VFD Article in May issue 351

[Robert Atkinson 2Participant @robertatkinson2]

I’ve Just got around to reading the May issue (351) and the article on setting up a variable speed motor drive. There a couple of issues with this article. First and not a big issue is that it is a pit of an advert for Transwave. I does say it is written by Joe Jordan of Transwave. It would be interesting to know if they were paid for the article or was it sponsered by Transwave.

More impoertant is the lack of electrical safty information. These VFDs need to be in an enclosure. They are components, not finished products. The end of the article says “only undertake work if you are competent to do so.” This is a bit pointless as a competent person would not need the article…
Transwave have prominant wording on their website saying “WE MANUFACTURE AND SELL CE MARKED PRODUCTS COMPLIANT WITH EMC REGULATIONS, THE LOW VOLTAGE DIRECTIVE AND BS EN ISO 61000-3-2:2006” One problem with this is that BS 61000-3-2 only deals with current harmonics but at least it applies to domestic installations. The version quoted is out of date, the current version is BS EN IEC 61000-3-2:2019+A2:2024.
The IMO SD1 VFD featured in the article has a CE mark but it should not have one because it is a component. The only standard mentioned in the manual for the SD1 is EN 61800-3 (no version stated) which is for inverter drives. It has 3 categories (C1-C3) applicable to 240V / 415V equipment. Only C1 is applicable to domestic premises (or commercial with domestic on the same mains feed). Unfortunatly as supplied the SD1 does not meet EMC for any category. You need an optional EMC input filter for C2 or C3. It can’t meet C1 with the IMO optional input filter alone. So the arrangement desctibed in the article is not compliant with the EMC or Low Voltage Directives and is thus illegal.

And to top it off they have a picture of really poorly made off control wiring at the termnal blocks. There should not be that much copper exposed.

IIt really makes you wonder what they are thinking….

Robert

 

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, pretty poor example of connecting  wires to terminal blocks, and the Com one with the green and other wire in, is very bad. You wouldn’t think a well known outlet would show such poor workmanship.

Regards Nick.

[noel shelleyParticipant @noelshelley55608]

Some speak of the benefits of industrial technology coming into Model Engineering and hobby, but all to often as in this case it requires knowledge and more than the basic box of tricks to work satisfactorily. With often little used equipment from universities and colleges being available, usually 3Ph, for the average model engineer the electrical knowledge is lacking. Star to Delta and 220v or 415v, contactors and their coil voltages, forwards or reverse, inverters, converters Etc, the various questions on here illustrate the point. As Robert has shown, the CE mark is often meaning less. I have used a single phase Myford S7 for over 50 years, I have never suffered from any problem that was caused by the motor or power supply. Why would I want to use a VFD, ( I have a mitsubishi unit and Delta motor but have better things to do with my time than to do a job with little benefit )

Thankfully we don’t hear of electrocutions, MCBs and RCDs must work. Noel.

[halfnutParticipant @halfnut]

And there are two different CE marks that are confusingly similar. “Conformity European” and “Chinese Export”.

The latter is illustrated on the right below, and is not worth a cracker. It means nothing. But is deliberately deceptively similar to the real EU certification on the left. That may be how some dodgy components appear to be “CE” stamped.

[Robert Atkinson 2Participant @robertatkinson2]

There is no such thing as Chinese Export mark. Just non-compliant CE marks. Technically a non-compliant mark renders the whole item illegal. Some trading standards have used this to seize items without having to pay for an expensive technical evaluation. See https://cemarking.net/chinese-export/

There are lots of advantages to fitting a 3 phase motor and VFD to a S7 or similar lathe. Even wihout using variable speed you get smoother running and better finish.

Robert.

[Robert Atkinson 2]

On Robert Atkinson 2 Said:

There is no such thing as Chinese Export mark. Just non-compliant CE marks. Technically a non-compliant mark renders the whole item illegal. Some trading standards have used this to seize items without having to pay for an expensive technical evaluation. See https://cemarking.net/chinese-export/

 

Confirms what I said: “not worth a cracker”.

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