Running a 4 kW motor

[SimonH2]

because how you wire a motor - to which ends of which windings you connect which wires from your supply does nothing to change the voltage of the supply. To be sure you may change the voltage seen across each winding by having them in series, but to my mind the operating voltage of the motor has not changed - it is still connected to a, e.g., 400V 3-phase supply.

And still you fail to understand. Rewiring the internals of the motor does not alter the characteristics of any specific supply - but it DOES alter the characteristics of supplies the motor is designed/able to run from.

Let me give you a nice simple analogy, perhaps that might help you see the gap in your understanding.

Lets say you have two incandescent light bulbs rated at 120V 50W, wire them in series, and lets say all this is inside a box* with two terminals on the outside - which you connect to a 240V supply. With me so far ? Would you now agree that the "box" is now effectively a 240V light rated at 100W ? So it's designed operating voltage is 240V ?
Would you also agree that if you connect it to a 120V supply then it won't give a very good light output ?

Now disconnect the box from the supply, open it up, and re-wire the lamps in parallel, and close it up again. Is it still a 240V ? Will it still work on a 240V supply ? No, I think we'd both agree that it's now a 120V light and connecting it to 240V would rapidly let the magic smoke out.

Now, can you see the analogy of how a 3 phase motor designed for 415 V would also be either 680V OR 230V if it's internals were re-connected ? As far as I can make out, your argument is that if you take a 415V (delta) motor and reconnect it in star - then it'll still "operate" at 415V because the supply hasn't changed.
The point is that it won't "operate" off 415V (at least, not for long) - but it would now operate off 230V perfectly satisfactorily, something it wouldn't have done while configured for 415V. Moreover, the new designed operating voltage is 230V. So even if there were no 230V 3 phase supplies used anywhere in the world, there could well be 230V 3 phase motors available simply because there isn't inherently any such thing as a single voltage 3 phase motor**.


Though looking back I do wonder if you had in mind a different idea of what "operating voltage" means ?
Oxford English : The voltage at which an electrical component or device is designed to operate or at which it normally operates.
OpenEI : The voltage level by which an electrical system is designated and to which certain operating characteristics of the system are related; also, the effective (root-mean-square) potential difference between any two conductors or between a conductor and the ground. The actual voltage of the circuit may vary somewhat above or below this value.

* And before you start getting pedantic, yes lets ensure there's a hole or window in the box to let the light out

** At least as long as we're talking about "commodity" induction motors.


And since you complained about the thread having gone off on a tangent without answering any of the questions you asked, lets look back through the thread :

Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?
That's a single-phase voltage of 133V - I've never heard of a country with that.

OK, this one is pointing out that the motors do exist regardless of whether you think they should.

I'd imaging the OP doesn't really care where.
The point is that 230/400 motors are available and 230-3phase can be generated by an inverter

I think the US has something like that, 220 or so as 3 phase, 110 single.

Confirmation that lots of motors are 230/415 dual voltage, and another statement of where you'll find such a supply

Most small industrial motors are usually wound for 230 delta, 400 star.
Japan use 200V 3 phase, either 50 or 60Hz, depending on which part of the country you're in. Must use a lot of copper...

Currently working on a project destined for use in both Japan and USA, and have managed to buy a three phase motor wound such that it will work on all voltages and frequencies, connected in delta in Japan and star in USA.

At which point you show that you still don't believe what people are telling you - it's the only inference from such a question.

Were they only ever made after inverters which produce 230V 3-phase came into being?

Some parts of Europe apparently: http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=88103
Also explains why double pole MCBs are rather more common there.

So having been told that such supplies are in fact available, you now move the goalposts because you can't see why anyone would bother.

Sorry, but what that thread tells me is that 133/230 is very rare and getting rarer. I cannot see how there would ever have been a big enough market for 230V 3P motors for manufacturers to bother, or if they once did, why they are still.

I'm not in the motor manufacturing business, but I can assume that those that are are making suitable motors because there is a market for them. And they certainly are not purely of use in the "magic box for single phase supplies" era.

In the US there is apparently a few different 3 phase ratings, but 230ish seems to be quite common. I’d imagine that would be a big enough market for them. Particularly as they are for the smaller stuff.

I'm sure they could.
I was (and still am) surprised to find that 133/230V is widespread enough worldwide for motors to have been made for it, and then later single to 3-phase converters made to mimic it. In all my years of specifying cables, PDUs, power supplies etc for IT equipment for installation in all sorts of countries it was not a voltage I ever came across.

So here we come to the "I've never seen it, so it doesn't exist" attitude I mentioned earlier. By this point you have been told that such motors do exist and did exist before the "magic boxes", AND such supplies are still in use even if they are less common than they used to be.
But you seem unable to accept that :

And it still does not address my struggle about how many people, and where, could take a 3-phase motor designed for a P-P voltage of 230 and successfully connect it to a public 3-phase supply.

So you've asked a question and had it answered; asked a different version of it and had it answered; had things explained to you so that you could understand why "230V 3 phase supply" isn't the only market for a 230V/415V 3 phase motor; had your misunderstandings of 3 phase electricity corrected; and yet still everyone else is in the wrong

 

[ban-all-sheds]

It was one of your many questions (rhetorical and/or socratic) which does, indeed, imply a suggestion. If you had (somewhat more characteristically) written something like ".... what on earth do you connect between to get 220V single-phase?" that would have been even more obvious. The implication of your question was surely that you did not believe that one could get 220V by 'connecting between' anything?

Please do not try to present a flawed inference drawn by you as an implication made by me.

 

[JohnW2]

Please do not try to present a flawed inference drawn by you as an implication made by me.

Why did you ask the question (if not to make an implication)? - Presumably not because you were unable to work out the answer for yourself.

Kind Regards, John

 

[ban-all-sheds]

And still you fail to understand....

And still you fail to understand.

At no point have I denied that motors can be made to run on a variety of supplies.

Telling me over again that they can be is pointless - I know they can, and am not denying it.

My question was, when told that a motor could run off of a 230V 3-phase supply, where do you get 230V 3-phase supplies.

Asking where they are available is not an assertion that there are none. It is a question asking where they are.

Rewiring the internals of the motor does not alter the characteristics of any specific supply - but it DOES alter the characteristics of supplies the motor is designed/able to run from.

Indeed it does.

I'm sure a motor could be made which could be wired to work off a 73V 6-phase supply. But doing so would not magically create 73V 6-phase supplies for people to connect it to.

Let me give you a nice simple analogy, perhaps that might help you see the gap in your understanding.

Lets say you have two incandescent light bulbs rated at 120V 50W, wire them in series, and lets say all this is inside a box with two terminals on the outside - which you connect to a 240V supply. With me so far ? Now - you could open it up and re-wire the lamps in parallel, so that it would work on a 120V supply. Something which would be of no use to anybody if they could not obtain a 120V supply

Now, can you see the analogy of how a 3 phase motor designed for 415 V would also be either 680V OR 230V if it's internals were re-connected, but that would be of no use to anybody if they could not obtain either 680V or 230V to supply it with.

As far as I can make out, your argument is that if you take a 415V (delta) motor and reconnect it in star - then it'll still "operate" at 415V because the supply hasn't changed.
The point is that it won't "operate" off 415V (at least, not for long)

Long enough for it to start.

but it would now operate off 230V perfectly satisfactorily, something it wouldn't have done while configured for 415V.

Indeed.

If you could provide it with 230V.

Moreover, the new designed operating voltage is 230V. So even if there were no 230V 3 phase supplies used anywhere in the world, there could well be 230V 3 phase motors available simply because there isn't inherently any such thing as a single voltage 3 phase motor.

And the point of designing a motor to work with a supply which no customer could obtain would be what, exactly?

Though looking back I do wonder if you had in mind a different idea of what "operating voltage" means ?
[LINKHL]4131[/LINKHL] : The voltage at which an electrical component or device is designed to operate or at which it normally operates.

That seems a reasonable definition.

And if you alter how a motor is wired you may alter its operating voltage (or you may not, if you've only temporarily rewired it for starting, and are still giving it the same voltage).

My point was that rewiring a motor to operate off a different voltage does not magically make that voltage available to the motor.

And since you complained about the thread having gone off on a tangent without answering any of the questions you asked, lets look back through the thread

OK, this one is pointing out that the motors do exist regardless of whether you think they should.:

I'd imaging the OP doesn't really care where.
The point is that 230/400 motors are available and 230-3phase can be generated by an inverter

Can you show me where I have expressed the view that I don't think they should exist?

Can you show me where I disputed what Jackrae told me?

Or are you just so determined to pick a fight that no matter what questions I ask you will deliberately pretend I have asked, or asserted, something I have not written, and then on finding you don't like what you have invented decide to blame me for it?

Confirmation that lots of motors are 230/415 dual voltage, and another statement of where you'll find such a supply

Most small industrial motors are usually wound for 230 delta, 400 star.

Those voltages make sense - if you reconnect a 230V motor from delta to star then you can use it on a 400V supply.

But that does not answer my question about where there would be a 230V 3-phase supply to use it on.

Japan use 200V 3 phase

200V is not 230V. I thought that a 13% under-voltage was too much?

At which point you show that you still don't believe what people are telling you - it's the only inference from such a question.

The point is that 230/400 motors are available

Were they only ever made after inverters which produce 230V 3-phase came into being?

It is not the "only inference".

Firstly, no "inference" needs to be drawn from, and no implication was being made by, "Were they only ever made after inverters which produce 230V 3-phase came into being?".

What you could do, on reading that, is to just read it as written, i.e. a question which means what it says, says what it means, and nothing else.

Secondly, are you just so determined to pick a fight that no matter what questions I ask you will deliberately decide to "infer" that I have asked, or asserted, something I have not written, and then on finding you don't like what you have inferred decide to blame me for it?

 

[ban-all-sheds]

So having been told that such supplies are in fact available, you now move the goalposts because you can't see why anyone would bother.

I've not moved any goalposts.

Shall we look again at my original question?

Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?

And at the number of times I repeated it?

"Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?"

"Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?"

Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?
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"Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?"
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"Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?"
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"Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?"
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"Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?"
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Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?

You think you can accuse me of moving the goalposts when what you are doing is completely ignoring the second part of that question?

You reference this:

Some parts of Europe apparently: [LINKHL]4121[/LINKHL]

Sorry, but what that thread tells me is that 133/230 is very rare and getting rarer. I cannot see how there would ever have been a big enough market for 230V 3P motors for manufacturers to bother, or if they once did, why they are still.

I'm afraid that topic on the IET forum, and the website(s) it references really show that 230V 3-phase supplies are rare and getting rarer.

I'm not in the motor manufacturing business, but I can assume that those that are are making suitable motors because there is a market for them. And they certainly are not purely of use in the "magic box for single phase supplies" era.

OK - you assume that. But don't then decide to have a go at people who have some curiosity and ask questions.

So here we come to the "I've never seen it, so it doesn't exist" attitude I mentioned earlier.

No, here we come to the "I've never seen it so I am surprised to learn that it is widespread enough worldwide for motors to have been made for it, and then later single to 3-phase converters made to mimic it" attitude.

Why are you so determined to pick a fight that when I wrote (in effect) "I've never seen it so I am surprised to learn" you decided to pretend that I had written "I've never seen it, so it doesn't exist"?

By this point you have been told that such motors do exist and did exist before the "magic boxes", AND such supplies are still in use even if they are less common than they used to be.
But you seem unable to accept that :

And it still does not address my struggle about how many people, and where, could take a 3-phase motor designed for a P-P voltage of 230 and successfully connect it to a public 3-phase supply.

You should go back and look at the post of yours to which that was my reply.

It really did not do anything to explain where people are going to find a 230V 3-phase supply to connect to.

So you've asked a question and had it answered; asked a different version of it and had it answered

Not really.

had things explained to you so that you could understand why "230V 3 phase supply" isn't the only market for a 230V/415V 3 phase motor

So what is the use of the 230V capability of such a motor in the absence of a 230V supply to connect it to?

had your misunderstandings of 3 phase electricity corrected

Are you really so determined to pick a fight that you're prepared to misrepresent an arithmetic mistake as a misunderstanding of 3 phase electricity?

 

[ban-all-sheds]

Why did you ask the question (if not to make an implication)? - Presumably not because you were unable to work out the answer for yourself.

I explained why:

One which I asked Simon to confirm that when he uses the term "X volts 3-phase" he does mean the voltage between phases, because there was a time, earlier on, when I wondered if sometimes he meant something else

Are you so determined to pick a fight that you're prepared to ignore what I say, insist that I was implying something I was not, and then, on finding you don't like the implication which is entirely in your mind, criticise me for it?

 

[JohnW2]

I explained why: ..............................

I have nothing new to add.

Kind Regards, John

 

[SimonH2]

And still you fail to understand.

At no point have I denied that motors can be made to run on a variety of supplies.

Telling me over again that they can be is pointless - I know they can, and am not denying it.

Yes, but you specifically asked (several times) WHY WOULD ANYONE BOTHER.

Sorry, but what that thread tells me is that 133/230 is very rare and getting rarer. I cannot see how there would ever have been a big enough market for 230V 3P motors for manufacturers to bother, or if they once did, why they are still.

So what is the use of the 230V capability of such a motor in the absence of a 230V supply to connect it to?

The point I was making, and which you seem determined to not see, is that there doesn't need to be a large market because making a motor to run on 230V 3 phase may be just a different connection for a motor that is designed primarily for another market. And as pointed out well before you stopped asking where, such a supply is found in many parts of the world. The fact that they may be getting rare doesn't alter the fact that they do exist, and they did exist a long time ago - so there was a market for the manufacturers to service.

I'm not "picking a fight", I'm merely trying to educate someone who it seems is determined not to learn.

And that's all I have to say on your diatribes.

 

[ban-all-sheds]

I have nothing new to add.

Including not an apology.

You had nothing truthful (and therefore useful) to say about why I asked Simon the question I did - shame your reticence couldn't have struck earlier.

 

[JohnW2]

.......

I have nothing new to add.

Kind Regards, John

 

[ban-all-sheds]

Yes, but you specifically asked (several times) WHY WOULD ANYONE BOTHER.

I did. Although in the majority of those cases it was because I was having to point out that that is what I had asked to people who thought that the words ""Where in the world do they have 230V 3-phase supplies, such that there would be motors made for it?" actually mean "Nowhere has a 230V 3-phase supply, so there would not be motors made for it".

And as pointed out well before you stopped asking where, such a supply is found in many parts of the world.

Honduras, Kosovo, Norway, Trinidad & Tobago.

And from another source you cited, only in "some" places in Norway.

The fact that they may be getting rare doesn't alter the fact that they do exist

I've never claimed otherwise.

, and they did exist a long time ago - so there was a market for the manufacturers to service.

That was something which puzzled me, which was why I asked. Is there a large enough market with 3-phase 230V supplies?

Sadly, simply asking that question seems to have incensed some people here.

I'm not "picking a fight", I'm merely trying to educate someone who it seems is determined not to learn.

If I am determined not to learn, why did I ask my question in the first place? Why did I ask you "what is the use of the 230V capability of such a motor in the absence of a 230V supply to connect it to?" when you said "230V 3 phase supply isn't the only market for a 230V/415V 3 phase motor"?

And if you are not trying to pick a fight, why do you keep on accusing me of things which are untrue?

And that's all I have to say on your diatribes.

Oh, I see.

So it's OK for you to write a post containing several false allegations, but when I point out that they are false that's a forceful and bitter verbal attack, a tirade, a stream of abuse.

 

[ban-all-sheds]

I have nothing new to add.

Well - the next time you feel that way, please do us all a favour and add nothing, rather than add something containing false allegations.

 

[JohnW2]

Well - the next time you feel that way, please do us all a favour and add nothing, rather than add something containing false allegations.

I am adding nothing.

I have nothing new to add.

Kind Regards, John

 

[ban-all-sheds]

You seem to recognise that now.

You should have recognised it before you wrote this:

Why did you ask the question (if not to make an implication)? - Presumably not because you were unable to work out the answer for yourself.

 

[JohnW2]

You should have recognised it before you wrote this: .....

I have nothing new to add.

Kind Regards, John