Measuring and Seeing Output of High and Low Frequency Inverters with Scope Meter

[Hillseeker]

Will your work is the best, I really respect you and your work.
We work with Variable Frequency Drives to control the speed of AC motors for industry and HVAC systems.
We use Fluke Scope Meters that prove to be an excellent tool for seeing the output of inverters.
I don't know if you have tried this. We can tell the "health" of the VFD by looking at the output waveform during maintenance.
It is great to be able to see the output voltage compared to the true sinusoidal input of the AC source.
I am sure you would really like adding this to your break down tests of new products.
The shape of the output waveform derived from turning the IGBTs or Fets on and off supper fast to simulate an ac waveform.
Over the 40 + years of servicing electronic motor controls I found 20 years ago the scope meter to be the most valuable tool that lets you see what inverter is putting out. As components start failing you can see the waveform start to deteriorate and loose definition.
It would be a great addition to your tests, full loads and load surges can be compared product to product.
I think you will geek out on it like I have over the years.
I don't know if you have a scope or not. It is great to be able to see the voltage and current sinewaves.
I would like to see difference between the high and low frequency inverters.
We have used the Fluke 43B not made anymore but can be found for less than $1K used.
Let me know your feedback.
Thanks for all you do Will
Pete

 

[efficientPV]

Any lawyer will tell you to never ask a question if you don't already know the answer to it. The same goes for using test equipment. You should know what to expect. I've seen a lot of scope pictures here that wouldn't make any sense unless you understood the electronics behind them. These scope traces were all due to improperly connecting the scope. Aside from what they were doing was dangerous, what they as an issue was totally normal.

Very beginner scopes today, as low as $50, are well beyond what I could have ever dreamed of when I started out in electronics. These scopes have so many capabilities that the multiple vast menu selections will overwhelm the beginner. I've seen videos of screens where the person was asking us to make sense of. It was nothing but garbage.

 

[Goboatingnow]

I held on to my fluke 43B , I have it in the boat. Useful.

 

[sirslayer]

I work with VFDs and usually they have remote access that you can monitor voltage, current , etc etc and setup alarms. Usually if the vfd goes down , it’s a simple replace and remove . Throw the bad vfd with the rest of the pile .. most of the time the warranty have past .. we don’t plan to repair them

 

[teal95]

Yes, it's amazing what a $50 oscope that looks like a cell phone can do compared to state of the art when I was in college. (I can remember my first circuit class our "datalogging" was a Polaroid that clipped onto the oscope.)

 

[efficientPV]

I just bought the cheapest stand alone scope $200 that had a math multiply function so I could test solar panels. I did have just a USB scope and I loved it, it had math, because everything was just an easy mouse click. This new one is a little irritating. With more features it is an endless selection of menus, pressing buttons and small type I can't read.