240-415V step up VFDs - online bunfight!

[bikepete]

I was just thinking of buying one of these:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ih=005&item=150009545993

to power a not-easily-replaced and not-easily-rewired 415V three phase motor from (UK) 230V single phase. It's the first VFD which I'd seen which takes 240V as the input and puts out 415V.

Then did some more digging and found this:

This ebay guide

saying that this VFD was probably illegal to use. The seller then replied with this:

This other ebay guide

Saying that indeed they did have no CE mark before but they do now...

Any views? How come there aren't more people selling these 240-415 VFDs? Anyone tried one of this type?

 

[J Lauffer]

How come there aren't more people selling these 240-415 VFDs?

Probably because it requires modifying a standard unit. I don't think the market is big enough for any VFD manufacturers to bother with it.

John

 

[bikepete]

Could well be. I guess most modern motors are 240 or dual voltage so it would only be for older equipment. The 230/240 to 400/415 voltage combination should be good in most parts of the EU though.

 

[Jraef]

Undoubtedly what they have done is to build a "voltage doubler" board and install it inside of that drive. I seriously doubt that Teco did that at the factory because as J. Lauffer said, the market for it would be way too small for Teco to bother. When I dealt with them, the only thing they were interested in were lots of 10,000 or more.

When they came back saying they have CE now, I would be suspect. Most likely they took their voltage doubler board to some cheap CE testing authority who tested of their board, but most likely not the entire drive. The reason I think that is that there is NO room inside of that drive for another board, so the only thing they could have done would be to remove the EMI filter board, which would have been integral to the original CE labeling of the VFD in the first place.

If you are curious, get all the part number information on the drive and contact your local Teco office. They will tell you straight up if Teco did this custom project. If not, then something is likely amiss in their representation of having CE.

 

[bikepete]

I think Teco had no involvement - the extra board or whatever seems to be his own development. No doubt his rival at Transwave has already alerted Teco UK if they didn't know about his mods already.

Dunno if I'm that interested really. Just got a line on a suitable transformer and a 415-415 VFD at a combined cost of about a third of what he wants for that one. A less elegant solution perhaps.

 

[JST]

The amount of modification necessary to get a unit intended for 240V to work for 415V is non-trivial.

All the output switches probably need to be replaced.

Depending on how the drive is coupled to them, the drive units MAY need to be replaced.

The input requires a voltage doubler, OR a "PFC" with the necessary output voltage. The PFC would avoid "contravening" the harmonic rules.

That is if the seller actually knows what he is doing. if not, the innards may be running on the ragged edge of failure......

CE mark? It isn't difficult.... and means very little, aside from the EMI testing required.

The safety stuff has been eroded and reduced drastically, especially with the "performance testing" as opposed to a combination of required construction PLUS performance testing.

Example.... where 3mm to 6mm clearance between live parts used to be required, now it may be as little as 1.25mm. And less,even, so long as a test does not show voltage breakdown (at least on that particular test unit!).

It is now possible, and even advisable, to make units in such a way as to pass the tests, whether or not that makes them safer in "real world" usage......

Combine that with the well known chinese "attention to detail and craftsmanship" and you got a trainwreck coming....

As with the 415V units.... If modified, they probably are on the edge of unsafe.... If purpose built, might be OK, or not.....

 

[Mike Henry]

I've been told that CE is essentially a self-tested standard. I do know that it means absolutely nothing at work wrt electrical safety, where UL or one of the NRTL marks is required to avoid individual equipment inspection.

If that info on CE is correct it might not mean much for this item.

Mike

 

[Jraef]

J Tiers,
Your issues are valid if they tried to modify a 240V drive to put out 400V, but they undoubtedly started with a 400V drive and modified the front end to accept 240V on the voltage doubler, not the other way around. The drive they picture there appears to be the 400V class, so that would solve most of the issues you raised. The voltage doubler would be a cap and rectifier board that would take the 240VAC then feed about 520VDC into the line terminals of the 400V drive, which would just pass straight through the original rectifier on the VFD. That's how they do it on the 115V input / 230V output version.

Also, although I have no affiliation with Teco, I must say they are not "Chinese", they are Taiwanese (and willing to die for the difference). They have exceptional attention to detail and craftsmanship, I have nothing but respect for the quality of Teco drives. They are just not in possession of a lot of innovative spirit; they tend to let others try things out for a few years then copy it inexpensively.

I agree with Mike's statement about CE, except for a quirk of the "self testing" issue. The original manufacturer can self-certify IF they are in a member EU country, otherwise they must partner with an EU based certifying agency to test and certify. In the case of Teco, they used TUV (Netherlands) as their testing agency, but I seriously doubt Teco or anyone else would have tested the entire drive WITH the voltage doubler. That would have cost around $20,000 US, which eats into the profits of an awful lot of $250 drives. More likely the UK purveyors of the modified drive got CE on their board alone, maybe they even self-certified it, then stuffed it into the CE labeled VFD. But in doing so they would have violated the original CE labeling of the VFD.

Either way, it still looks suspicious to me.

 

[JST]

JRAEF: Not necessarily.......

I have had a LOT of products tested to CE..... All you HAVE to do is put on the mark..... it's illegal if you can't back it up, but they rarely ask....

Our agency was ETL, which is US, but owned by a holding CO that also owns the Swedish agency.

CE DOES ABSOLUTELY address safety.... There is a thick book of regs. The exact one depends on what you make.

AND, UL is history. There is no UL any more, they have accepted the EN standards.

EN60065 is the "CE" standard we at work fall under, and the UL standard is UL60065..... There are about 200 lines difference, in a thick book of stuff. Much of it is quite minor.

The old UL spacings requirements are GONE... history.

Now, if those guys started with a 400V unit, that would be sensible. I thought the next voltage was higher, and that didn't look like it...

Taiwan is a province of china..... That isn't doubted by anyone, since china has the ability to enforce that in the face of any country on earth, if they choose.

In reality, it is a sort of "Sudetenland", but who's counting?

 

[peterh5322]

"Now, if those guys started with a 400V unit, that would be sensible."

A 460 volt unit would be a good start.

A voltage doubler operated on 240 would produce about 650 volts as the dc bus voltage, although the "quality" of that voltage would be lower than with three-phase, or even single-phase input.

Still, it should be good enough for 380/400/415 volt three-phase output.


"Taiwan is a province of china..... That isn't doubted by anyone, since china has the ability to enforce that in the face of any country on earth, if they choose."

By the same reasoning, namely, "... the ability to enforce ...", Canada and Mexico are provinces of the Unites States.


Based upon number of megatons presently in inventory, and the capability to deliver these, we could easily annihilate China in about five minutes, with a low risk of any substantive retaliation, so it is doubtful that China could, as you state, "... enforce that in the face of any country on earth ..." (emphasis is mine).

The "war" to liberate Taiwan from China would be a very short one indeed.

 

[Jraef]

My point in the Taiwan/China issue was that China (communist) has a somewhat deserved reputation for low quality and poor attention to detail. With Taiwanese mfg on the other hand, the QC processes and pride of workmanship have had more time to develop and are apparent in their output (for the most part). I thought it unfair to color a Taiwanese manufacturer with the same brush as a Chinese knock-off producer. That's all.

Let's all pray that China never feels the need to "enforce" anything on Taiwan and vice-versa. The resulatnt mess would not benefit anyone on this planet.

And by the way, most Asian VFDs have only 2 voltage "classes", 200V covering everything from 200-250VAC input, and 400V which covers 380 - 480V input. So when I said they would have used a 400V drive, I meant 400V class, which would cover the higher DC bus voltage. Some EU manufacturers also have what they call a "500V" class which covers 480 - 575V, then a few also have a 690V that can accept 575-690V input. I don't see any value in going to a 500V class drive for a voltage doubler input from 240V 1 phase.

All you HAVE to do is put on the mark..... it's illegal if you can't back it up, but they rarely ask....

Well that could be said about ANY approval agency listing, and quite a few people have been caught doing that over the years. I imagine CE is no different in that respect other than maybe a lower likelihood of someone checking. My point on that was that the reseller who came back and said "we have CE now" may have been stretching the truth a bit, which is what I think you were implying as well, so let's just agree on that.

 

[peterh5322]

I recently reordered items which formerly had silk-screened indicia: manufacturer's logo, model number, components, FCC data and mark, CE mark, 94V-0 mark, raw board build date, etcetera.

All indicia on the newly built items were on stick-on labels, with the exception of the components, the 94V-0 mark and the raw board build date.

The only stick-on label in common with the two were the manufacturing date and serial number label, which was stick-on for both.

Weird.

 

[JST]

The CE mark formerly at least, could be on the unit, or on the literature, but had to be on the box.

In practice, it is on the piece, in general, as well as the box.

And, CE was unique in that it IS really self-declared. There is no EU agency that DOES the testing.

The EU enforces IF there is a proved failure to actually comply.

But you contract with a third party, some form of recognized body, or NRTL, to test. Then you STATE that your product passed, by marking it.

This is in contrast to UL, which issues a recognition label number for your product. Same with ETL, or CSA (Cul) etc.

So tehre is an EXTRA incentive to save the money and simply mark CE, hoping you will not be called on it. That does not exist with UL, which is an adder, not a requirement.

 

[JST]

The CE mark formerly at least, could be on the unit, or on the literature, but had to be on the box.

In practice, it is on the piece, in general, as well as the box.

And, CE was unique in that it IS really self-declared. There is no EU agency that DOES the testing.

The EU enforces IF there is a proved failure to actually comply. Then you have to prove you DO comply.

But you contract with a third party, some form of recognized body, or NRTL, to test. Then you STATE that your product passed, by marking it.

This is in contrast to UL, which issues a recognition label number for your product. Same with ETL, or CSA (Cul) etc.

So tehre is an EXTRA incentive to save the money and simply mark CE, hoping you will not be called on it. That does not exist with UL, which is an adder, not a requirement.

Incidentally, it is assumed in some of the CE items, notably the EMI, that about 80% of the units claimed to pass really will pass... That is 80% of examples of that unit need to pass. So a single failure is not proof of fraud, grounds for fines, etc.'

On the safety side, so far they are still a bit tougher. But still, the old rule of safety agency testing is that after their tests the unit need not still work, but it cannot create a hazardous condition.... fire, shock hazard etc.

So testing "guarantees" only that the thing is reasonably unlikely to burn your house down or kill you by shock. It deos not say the product is any good for what it allegedly does.

The 500V class was what I was thinking of......

 

[peterh5322]

Here's a schematic diagram for a 230-to-460 voltage doubler modification to a VFD.

In practice, this will not work as as shown as the original "converter" section is not designed for this service.

However, an external converter could be employed, functionally replacing the converter section of the VFD, and I would guess that the doubler-type converter/VFD mentioned earlier has essentially this topology.

In one 460 VFD which I disassembled for examination and evaluation, the "bulk storage" capacitors were in series connection, as shown below.

This made it easy to connect L2 to the capacitors, at the point of their connection to one another, for purposes of evaluating the practicality of a doubler-type converter/VFD.

In practice, much higher rated diodes, and possibly twice the total capacitance would be required.

 

[andrewmawson]

Peter,

I think I follow the jist of your circuit but not the detail - unfortunately the inserted image is just too fuzzy to make out. Is there any chance of you posting a link to a higher resolution image and also a stand alone doubler for external connection. Presumably with an external cct providing DC the existing internal diodes could just be left in place and would be rated ok ?

AWEM