a comparison then. It may seem biased and I welcome feedback from other sources.

There was a study between PdMA & Baker regarding motor efficiency calculations, that too is attached.

The current EMPATH software does have some drawbacks regarding automated analysis for low speed motors (750 RPM & below) & bearing analysis. I believe these are supposed to be corrected in the next software version. I still prefer the old EMPATH (002) compared to the new one though.




Thank you Aditya for your answer.
It is foggy to me...
I read the attached documents and it seems that the Explorer is much more better than the MCe Max of PdMA.

I like the Manager from Framatome Don Ferree; he seems to listen more the customer needs.
In the other hand, Baker & PdMA cover a large range of customers compared to EMPATH 2000.

There is a big gap between these 3 companies; I cannot make a mistake investing in the wrong on-line system.

Can you give some insights about the old EMPATH (002), compared to the new one. Why this version is better than the last one?

What I fear is that EMPATH 2000 fits more for Nuclear Facilities than for other Business like Cement, Cars, Food, Areospace Companies but I don't get why?

I spent two intensive days reading and analyzing manuals users for the EMPAT 2000 and my conclusion was that the for a predictive Maintenance the softawre is weak.
Maybe I am Wrong!
Other Comments are more than welcome!

Today, in France it is snowing!

I have only seen the PdMA products at trade shows & played around with their software, nothing exciting over there. Baker's latest version for DC motors does seem exciting.

I know Don Ferree for many years, he sure is a good guy to work with. What I like about Framatome is that they are up front: no hidden costs or accessories, no extra for additional software licenses or maintenance agreements. Besides, I can get the latest updates on-line. I know that Framatome is relatively unknown, but they were working on this stuff way before anyone else (back from the ORNL and B & W Nuclear Technologies days).

I use our EMPATH units mostly for petrochemicals, power, fertilizer, cement, chemical & steel plants and have not had any issues with the tests. I guess they just don't believe in advertising.

The new EMPATH 2000 has many new features compared to the older EMPATH 002. However, the older version had a much cleaner & simplified user interface, less clicks required for the same operations and was glitch-free. Cannot say that about the new version. While our people got the hang of the old one in days, the new one takes a few months to be comfortable.

I did not attach the comparison between the EMPATH, All-Test & PdMA units earlier, the same is now attached.




Thank you to All of You,

You are wonderful!
I spent the last week to study EMPATH 2000, EXPLORER Series & MCE max. I was wondering if a software version on-line and /or off-line exists able to do both electrical and vibratory analysis.

European Businesses Plants are looking for this kind of product to diminish their costs; moreover, that spectral ( sinusoidales) curves analysis are complementary and that phenomena (squirrel cage) are similar.
This week, I will study what SKF offers.

Any Suggestions!
take care, Sophie
I have heard from Don Ferree that they are going to merge the EMPATH with the Metravib (stell dB) product. James Zhuge of Crystal Instruments too is working on a similar project. No clue about when either of those two might be launched though.

Explorer does take vibration measurements, however it lacks portability and I cannot see it being used as a vibration data collector.


Hi Guys,

Who has ever conducted or read a Marketing Survey about the market & products'repartition between the huge groups like Emerson, Bently, Baker Instrument, PdmA?
My job conducts me to analyse the Motor Diagnostic system off-line & on-line and also the companies that offer a combination of electrical & vibratory analysis on strategic Induction and DC Motors.

Have you ever established a list of the major causes of motor failures ( bearings, entrefer, misalignment & bent shaft, ground isolation, turn insulation, bracing, frame ) and the costs associated with.

Do you think that companies such as Baler, PdMA, Framatome must market internationally their products through a condition monitoring /predictive maintenance and not through electrical instrumentation channels.

I heard that a company should develop a combined system (VA + ESA). To your point of view what should be the best channel to inform people like you and sell at the optimum their system?

For instance, until now, they do not pertain to any big association like the IEEE.

Have a good day,
Sophie, I'm curious, what does your company do?
(I didn't like the way my original post read, so I edited it.)

Questions for you to consider:
1) Are your motors started often or do they run continuously?
2) Do your motors start loads with high start-up torques?
3) Do you have large motors or mostly smaller, say, under 175 hp?
4) Does your company have a mechanical vibration program? If so, is it a mature program? How ofter do they take readings?
5) Does your company perform off-line testing on your motors? How often?

My personal feeling is that these questions play an important part of making your decision. Your answers can indicate purchase, sometimes justify holding off, or even not making the expensive purchase.

For instance, many of our most important motors run continuously in an HVAC application. Many of the other important motors are controlled by VFD. I doubt you'll ever see a rotor bar problem in either of these duty applications. If there ever is, our mechanical vibration program will pick it up easily. Broken rotor bar detection is usually a big selling point of on-line motor tester salespeople.

A good mechanical vibration program will pick up pending bearing failures much more quickly then an online motor analyzer. Same for soft foot, misalignment, loose belts, bad couplings, etc.

Most of our remaining motors are in a very clean, regulated 20C temperature, 50% humidity environment and we are a batch operation so motor testing can occur between batches.

Many VFD software programs now come with a monitoring program that will track V/A/Hz and nearly any other parameter the VFD is capable of. This is useful for tuning the drive to the process. This is another big selling point.

I've been suggesting that manufacturers of online testers combine an effective chart recording feature in their software so I can program the unit to record from a programmed day and start time to a programmed stop time instead of being solely event based or record motor start for a programmed (but finite) time period. It was suggested that I give the unit a continuous trigger and repeat the time period over and over as a work around. A free entry day/time would make the unit more useful to troubleshoot process systems. But now the Fluke Power Quality Meters have a funtion to do that.

I purchased an off-line motor tester , but have not made an online motor tester purchase for the reasons stated above. If I was in a different industry where our motors are in a tougher duty application or totally inaccessible I might put the online tester at a higher prioity than I can justify currently.

I just wanted to put a slightly different perspective on this thread.

Hello Sophie,

I found two articles in French. They may help you address your efforts. (I just could attached one, I'll send you the other one later).

Feel free to e-mail me at my personal account, I can answer your questions in regards the PdMA technologies. Feel free to write in English or French.


Hebert Libreros



Here is a study that was performed on the industry in 2003 as to the status of the industry, at that time. All of the manufacturers, including PdMA, Baker, ALL-TEST Pro, Areva (Empath) and Iris (CS Meter) have been making advances since then and the market has opened up.

IEEE has finally issued the IEEE 1415-2006 on May 1, 2007, which covers all of the common diagnostic technologies used within industry for maintenance and troubleshooting of induction machines.

Each of the technologies has their strengths and weaknesses. The selection actually depends upon your needs. Most have not included vibration as part of their technology, from a true analysis point of view.



Sorry to bump such an old post. I am new in my company's reliability department, in-fact, I am kind of a pioneer in my plant for electrical reliability projects - I have used a lot of the information I read here to get a great starting point

I have spent quite a bit of time over the last couple months looking at the various motor testing softwares out there, and after meeting with some of the vendors, my company has narrowed it down to the PdMA MCE Gold, and the Areva Empath 2000. Both softwares seem to be quite beneficial to our company, assuming we develop a good practice of using the equipment.

My question is to those of you who have used either system: Can you provide me with positive or negative experiences with MCE Gold, or Empath 2000? Any and all feedback will be greatly valued, we are very close to making a decision.

Thanks in advance
Dear All....

Greetings for the day....

I wanted to know about the Motor current signature analysis,when i am searching the details i had come across AREVA 's EMPATH 2000 for condition monitoring of electric motors based on its load current analysis.

Anybody used this instrument....pls provide how to handle and intrepret the results of the instrument...also pls post some details about the important result we have to look from EMPATH to comment about the motor condition....and its significance pls...
The on-line equipment from Alltest, Baker , Empath, and PdMA are all pretty good. Each has its benefits. One new thing to consider is the implications of NFPA 70E. Many of my customers no longer can connect to the voltage leads without an act of Congress. If you have this issue, make sure you purchase a tester which allows you to obtain current signature analysis without connecting voltage leads or you will need to install the quick connects on the MCC front panels.

It is my understanding that the All Test on-line tester uses hardware from Power Sight and software from the Areva Empath. I am not sure if the software in the Empath and the AllTest are absolutely identical.

I do not own on-line testers from any of these companies. IMHO they are expensive for what they do. Instead I purchased a significantly less expensive power analyzer and developed a Current Signature Analyzer using clamp on CTs, a portable scope and off the shelf FFT software. This works every bit as good as the products costing $10Ks for a fraction of the cost. Plus, with the scope and an RF CT, I can easily perform on-line partial discharge insulation testing while I am at it. Much better combination of tests than any off the shelf product available today. But, it does require more technical understanding than the off the shelf products.

Regarding off-line testers. I own both Baker and All-Test and have used PdMA. All of these products have good Meggers. So if the issue is damp or dirty insulation, they perform equally well. For troubleshooting already failed (shorted) turn to turn insulation, the Baker and AllTest are better than PdMA because they can more easily differentiate between insulation problems and rotor affects. But, IMHO the Baker is the best off-line tester for predictive insulation testing because it has the capability to use high voltage Dc hipot and impulse to detect weakened (not yet shorted) ground, phase and turn insulation. The Baker will detect the <5% of the problems that the others will miss. I use the Baker for testing from the MCCs and easy access motors. And I use the smaller, lighter, battery powered AllTest when I need portability.

Good testing everyone!

Randy Keener
Torq Engineering
It is an excellent thread and found very informative things so far.

My exp with PDMA offline tester:
PDMA laptop and battery max temp limit is 35 DegC which is not at all suitable for environment like middle east. where MCC design is not allowing the testing from MCC end.

Dear Aditya and others:
Can you guys please provide latest update on Offline Motor Management tool which we can use in harsh environment ( temp nearly 50)with high humidity upto 100.

you can mail me on

Hi Khatri,

I've used the All-Test instruments regularly in Saudi; 50C is not a problem. The humidity generally is much lower though.

I still think that PdMA/All-Test kind of instruments are good for LV motors; but for MV motors you need tan delta & PD. I would invest in those first, you will get much more value for your money. Surge test is pointless as a condition monitoring tool; basically a GO/NOGO test.


Originally posted by RKeener:

Regarding off-line testers. I own both Baker and All-Test and have used PdMA. All of these products have good Meggers.

The All-Test Pro testers that I have used did not have reliable meggers, in my opinion:

1. They did not display actual test voltage.

If, for example, you are conducting a 1000V test, and your test voltage drops to 800V, then the test is invalid, unless the resistance shows that the winding is shorted to ground. Most meggers display actual test voltage; the All-Test Pro meggers did not. They only displayed the voltage setting selected by the user.

2. I have watched All-Test Pro meggers pass windings that quality meggers failed. I also noticed that the displayed resistance values climb much faster with the All-Test Pro than with other meggers.

Out of curiosity, I measured current generated by four or five meggers with the leads shorted together. All others - even cheap meggers, costing less than $300 - produced around 1.6 milliamps. However, every All-Test Pro tester that I measured produced around 0.6 milliamp. I believe IEC 61557 specifies a rated current of 1 milliamp here.

3. The AT33 series motor tester differs from previous All-Test Pro devices in that the device can be used while it is being charged. However, the insulation resistance reading changed dramatically when the device was plugged in and charging.

4. The megger function locked up regularly (the screen froze, and the controls would not respond) on all All-Test Pro devices that I tested. Fortunately, the devices came with reset buttons, which were handy, but let's face it: most meters do not have this problem to begin with, and do not require reset buttons.
Hi Jack,

Which is the IEC 61557 subsection that mentions 1 mA? I went through some; could only find an upper limit of 10 mA. This (61557-8) was however for IT systems; not motors.

How is your experience with the AT-33? Did you pick up insulation faults with it? Would you recommend I purchase it or not for condition monitoring of LV motors? There are lots of techniques to test MV motors; but almost nothing for LV motors.



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