3-phase: a thought-provoking recondite conundrum

hi all,
I finally got my 3 phase lathe working off a phase converter and as some of you warned me, the motor initially turned in the wrong direction. Now I know all I have to do to correct this is swap two phases, but the que stion I want answered now is, could I have avoided this extra task if I'd a ssumed from the outset that a swap would be needed and just done it before even switching the thing on for the first time?
cheers.
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On 11/08/2013 15:08, snipped-for-privacy@virgin.net wrote:

IME, if you do that, it is the only occasion it would have gone in the right direction first time.
Colin Bignell
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On Sunday, 11 August 2013 16:43:09 UTC+2, Nightjar wrote:

e of you warned me, the motor initially turned in the wrong direction.

question I want answered now is, could I have avoided this extra task if I 'd assumed from the outset that a swap would be needed and just done it bef ore even switching the thing on for the first time?

Right, so the best advice is to swap the wires over immediately before test ing the motor for the first time; thanks.
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On 11/08/2013 15:43, Nightjar wrote:

It does make you wonder, how many 3ph supplies actually have the phases correctly identified... you would think that keeping L1 matching L1 and so on through the installation you should get something better than 50% right first time!
--
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John.
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On Sunday, 11 August 2013 17:13:44 UTC+2, John Rumm wrote:

Well, quite. The supply cable that came with this 3-phase welder I bought had all 3 phases colour coded the same shade of brown. Not sure what year that scheme became impermissible!
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"John Rumm" wrote in message wrote:

Well as I supervised the installation of my 3 phase incomers, and wired all my (extensive) three phase installation myself I can with confidence select L1, L2 & L3 in any of my five buildings and KNOW that they are correct. I also use a phase rotation tester each and every time I install a three phase socket. (which seems to be a fairly frequent occurrence of late)
AWEM
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On 11/08/2013 18:04, Andrew Mawson wrote:

A sign of a man with too many new toys ;-)
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John.
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On Sun, 11 Aug 2013 19:34:31 +0100, John Rumm

Is such a thing possible?
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On 12/08/2013 02:23, Grimly Curmudgeon wrote:

On reflection, probably not ;-))
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"John Rumm" wrote in message wrote:

Well it's got to the stage where more and more is going back on ebay just to create a bit of elbow room ..... <G>
AWEM
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On 12/08/2013 12:54, Andrew Mawson wrote:

If its going back at more than purchase price, then its not a bad thing...
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snipped-for-privacy@virgin.net wrote:

If you are using a converter (as distinct from an inverter) It is worth making sure that the switchgear contactors are not supplied from the artificial phase but direct from the internal auto transformer. This is because the voltage on the artificial phase can be all over the place especially during motor starting and the last thing you want is the contactor dropping out when you start up.
DAMHIKT!
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On Sunday, 11 August 2013 17:18:23 UTC+2, Bob Minchin wrote:

e of you warned me, the motor initially turned in the wrong direction.

question I want answered now is, could I have avoided this extra task if I 'd assumed from the outset that a swap would be needed and just done it bef ore even switching the thing on for the first time?

Not entirely sure what you're on about here, Bob, but I'm using a *static* converter: 230V single phase in; 230V three phase out.
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wrote in message wrote:

Covered that several posts ago, but pearls before swine I think . . . . . . . .
AWEM
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wrote:

Not entirely sure what you're on about here, Bob, but I'm using a *static* converter: 230V single phase in; 230V three phase out.
Most of them rectify the AC 1 phase and then generate the 3ph "from scratch"
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harryagain wrote:

Bollocks Harry - you are talking about an INVERTER not a converter. A world of difference
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On 11/08/2013 15:08, snipped-for-privacy@virgin.net wrote:

Not according the Murphy.
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hi all,
I finally got my 3 phase lathe working off a phase converter and as some of you warned me, the motor initially turned in the wrong direction. Now I know all I have to do to correct this is swap two phases, but the question I want answered now is, could I have avoided this extra task if I'd assumed from the outset that a swap would be needed and just done it before even switching the thing on for the first time?
There is an expensive instrument that will indicate phase rotation. No-one buys them because it's easy to perform the experiment with a 50/50 chance of first time success. Few things are damaged by going backwards. As you clearly don't have any luck, do not buy any lottery tickets. :-)
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On Sun, 11 Aug 2013 07:08:57 -0700 (PDT), snipped-for-privacy@virgin.net wrote:

You could have avoided it by using an inverter and just changing the labels on the forward and reverse buttons.
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