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Looking at slide #3 of the 5th lecture, I'm reminded of the concerns you might have measuring a high-side shunt in a high voltage/high power circuit.

If you're measuring with a scope or data logger, you need to use 2 single-ended channels, one on each side of the shunt, because a scope or data logger normally have a grounded (earthed) chassis. If you try connecting the ground clip of a single-ended scope channel to the low side of a shunt, you could destroy the instrument due to high currents flowing from the UUT through the instrument's chassis to earth.

If the instrument's channels are differential or if you have a differential probe, then you can measure the voltage across a shunt with one channel of the instrument.

Floating a scope or data logger's power source is a bad idea if you're attmempting to make a high side shunt measurement with a single channel because the instrument's chassis could be at a high and dangerous voltage with respect to earth. One brush against the instrument and you get a potentially lethal shock.

Iron

Trying to measure Energy Consumed.

Iron

How Sine Like? Measuring LDC -- Electric Power company lines. Good Question.

Iron

I measure just the dc side

Iron

no I havent heard of an SMU but I do have a killawatt

not interested that much in ac 

Looking forward to completing the week

Picking up the last day

@moderator - average and peak on a per-circuit basis

Iron

@moderator - relatively clean (using oscilloscope)

Iron

Great to have access to the recorded sessions

Iron

Missed the live lecture...

Iron

Good weekend to all; see you next time

Iron

Thanks Bill; very informative session

Iron

I use a scope to look at sine wave

Iron

Got in a bit late. Good series thanks.

Iron
Thank You for the INFO.
Iron

Thanks Bill, a very good series

Iron

Agilent has some good instruments

Iron

To all, have a good weekend and see you next time.

Iron

@ jojo - It depends on your Voltage range. Price goes up with the voltage. Get on line and search. Thers a lot to chose from.

Iron

we'll be here another few minutes, then we're "signing off" as we used to say in radio land.--Bill

Blogger

Have a good weekend to all!

Thank you for answering my questions.

@rswanson, I'm sure I saw analog circuit fragments built around opamp log - multiply - anti log circuits for square and square root.

Iron

rswanson: using an op amp to square an analog signal is fairly easy--check app notes from any major analog vendor, it's a classic circuit configuration. I know some early but still valid app notes from ADI show how to do it.

Blogger

@AriQue thanks, any model off the top of your head? and is it affordable? i.e. under $3K?

Iron

Because of the square term in the power equations, is there a op amp configuration that squares the input signal, as opposed to scaleing it

Iron

Yes that information was helpful to me also

Iron

To all: remember, when you talk with an experienced vendor, they will raise issues you may not have even thought you needed to be worried about--but hey, it's worth listening to what they say, even if it may not be a concern of yours in the end, in your situation.

Blogger

All the Electronic Equipment Manufacturer now sell SMU. (Hp) Agilent started SMu's

@jojo Agilent and Fluke have a good Impedance Tester.

Iron

rswanson: by analog, I meant a basic op amp scaled to transform the input signal x the resistor size--you don;t really need to do a true multiplication of two unknown analog signals. And I think vendor like Microchip do make power-measurement ICs which combine analog and digital blocks in one easy-to-apply device.

Blogger

GREAT. Thanks very much for the info.

So Rich, when do we find out if we get a Design News Tee Shirt?  LOL

Iron

Suggestion to the moderator: Have the comments add to the bottom of the list or something so that when comments are made, the page doesn't skip and it's not so hard to read the older posts

Iron

Looks like for some of you, learning about the SMU was a good thing! Agilent, Keithly make them, I am sure there are others as well. And maybe NI has some simialr setup, too, don't know.

Blogger

Thank you for the presentation Bill. Other than some issues with audio, I enjoyed it.

Iron

In a previous lecture, Bill you mentioned using an analog IC as opposed to using "all digital" to determine power. Would you mention one or two of the IC's you use?  Thanks

Iron

We have a Keithley SMU that really comes in handy from time to time.

Iron

Thank you.  Have a great weekend and good luck with Hurricane Sandy if you are on the East Coast

Iron

SMU was Stimulus - Measurement Unit in some of the larger ATE installations I was involved with. Same kind of idea, but certainly not bench top eqipment, more like a 19" rack cabinet.

Iron

Your right about the insulation and leakage.

Iron

Look at the Agilent web site.

Iron

Anatoliy186:  a good electronic load should look resistive--but check the specs.

Blogger

Great Lecture needed this 10 years ago.

Iron

kV and uA--a tough combination. It's all about insulation and leakage at the same time, I'll bet.

 

Blogger

Is there a measurement tool that can measure AC impedance?

Iron

yes. they are great. check NI for details.

I have been using SMU's since 1984. I work for a Semiconductor Co.

Iron

Have n ot heard of a SMU previously.

Iron

I'm not involved in AC power measurement right now, but I have a few more valuable problem solving tools to use after the sessions this week.

Iron

so can the SMU measure AC impedance?

Iron

Aware of the SMU but most of my work has been at power levels they will not easily provide.

Silver

Not sure if SMUs can do AC line impedance--don;t think so.

Blogger

good bye all great webinar

 

Iron

Thank you for the info

Iron

No, I have not heard of a SMU before. Thanks for the class, I learned several things.

Iron

OK, we'll look at the chat soon--participants are welcomed to chime in with their answers as well.

Blogger

Thanks Bill and Rich.

Iron

If you want to know the condition of insulation in submersible motors and cables.

Iron

Excellent, thank you!!  :)

no. Thanks for info on SMU (not the university)

Great program Bill

 

Iron

Thank you Bill for the interesting week.

Iron

Electronic loads vs passive resistive loads?

Thank you for the presentation Bill

Iron

Trade secret, lots of insulation and isolation.

Iron

gwp2: Why worry of µA range when dealing with 30KV?

Iron

@gwp2, how do you get that kind of accuracy?

Iron

We custom build our own for measurements down into the fractional microamp range but we are working at 30kv

Iron

Can the SMU also measure AC impedance of AC lines?

Iron

SMU's are what I use here at work.

Iron

Measuring RMS and DVM bandwidth?

what kind of clip on current meter can we use that is capable of measuring to the microamps for main line?

Iron

@gordonmx, I have experience from years ago holding the smoking end of a scope probe clip!

Iron

Scope can have grounding problems

Iron

power consumption, power dissipation, PF, Total Power, peaks power, average power, etc...

Iron

Battery power consumption

Iron

Total, including variability, peaks, mean, deviation to 3 sigma

Iron

Need to know what you are measuring and the rating of the test equipment.  In my area we measure milliamps at low voaltage to 100's of amps at medium voltages ( 1- 6 Kv)

 

Iron

RMS. Clean Power.

 

Iron

Usually real power, but I also look at Power Factor

Iron

It depends on what I want

Iron

Generally the average for power consumption for batteries

Iron

Average and Peak

Silver

power comsumption profile is interesting for my projects. Battery power management is going to be important for success.

Iron

Generally battery applications

Iron

Second question: What are you actually trying to determine about the power? average, peak, minimum, something else?

Blogger

grs311: try re-loading the page

Blogger

Sorry, forgot to say Hello from Melville, NY

Iron

audio is good here. reload page, press Play on player.

no ac power measurements for current projects.

Iron

Used scope and power analyzer.

Iron

Not very pure sine. Scope

Iron

I was hoping these courses would teach SNR, THD, etc... for power measurements.

Iron

Measuring grid 60 Hz nice sine

Iron

NO AC Line Measurements.

 

Iron

Not a very nice sinewave. It has skews as shown on the oscilloscope display. Supposed to be 400Hz, 115VAC.

Iron

Generally good with a few harmonics

Iron

@sophie   Do you have your snow gloves and moon boots at the ready?  Brrrrr...   :)

Hello from Massachusetts

Iron

Well, I useually just look at the sine wave with a scope. I could do harmonic analisys if I need to.

Iron

No, no sound yet.

Blogger

the box has not appeared yet for audio

Iron

Hi, has this session started yet?

Iron

I know, that was two questions.

Blogger

In case you want to get a head start, here's the first question of the day: For those doing AC-line related measurements, how "sine-like" is your AC signal? And how do you know this?

Blogger

Hello From Minneapolis, any sound yet?

Iron

Hello from Holladay UT - partly cloudy 37

 

 

Iron

hello from sunny MIAMI. Only three inches of rain (liquid sunshine) today.

Good afternoon folks.

Iron

Hello from Milwaukee

Iron

Reminder: download slides from link above.

Blogger

Hi from Midland TX

Iron

Thanks to all of you who have made it thru to our final session.--Bill

Blogger

Hello from Missouri

Iron

TGIF from Sunny Boston

Iron

Hello from Hemet, CA

Iron
Hello from Mesquite, NV.
Iron

Howdy folks, from SW Mo.   :)

Hello from Huntsville, Sandy (the storm) is coming in the clouds are getting heavy.  Great info this week.

Iron

Hello from Corona California, clear blue sky 73 degrees, no wind.

Hopeing for a tee shirt.

Iron

Anybody else headed to Pack Expo next week?

Blogger

Howdy folks. We're in the home stretch. Part V today. Download the presentation from the link above.

Blogger

Good afternoon, everyone

Iron

Hello from PA...waiting for the "Perfect Storm" to hit this weekend!

Hello from Baton Rouge...waiting for the big cold front to blow in. Hope the audio works better today.

Iron

Good info presented this week; thanks!

 

Hello from Sunny San Jose, CA

It's 54°F now with a High of 72°.

"GO GIANTS"

WS - SF Giants (2);  Det Tigers (0)

Iron

Hi from Colorado!  Anyone also getting a headstart today?

Iron


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