Running 380V 3-phase motor on 230V 1-phase

[Robert Atkinson 2Participant @robertatkinson2]

Oh, I’m happy to admit when I’m wrong (done it at least once in this thread). I’ll accept opposing views and statements when they are correct. One unsubstantiated example does not make it correct. The thing I can’t understand is why some proponents of the Steinmetz type of connection have to bring it up in any thread that mentions a VFD and why some of them seem so anti VFD.

Anyway OP is sorted, mystery solved.

Robert.

[jimalm]

On jimalm Said:

Mystery solved!

Today we took the motor to a motor-rewinding shop about an hour and a half drive from here and they quickly confirmed that the motor has been professionally rewound to run on 380V 3-phase mains. All the confusion arises because the person who rewound the motor neglected to replace the original 220V nameplate!

Although the motor runs beautifully on 400V, they confirmed it will be far cheaper to replace the motor (with 220V 3-phase) than to change the mains supply in my workshop. Of course I will get a VFD to provide the variable speed.

Once again, I really appreciate everyone’s contributions to solving my puzzle! Thank you all!!

Jim

Good! I wonder how much it was to get a three-speed motor rewound? It must have been a close-run thing between that and a simple step-down transformer.

[Bob Worsley]

On Bob Worsley Said:

I quite agree. Anyone with a similar problem will get no help from this thread, which isn’t, as far as I am aware, the idea of the forum, spreading knowledge etc etc?

 

This isn’t the first time. There are a couple of “experts” on here who in spite of compelling evidence will not accept a contradictory view. Their opinion is fact as far as they are concerned. Best ignored.

The old forum had an “ignore member” feature which was very useful at filtering out unwanted comments. It’s a shame it’s missing now.

[Robert Atkinson 2Participant @robertatkinson2]

Vic,

Just how is that supposed to be helpful?

Robert.

[Vic]

On Vic Said:

On Bob Worsley Said:

I quite agree. Anyone with a similar problem will get no help from this thread, which isn’t, as far as I am aware, the idea of the forum, spreading knowledge etc etc?

 

This isn’t the first time. There are a couple of “experts” on here who in spite of compelling evidence will not accept a contradictory view. Their opinion is fact as far as they are concerned. Best ignored.

The old forum had an “ignore member” feature which was very useful at filtering out unwanted comments. It’s a shame it’s missing now.

But you are one of the group who believes Steinmetz is perfect,  and chosen to ignore compelling evidence offered by others, and offered an opinion based on an “as I remember it” recollection of Workshop Practice No 16, “Electric Motors”, by Jim Cox.  I recommend the book, but get the 2nd Edition.  I’ve also read it Vic.

Jim gives a sensible overview of Steinmetz, including the warts: it’s a balanced view – Mr Cox isn’t a fanboy.

Section 3.1 covers Static Converters, and readers should study the disadvantages it identifies.  These are identified in this topic by the members who upset Bob, Andrew and yourself.  Also in the literature, and described on the web. The evidence is plain – Steinmetz  does not work “perfectly well”, and it’s notba panacea.  As there are alternatives, it pays to consider them.  Especially so in Jim’s case, where it appears he has a 3-speed Dahlender motor.

Unfortunately, those who jumped to the conclusion that Steinmetz is “the answer”, have failed to answer the objections, or, and this is the killer, provided any practical information that would help Jim. Instead, time has been wasted defending just one one of several options, without adding any technical facts;  engineering is all about problem solving,  not an ego trip, or an opportunity to bash “experts”.

Dave

 

[John HaineParticipant @johnhaine32865]

PLEASE could a mod just lock this thread? It’s no longer of any interest.

[John Haine]

On John Haine Said:

PLEASE could a mod just lock this thread? It’s no longer of any interest.

I’m not against locking it.  May have wandered beyond what’s allowed by the Code of Conduct, though hard to justify a claim that it’s been hijacked or wilfully destroyed. Also of concern that the Steinmetz debate has been unhelpfully spilled into other Topics.

The CoCo clause is:

Hijacking and wilfully destroying threads. The forum’s a big place and thread titles and descriptions are there to help you filter what you’re interested in, so please let more serious threads run broadly on topic.

Won’t lock it myself because moderators shouldn’t use their powers to censor members they happen to disagree with.  I wouldn’t complain if Jason and Neil locked it.

And of course, no-one is obliged to read it!

The Topic hasn’t been a complete waste of time.   Workshop Practical Series No 16 is identified as a good starting reference…

Dave

 

[SillyOldDuffer]

On SillyOldDuffer Said:

….And of course, no-one is obliged to read it!

Exactly! Personally I wouldn’t lock the thread; there is some useful information in it.

I was only vaguely aware of three speed induction motors, so the thread encouraged me to go away and read up on them. Likewise I was only vaguely aware of Steinmetz so read up about him too. I think it would be safe to say he was a genius despite some serious health issues.

He pioneered the concept of phasor analysis for AC circuits, using ‘j’ to represent a 90 degree phase shift, and replacing a cumbersome process of calculus. He also developed the single phase representation of a multi-phase induction motor that is useful for steady state analysis of the motor. Plus work on filters AC transmission theory and lightning.

As regards the Steinmetz circuit it clearly works and has it’s place, but is not perfect and is not fully equivalent to running a motor on a 3-phase supply.

I have ordered a biography of Steinmetz, which should be an interesting read.

Julie

[not done it yetParticipant @notdoneityet]

On the subject of the ‘hijacking’ attempt to lock the thread – I personally think all threads should be locked at some arbitrary time after the last post on the thread.

Reference to a long ‘dead’ thread is perfectly adequate/acceptable and far better than additions to it, umpteen years later.  Those extended threads are usually just a PITA, IMO.  End of further hijack.

[Julie Ann]

On Julie Ann Said:

On SillyOldDuffer Said:

….And of course, no-one is obliged to read it!

Exactly! Personally I wouldn’t lock the thread; there is some useful information in it.

Locking the thread doesn’t stop anyone reading it. As some have said, some threads drag on too long and this one seems to have touched a few nerves.

[Author]

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