Five days training with one famous LCR Agilent U1733C

[Kiriakos GR]

Five days training with one famous LCR, one great experience even for an industrial electrician :-)
I will have the joy to explore this top of the line Agilent LCR U1733C for five days.

And I hope to discover how useful one LCR could be at the hands of one Industrial electrician.

There is capacitors in lighting systems, working as electrical noise filters ( Cos F improvements) .
There is capacitors almost in every motor, and if they turn bad, in order to find out the truth you need to replace first the old, and if the problem is not there, you have just thrown your money away.

All those answers and even more, is what I plan to discover very soon.
   

[Kiriakos GR]

Since the first day that I got my first Agilent U1272A (about a year ago) I was scratching my head of why it does not agree with the measured capacitance that my FLUKE 28II measures.

The FLUKE 28II (87V) was always measuring higher values, not a major difference but always was there.

Usually the naive and fresh user of multimeters will believe that is something wrong about the calibration and he will just blame the meter.

His mind will never go or think, about the testing frequency that its multimeter uses so to test the capacitors.

The LCR meters are something that forces your mind to wake up, as they do have selectable frequency about capacitance testing, the specific Agilent U1733C haves 100Hz as minimum.

Ok and what about the multimeters?
Well I got triggered to add my own frequency counter in parallel when those multimeters are measuring, and my findings are impressive and in lighting at the same time.

Usually the electrolytic capacitors that are in bad shape, they dislike high frequencies.
They will measure fine at low frequencies, but at the higher ones, their capacity will read as lower when they will be tested.

Now after this intro, I will write my first test results.

FLUKE 28II (Test freq 2Hz) capacity 256uF
Agilent U1272A (Test freq 10Hz) capacity 241.5uF
Agilent U1273A (Test freq 15Hz) capacity 240.3uF

LCR U1733C (Test freq 100Hz) capacity 223.5uF

Capacitor 220uF 16V

Lesson No1: Never blame your multimeter if you are unaware about the working frequency that it uses so to measure capacitors.

Lesson No2: There is no chance the FLUKE 28II to agree with one Agilent U1270 Series, due the very low Test frequency of 2Hz!!

I had become wiser in just one afternoon, more tests results will follow soon.

[ElectroElvis]

That is nice peace of equipment. like your U1272A over the U1273A heh normal display is much nicer:)

Ok to the topic. My personal opinion on LCR meters results of measuring capacitor and result of for example U1272A from same company is that factory is intentionaly misscalculate the reading on ordinary DMM like U1272A so they can market ther dedicated LCR meter better. Ok I do understand that frequency has special role here but software correction could also be applied with some simple math to get same reading.

Specially because U1272A and U1273A are both firmware upgradeble this can also be just software calculation nothing more, but that is just my opinion based on previous articles I have read and also from your picture you attached. Two DMM different models almost spot on same reading, but LCR has different one

Cheers

Elvis

[Kiriakos GR]

The easy Firmware update on those U1270 series is something that have been misunderstood even by me.
Agilent does not see that as one way to add extra capabilities, it is just a practical way to add corrections if ever needed, with out the need the multimeter to be shipped back.

About the capacitance measurement with multimeters, it looks that this function is the only one that the manufacturers they do not follow any standards about the testing frequency, that is very important.

I would expect because of the base AC 220V frequency of 50-60Hz, that follows the voltage when it gets transformed by a common transformer in to lower volts ( about making a DC power supply for example, which the electrolytic capacitors will come to further filter it after the simple diode)  that the testing frequency of one capacitor it should be tested at 120Hz as standard in all the multimeters.

And theoretically the LCR or better the ESR will get in the game to test capacitors who work in higher frequencies like  Audio applications or pulsing PSU.

In general the capabilities of the portable multimeters of some value about capacitor measurements they should not be that crippled.   

Positive impression from my first comparison is the part that Agilent use higher testing frequencies in their latest meters. 
   
 

[Kiriakos GR]

I have start to feel like a young kid with this LCR at hand,
I could never expect or imagine that it is so fun to using it. 

In my childish question of what will happen if I connect a speaker to it ?

The LCR reads the 8 Oms (internal resistor), and it sends to it 1KHz frequency that is amplified enough so to be audible from the speaker it self.

This is an amazing find, I bet that all of those who do speakers repairs or installations of car audio systems,
they would love to have this LCR as portable speakers test source.
Not to say how easy it is, to locate speaker cables like Front / Back or Left/Right speaker,
by using as source the U1733C.

         

[Kiriakos GR]

Truly the LCR in one invaluable tool which looks more like a Swiss army knife,
the sum of the measurements that it can do is truly enormous.

Agilent offers 87 pages of user’s manual and still looks short to me.
I would expect more generic information’s related to the ESR (capacitors testing).
Some one should help all those people who just like to use a very specific function with some extra guidance on the subject. 

As negative I found the missing examples or theory about the evaluation of the status of one capacitor, in relation with it internal resistor.

One simple chart which would explain what to expect from one capacitor at 1000uF capacity as healthy conditions, it would be more than appreciated.
And this is just an example.

I have test lots of capacitors, and found internal resistor from 0.040 Ohms up to 16 Ohms (16.000).
Yes the high internal resistor goes together with a significant capacity loss, and so you must be blind if you are unable to say if your capacitor is good or bad.

My point of view (or suggestion) will be that those User’s manuals they should also deliver and one portion of basic theory, other than mentioning the functionality of those button.

About other useful functions for example:
1)   measuring dissipation factor
2)   quality factor
3)   Phase angle.

I will just not get in there, simply because a higher load of knowledge is needed for the further understanding of those measurements.
For example if I was servicing exclusively three phase motors, the Phase angle measurement it would be considered as invaluable to me.

 
In the question of how useful one high quality LCR meter will be at the hands of one electrician, I think that I have some answers about that.
But there is also and another key question for every electrician and this is:
Do you like to expand your own theoretical field of knowledge?
Translation:  To read extra books or web text or watch videos on Youtube, so to expand and learn few extra principals found in the school books about electronics?

The specific LCR comes with one self detection mode of what is connected to it.
And automatically selects range and function, and so it helps for fool proof measurements at no expert hands.

I did find it useful about identifying damaged capacitors and as must-have if you need to clean your own box that you collect in it, all the used capacitors from old projects.
Testing speakers was another simple example about usability, finding out the internal resistor of one speaker is just the top of the pyramid.
Very few and expensive multimeters offers at the low Ohms range the high resolution that the U1733C haves, and so this LCR works as Ohms range expander in your tool box.
Or better as one magnifying glass about low Ohm values.

If what matters to you most is the diagnosis of the windings found in single or three phase motors, the LCR is the tool that it does even more measurements or tests of what a multimeter can do.

For the price, I will agree that the 300$ or Euros is a bit salty.
But from the other hand this tool is there to perform advanced measurements,
It is up to you and the style of your work to make your mind if this tool is for you as well spend cash.

   
Personally I do have interest in low Ohm measurements’ and I have buy portable and bench type meters (FLUKE 8012A) with rich resolution in Ohms.
About testing capacitors I am not organized that good, the U1733C is great but I prefer to wait until to see more options, especially about the pricing factor.
If it was hovering at 130Euro I would just buy one, with out second thoughts. 

[Phyllomedusa]

OK, you caught my interest .
I had been aware of the different measuring frequencies and the different reading they offer, but I actually never thought about the frequencies used in my handheld dmm.
So I took my meters (Agilent U1253B and Voltcraft VC 670/Wens 53) and wanted to look at it on my scope......actually I never want to miss a chance to play

So the Agilent is about 10Hz as test freuency and my old Voltcraft(conrad) was a bit of a surprise. I expected it to be slower but the scope showed a much higher test frequency. It is about 130Hz. I attached the reading for you to have a look.
It should have been said, that I used a BNC-Banana Cable parallel to the test probes with alligator clips on my Agilent and touched the contacts of the Capacitor on my Voltcraft, as this one just has a slot in socket for capacitors.
So there is a lot of cables which surely have influence in the reading, but as I only wanted to see the pattern and compare it, it's fine for me.