VFC on a multmeter - Page 1
Forum section: electronics / testgear

author: Butch
author_rank: Newbie
timestamp: April 08, 2020, 07:27:08 pm
content: Hi,The other day i bought a multimeter (Mustek DMC100c) that has a V.F.C function (Voltage Frequency Converter).From the manual i can not really understand what this function adds to the multimer and what the benefit is.Can somebody explain this function (in theory and what the benefit is to the accuracy of an AC-measurement)?RegardsButch

author: ogden
author_rank: Super Contributor
timestamp: April 08, 2020, 08:37:51 pm
content: Voltage to frequency converter most likely is internal function of said obscure multimeter that adds nothing to function or accuracy of said device. Seems like marketing BS. Note that google search returns exactly zero hits for "Mustek DMC100c".

author: Butch
author_rank: Newbie
timestamp: April 08, 2020, 09:47:38 pm
content: Thanks for the response.How does this answer my question? "most likely", "obscure", "Seems", "No google return".Regards

author: bob91343
author_rank: Super Contributor
timestamp: April 08, 2020, 10:02:40 pm
content: If indeed the acronym means Voltage to Frequency Converter, I don't see its application for a voltmeter. If it were Frequency to Voltage, then I'd guess it would turn it into a frequency meter.Searches on the brand name and on the model number bring up nothing useful.What do you get when you select vfc? What is the info in the manual?

author: 2N3055
author_rank: Super Contributor
timestamp: April 08, 2020, 10:03:00 pm
content: That is probably filter to filter out high frequencies when measuring VFC (frequency converter motor controllers) that use high frequency PWM. And it is Mestek ..

author: ogden
author_rank: Super Contributor
timestamp: April 08, 2020, 10:24:33 pm
content: Quote from: Butch on April 08, 2020, 09:47:38 pmAnswer to your question was: "adds nothing to function or accuracy of said device"Quote from: 2N3055 on April 08, 2020, 10:03:00 pmSeems you (OP) can't even properly tell what you are talking about.

author: 2N3055
author_rank: Super Contributor
timestamp: April 08, 2020, 10:45:07 pm
content: Quote from: ogden on April 08, 2020, 10:24:33 pmIt is Mestek DMC100c not Mustek. It is obvious what I meant. (BTW Mustek makes scanners)..And what you said was wrong. A low-pass filter for measurement of voltage on motors connected to frequency converters is a common function and I'we seen it called VFD and VFC on metes. For instance, Extech calls it VFC, Bymen and Fluke VFD.It filters out PWM frequency from VFD controller and leaves only low frequency to be able to accurately measure RMS voltage/current going into motor.. It's not marketing wank and is absolutely useful if you work with motor control

author: ogden
author_rank: Super Contributor
timestamp: April 08, 2020, 11:01:34 pm
content: Quote from: 2N3055 on April 08, 2020, 10:45:07 pmI was not addressing you. Sorry if you did not get itBTW note that I clarified who I am talking to, long before your post.Quote from: 2N3055 on April 08, 2020, 10:45:07 pmThank you for explaining, in your 2nd try. Initially you were not so sure:Quote from: 2N3055 on April 08, 2020, 10:03:00 pm

author: joeqsmith
author_rank: Super Contributor
timestamp: April 09, 2020, 01:23:38 pm
content: Quote from: Butch on April 08, 2020, 07:27:08 pmWelcome to the forum. The Variable Frequency Drives (Controllers) can be a problem to measure. A while back I was playing around with a Fluke non-contact type voltage meter and was curious if it would have troubles with something more complex than AC coming into the house. I setup a test using a scope to provide a visual idea of what the waveforms I applied looked like. Testing begins with a small VFD.BTW, later I took the Fluke with me to try on some other controllers and it was hit and miss if it would work or not, mostly depending on the carrier frequency the VFD was set to.

author: Wytnucls
author_rank: Super Contributor
timestamp: April 10, 2020, 12:44:38 pm
content: Does not seem to have anything to do with voltage conversion: