Bloody hell Tony,
Why didn't you say earlier,?
Can I come and stay for the weekend,?
I'll bring my own beer,
Why didn't you say earlier,?
Can I come and stay for the weekend,?
I'll bring my own beer,
Phase Rotation
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Help Support Talk Electrician Forum:
So long as you don’t bring disrepute on the house yes.
There’s a couple of electricians that will phone saying they’re on a call out and it’s a long drive home. I’d rather they crash on a make up bed in the lounge than wrap themselves around a tree through tiredness.
BTW,
I drink cider or rum.
There’s a couple of electricians that will phone saying they’re on a call out and it’s a long drive home. I’d rather they crash on a make up bed in the lounge than wrap themselves around a tree through tiredness.
BTW,
I drink cider or rum.
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Hi Tony,
Not sure what you mean when you say;
"If the incoming supply and all subsequent feeds are BYR can you explain where the problem is?"
I could reverse the position of the clutch and brake on my car, and put a sign on the dashboard. But why would i want to do a thing like that?/ Why would anyone not just swap things about so it would be RYB like it conventionally should be, instead of making things difficult for everyone else and wasting money on LOADS of little notices??
john..
Not sure what you mean when you say;
"If the incoming supply and all subsequent feeds are BYR can you explain where the problem is?"
I could reverse the position of the clutch and brake on my car, and put a sign on the dashboard. But why would i want to do a thing like that?/ Why would anyone not just swap things about so it would be RYB like it conventionally should be, instead of making things difficult for everyone else and wasting money on LOADS of little notices??
john..
Here’s a scenario for you:
A plant that from day one has BYR for its 3x7500KVA transformers. All 200+ motors are running in the correct direction.
John, a theoretical question for you:
How we alter things so as to be “correct” to convention?
BTW,
I never mind questions. I’m retired (not out of choice) so I’ve naff all else to do.
A plant that from day one has BYR for its 3x7500KVA transformers. All 200+ motors are running in the correct direction.
John, a theoretical question for you:
How we alter things so as to be “correct” to convention?
BTW,
I never mind questions. I’m retired (not out of choice) so I’ve naff all else to do.
I was always taught
The supply is not of your concern,
The rotation at the point you make your connection is.
Of course,
That doesn't apply for a new install.
The supply is not of your concern,
The rotation at the point you make your connection is.
Of course,
That doesn't apply for a new install.
Precisely my point, you work with what you’re given. No matter what that box of frogs hung around you neck says, you're stuck with it.
In our case it what was decided on in the 1920’s by the company. It’s not our fault the newly formed National Grid got it arse about face. I mentioned parts of the NW being BYR and 30° out of phase, that’s also the companies fault.
The intention was to build our own 33KV grid but the national grid came along so we tagged in to that instead.
Five of our local works had power plants each could be interconnected by about 40 miles of 11KV OH lines. The MEB took them over and they’re still in use today running BYR.
In our case it what was decided on in the 1920’s by the company. It’s not our fault the newly formed National Grid got it arse about face. I mentioned parts of the NW being BYR and 30° out of phase, that’s also the companies fault.
The intention was to build our own 33KV grid but the national grid came along so we tagged in to that instead.
Five of our local works had power plants each could be interconnected by about 40 miles of 11KV OH lines. The MEB took them over and they’re still in use today running BYR.
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Tony,
I'm sure I can remember doing some work on a small industrial place not very far from the steel works in s****horpe and the CT cabinet having a sticker on it saying rotation was anti-clockwise in that area...!
The 30 Degrees thing, vaguely remember hearing it happened with a certain reversal on the primary side of a delta->star distribution transformer.... but cant remember the ins and out of it?
I'm sure I can remember doing some work on a small industrial place not very far from the steel works in s****horpe and the CT cabinet having a sticker on it saying rotation was anti-clockwise in that area...!
The 30 Degrees thing, vaguely remember hearing it happened with a certain reversal on the primary side of a delta->star distribution transformer.... but cant remember the ins and out of it?
Reversed phase rotation at the intake isn’t a problem so long as all subsequent circuits maintain that rotation.
Phase angles are where it gets interesting. Twice I’ve been laughing my off socks as a result.
I transferred from the engineering department to production so was out of the loop for the first cock up.
It was decided to bolster the LV supply to a plant by adding a 3rd 1000KVA transformer. I’d installed the first two and was a bit miffed at not being involved in the 3rd. The “new” transformer arrived and was in its pen before I saw it.
New? It was 2nd hand and looked it.
Oh well, it’s non of my business let them get on with it. I couldn’t resist a quick peek at it on nights and was howling with laughter.
When it was energised I went in to the switchroom to see a gaggle around 2/3 bus-section switch scratching their heads. I walked out laughing. I couldn’t resist sticking my head around the door and innocently asking if anyone had checked the vector groups. I ran off before I was strung up.
Transformers 1 & 2 Dyn11
Transformer 3 Dyn1
60° out of phase.
The other episode was a bit more involved
Phase angles are where it gets interesting. Twice I’ve been laughing my off socks as a result.
I transferred from the engineering department to production so was out of the loop for the first cock up.
It was decided to bolster the LV supply to a plant by adding a 3rd 1000KVA transformer. I’d installed the first two and was a bit miffed at not being involved in the 3rd. The “new” transformer arrived and was in its pen before I saw it.
New? It was 2nd hand and looked it.
Oh well, it’s non of my business let them get on with it. I couldn’t resist a quick peek at it on nights and was howling with laughter.
When it was energised I went in to the switchroom to see a gaggle around 2/3 bus-section switch scratching their heads. I walked out laughing. I couldn’t resist sticking my head around the door and innocently asking if anyone had checked the vector groups. I ran off before I was strung up.
Transformers 1 & 2 Dyn11
Transformer 3 Dyn1
60° out of phase.
The other episode was a bit more involved
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Tony where they hot sticking across the bus tie and see weird voltages when you walked in? Good story though.
It was LV so a bog standard DVM.
Normal testing for phasing out, this is for a horizontal isolation switch.
R top → B bottom = 433V
R top → R bottom = 0V
Y top → R bottom = 433V
Y top → Y bottom = 0V
B top → Y bottom = 433V
B top → B bottom = 0V
R top → B bottom = 433V
Seven tests, you’re checking your meter every 2nd test.
Normal testing for phasing out, this is for a horizontal isolation switch.
R top → B bottom = 433V
R top → R bottom = 0V
Y top → R bottom = 433V
Y top → Y bottom = 0V
B top → Y bottom = 433V
B top → B bottom = 0V
R top → B bottom = 433V
Seven tests, you’re checking your meter every 2nd test.
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Ah woops missed the bit where you said LV in your story.
Phasing out on MV wasn’t my favourite pastime.
First time I did the tests it was the middle of summer (remember them?) PPE consisted of a teeshirt and shorts, last time I looked and felt like a star wars trooper.
First time I did the tests it was the middle of summer (remember them?) PPE consisted of a teeshirt and shorts, last time I looked and felt like a star wars trooper.
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Remember it well about 10 years ago, I was working abroad, 11kV board extension, full Kevlar padded suit and face shield and a set of phasing sticks, must admit I quite enjoyed it as it wasn't something that was done everyday, I was normally proving dead this was if you like, proving live and in phase between existing board and new section across bus tie before racking it in and closing.
This came about by the company using 6.6KV (don’t ask me why). Step down from 11KV to 6.6KV via a Dyn11, then step down to 433V via another Dyn11.
Normally it would be 11KV to 433V via a Dyn11.
End result 30° phase shift.
All MUCH too complicated for us mere mortals!!!
john!!!!!
john!!!!!
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ha ha!!!!
john,,
john,,
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