Phase rotation meter ?

[Evans Electric]

Strangely I've never owned one  but just wondering .

If you were on a job with a new supply , say,   and the DNO were there  using their phase rotation meter  ..and they stated that the supply was indeed  L1...L2...L3    ( or RYB to me)  and the phase direction was clockwise ...and I then connected a small  3 ph motor  which ran clockwise,     marked the direction of spin on it .... have I made myself a  Phase Rotation Meter. ?   

 

[kerching]

Well, you have certainly made a Phase Rotation MOTOR

 

[kerching]

Can't see why not as long as it has the right protection .      

I think the best ones are thise that you connect to a dead/off supply motor, spin shaft and it tells you rotation!

screw compressors really REALLY dont like reverse polarity, they sulk and go moody in a sort of ' phuttt BANG shear/snap ' sort of way.

the better ones have a reverse rotation safety interlock

 

[Andy™]

i suppose so, but a phase rotation tester is probably a little more portable and practical than carrying around a TP motor

 

[Evans Electric]

crew compressors really REALLY dont like reverse polarity, they sulk and go moody in a sort of ' phuttt BANG shear/snap ' sort of way.

the better ones have a reverse rotation safety interlock

I know , I've always been wary of them .    The old fashioned ones ...I think ...as long as the piston goes up & down thy're fine . 

I've had people say ...for years now....  if you connect the motor L1 L2 L3    to A B C   or 123   or L to R    it will run the correct way  :C  so you should always wire in phase colours.

There are two things wrong with that ....(a)   You don't know which way the machine has to turn   & (b)    if the motor is fitted  arse about face  it'll turn the other way . 

I always mark rotation if I'm disconnecting   or request that someone does it 

Some machines appear to be OK  on re-connection  but you find..say...a lube pump runs backwards .  

 

[Tony S]

The foreman of a gang of contractors working on a new plant confidently told me every drive on the plant would run in the right direction. I hadn’t the heart to tell him the entire works was BYR, it was a hangover from the days when we had our own power stations. He wanted to swap the incoming feeds to six MCC panels. I wouldn’t let him, each drive had to be swapped at the motor.

 

[Geoff1946]

There is (or was), some difference in phase rotation conventions between Germany and UK;  

It was either the way they are labelled or measured, I can't remember details fully but it did lead to some embarrassment when we were both designing parts of the same aircraft.

Beware if dealing with imported gear. 

 

[rapparee]

The Greater Belfast area is in reverse compared to the rest of the province.

 

[Evans Electric]

The Greater Belfast area is in reverse compared to the rest of the province.

Are you saying you're a bit backward over there ?  :innocent

We must be the same as France  as , I believe , we have a power connection under the channel .  

 

[Geoff1946]

Are you saying you're a bit backward over there ?  :innocent

We must be the same as France  as , I believe , we have a power connection under the channel .  

Aren't the inter country links DC?

 

[rapparee]

Aren't the inter country links DC?

They are, he's just a bit simple, pay no attention, let him have his moment. 

I also remember being told that parts of Belfast City centre still has the DC supply in operation.

The NIE wanted to abandon it but shops didn't want to replace lift systems etc.

 

[Evans Electric]

Why would the inter country links be DC  ?   I  read that the British & French grids were connected and load sharing & shedding took  place at peak times . 

 

[rapparee]

Because they would be out of sync if they were AC.

It would be like crossing two phases.

 

[Tony S]

Why would the inter country links be DC  ?   I  read that the British & French grids were connected and load sharing & shedding took  place at peak times . 

https://en.wikipedia.org/wiki/HVDC_Cross-Channel

 

[poni]

Is it 3 wire DC ? I was told and I don't know if its true ,that they use the sea as the third wire  .

 

[Tony S]

Bipole + - 250kV DC or there abouts. Bipole is used to stop the cables interfering with ships magnetic compasses as each pair of cables cancel each other out.

Some parts of the world do use earth return for remote distribution.

https://talk.electricianforum.co.uk/knowledgebase/transformers/swer/single-wire-earth-return-r51/ 

 

[Geoff1946]

That's a really good "Wiki" link. Loads of info.  Thank you.

https://en.wikipedia.org/wiki/HVDC_Cross-Channel

 

[Tony S]

I have to say, I’ve never used a phase rotation meter. So long as the phase colours are maintained throughout the works, what does it matter?

All our plant were originally 550V BYR. All well and good until our genius engineer decided that new plants using this new fangled 433V should be RYB. I got involved when a plant was converted from 550V to 433V and it should be BYR to fit in with the existing plant.

Things went from bad to worse when I installed a new switchboard fed from two plants RYB and BYR supplies. The incoming section just looked so wrong.

 

[phil d]

Can't see why not as long as it has the right protection .      

I think the best ones are thise that you connect to a dead/off supply motor, spin shaft and it tells you rotation!

screw compressors really REALLY dont like reverse polarity, they sulk and go moody in a sort of ' phuttt BANG shear/snap ' sort of way.

the better ones have a reverse rotation safety interlock

these you mean, I have one and they are not too bad for the money.

https://cpc.farnell.com/duratool/d03121/phase-rotation-tester/dp/IN07441?st=phase rotation tester

 

[rapparee]

these you mean, I have one and they are not too bad for the money.

https://cpc.farnell.com/duratool/d03121/phase-rotation-tester/dp/IN07441?st=phase rotation tester

My multifunction tester has a phase rotation function

I thought that they all did