Confirming the correct phase sequence on 3 phase electricity supplies.
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No corny, irritating music playing and the content delivered to perfection - great educational videos.
As someone who is about to do the testing courses I found these videos extremely helpful. Thank you
It's pretty important to have phase correct especially on compressors where if it were wired wrong the compressor will run but the oil pump will be blowing bubbles into the sump instead of pumping oil through it, this is why compressors have the direction cast into the flywheel or crankcase.
Thanks John, this explains it perfectly!
Thank you, needed to change rotation on socket and this video was helpful, have a good day sir!
Thanks for the great video! As I've seen here in South Africa, the phases may not always be in the correct sequence. For example, my house has the red and blue swopped right up on the street pole. Always been like that. It's some sort of mix up between Eskom and municipal wiring changes. For municipal, on the 4 span overhead feed it should be neutral on the street side, then red, white, blue. But Eskom had neutral in the same place, then blue, white, red. The main feed from the transformer was replaced at some point and is now the municipal wiring whereas the house feed is the Eskom wiring. The only difference it makes is for the 3 phase borehole pump (changes the direction of rotation), but again it shows why it's important to test phase rotation (even on existing installations).
Love your videos, Would be good to see more on 3 phase
Thanks alot
Interesting. Here in the US, black, red, blue is typical for 208/120 -- brown, orange yellow for for 480/277. White or gray are used for neutral.
Beautifully explained.
Your videos have helped me to study and pass the Red Seal Construction Electrician exam in Alberta Canada...Thanks very much indeed, JW.
Hi John Love the Clips, have a question for you have you any experice or tested a Di-Log DL9110 Multifunction tester ?
Fantastic video, thank you.
Jw do you have any information regarding the AM2 test to get the J.I.B card, eg practical and theory
totally agree with you John on old 3 phase colours they where so much safer.
The new scheme is probably to do with the colours being distinguishable by colour-blind people.
Thanks for sharing, great content, to the point and efficient. You might crank out a Bach prelude there on that organ to close the show....:)
Thanks JW
Thank you for the video :)
Interesting John. Since I left the UK where was an electrician there are changes happening all the time. Never heard/ saw a phase sequence detector. If a motor ran the wrong way we change any pair but I see your point that sometimes you would need to know straight away before some machine got damaged if the rotation direction was wrong. Also the single phase voltage was 240, now 230 but the tolerance still allows 240 as its in range. The colours of 3 phase were red, blue and yellow ( sometimes white). ( My spell check here in the US is flagging colour as wrong, it wants color) The line to line was 415 v ac. Now about 400 eh. Times change.
it's all 'Nominal'. Normal voltages even for a newish transformer are 240 to 250v phase/N and 415 to 433ish phase to phase. I think they do this because it allows for more volt drop before the power companies have to do anything
The tolerance is +/- 10% of the nominal voltage.
Hi John could you do a video explaining how 3 phase works please From what I understand on a balanced load you don’t need a neutral but where does the current return ? Is it split between the other phases. Thanks
I always find it intresting how the countries develop with the phases. Around here for a long time the power companies will only deliver three phase to your premise, and you basically find single phase only in apartments where it was chosen to distribute different phases to different apartments.
Dennis Lubert in the US residential is single phase because the power demands don't require the extra current capacity and motor efficiency is not so crucial. Industrially the efficiency gain from running a 40 hp motor is substantial not to mention the lower construction cost for that unit.
otm646 I doubt that this is the reason, at least today it would more likely be the other way round. Due to only half the voltage, current capacity for delivering the same power must be doubled. So EU 230V has double the power capacity for the same wiring. Nothing in EU residential really needs three phase, but in a lot of places you can only get that from the power company, they won't even sell you single phase.
The quote I gave you is almost verbatim from one of my EE textbooks. The legacy structure in the EU is significantly different than the US method. Do you disagree on the point of improved motor efficiency on 3 phase?
otm646 No, but I disagree on the relevance of that for residential power systems.
To be fair, JW, I've never seen a three phase motor with a neutral connected to it in the whole time I've been an electrician. We always wire them in star as 400V. And there is no out of balance current.
Is there a way to check that the phase sequence is correct without a phase sequence tester? Without looking at the colours and matching them up at each end (supply to motor) I wouldn't have a clue which phase was which. 0_o
thank you for your videos, i find your diagrams and explanations easy to follow and grasp the concept in my head, your an angel may god bless you x
I picked up one of those electro-mechanical phase rotating indicators at a church table sale. Your video confirms what it is. I thought it was for phase rotation testing, but all the instructions were in German. Looks to be dating from the 1970's at a guess. Were any units made with lamps that illuminated in rotation?
+Hassan Burrows "Were any units made with lamps that illuminated in rotation?" Not sure if used for sequence checking, but we had a device in tech highschool, but with 6 terminals IIRC, but I only remember using it when we linked 3-phase generators together into a 'grid', so that the phases and frequency were sync'ed before the switch to connect them was thrown.
Michael Tempsch that sound really interesting. got anymore info
Sorry, not much - this was almost 30 years ago an d I haven't worked in the business (went for programming instead) I'd imagine the bulbs essentially measured the voltage difference between the respective phases on 'the grid' and the generator to be connected. When all bulbs were steadily off, the switch could be thrown. Different frequency would IIRC result in a pulsing voltage, right frequency but different phase or amplitude would cause a constant (50/60Hz) voltage difference. Having the sequence wrong would surely also result in lit bulbs.
I only know devices which have three lights for the three phases, and one light for clockwise and another for counter-clockwise rotation: www.benning-shop24.de/images/artikelbilder/Benning-Tritest-pro-020052-b_640x768.jpg The reflector is from the integrated flashlight. And the tester, could it be this device here? www.alte-messtechnik.de/hub/diverses/drehfeld.htm R: L1, S: L2, T: L3 "Richtig" is right or correct.
The one I bought is similar in design, I suspect an earlier design, because the unit is "hard wired" with a three core flexible cord and fly lead ends to connect to whatever circuit was under investigation. Thanks for posting the links. I will see if there is anything to identify my unit and post a link.
thank you SIR!
Hi JW love your videos, not sure where you are based but I’m pretty sure “normal” phase rotation here in the north east is anti-clockwise.
I've seen 690v isolators when walking through some buildings and also on testers such as your own one but I'm just wondering what that figure is there for as I'm positive they're 400v incomers from the dno. Is it just the rating of the isolator or did 690v used to be a supply voltage? Thanks
A J supply voltages are given and read as RMS not peak voltage or peak to peak. 240v Rms = 340v peak = 679v peak to peak. all exactly the same thing but measured diferently. then you have the tolerance to contend with. but the above are nominal values
John, Why in 3 phase installations is the voltage always refered to as "415 Volts 3 phase" but if my maths serve me correctly (Based upon single phase supply being 220 Volts) the total voltage between all three phases add up to 460 Volts? This may be a really obvious answer, but I've never been told! (Even though I am a qualified PAT tester!!!) Thanks Clive
The three phases are 120 degrees apart, so do not have maximum voltage all at the same time. The phase to phase voltage is 1.73x the single phase voltage, so for a 220 volt supply it is 380 between phases, 230 is 400, and 240 is 415. It's 1.73 as that is the square root of 3. If you draw a circle and put 3 points on the circumference 120 degrees apart to represent the three phases, then join the three points with straight lines you get an equilateral triangle. The distance of each side of the triangle, and therefore between each phase is the radius of the circle multiplied by the square root of 3.
OK thanks for that explanation John. Have a very happy Christmas, And I look forward to seeing more video's after the festive period! Clive
If I were to measure the phase rotation of a 12.4kV Switchgear, I’d want to do that on a aux power panel that is connected to a 12.4k/120V PT/CT?
Hello sir,Thank you for your great videos, I’v a refrigeration compressor works and then stops for less than a minute and when measured the current for 3 phases, I noticed L2 giving a very high current "3 times the normal value" and L1 and L2 normal, what is expected to occur this problem, Even though there is a failure phase sequence in the circuit.
Shorted winding in the motor is most likely.
@@jwflame thanks a lot
How can you tell wich of all thee cables is l1 l2 l3 is not marked on the disconect box
this is the 1st time I watch your video, somehow I believe that I heard your voice somewhere else before
we matching phase sequence but can we do LT parrelel voltages should match.across two supply sources voltages must show 0 voltages
Cheers!
HOW CAN FIND WINDING IN 9 LEAD 3 PHASE, AND WHAT MAKE A DIFFERENT BETWEEN STAR DELTA CONNECTION MOTOR AND DELT STAR CONNECTION MOTOR. MANEY THANKS . VAHID
Interesting. A few years ago we had a negative line fault from the power cables in the street. So we got that 400+ volts into the house, as did some of my neighbours. Lots of damage caused. Lots of time for all the repairs to.
Clive Geary where abouts was that, sounds interesting.
North Shropshire
How can I identify the ungrounded conductors color at a M-box?? I know they are black, red and blue but they are all black now. Would appreciate any help Thanks
thank you
I'm testing our industrial power grid and power extension cables/cords 400V (3x 230V) with 1 capacitor (2uF/400V) and 2 light bulbs 220V/60W (all three things connected in star connection). First light bulb lights more than other... If phase sequence is reversed, the second bulb lights more than the first. Works fine. engineering.electrical-equipment.org/energy-efficiency-motors/checking-phase-sequence-3-phase-supply.html
i was looking in a 3 phase board yesterday with 2 three phase circuits in, one circuit was brown,black,grey and the other circuit was black brown grey, why would this have been could it it jut preference to the colour in the SWA or was that to do with phase rotation ?
Brown, Black,Grey would be the usual arrangement, but it doesn't actually matter provided they are the same on both ends of the circuit. If it was different at each end the rotation would be reversed, which is not something that would be wanted.
Nice video..... Love from Pakistan
There phase colours in New Zealand is red white and blue with back neutral labels L1, L2 and L3
In Germany since 2003, actually same as the other EU-countries: L1: brown L2: black L3: grey N: blue PE: green/yellow between 1968 and 2003: L1: black (the black which is between the blue neutral and the green/yellow PE in a standard NYM-J cable) L2: brown L3: black N: pale blue PE: green/yellow before 1968: TN-C: L1: black L2: red L3: dark blue PEN: grey TN-C-S, TN-S or TT: L1: black L2: dark blue L3: black N: grey PE: red L1, L2 and L3 were called R, S and T. Red, white and blue were the old colours in the UK too if I remember correctly.
We have those same colours in South Africa too. L1=Red L2=White/Yellow L3=Blue Neutral=Black Earth=Green&Yellow (or bare copper sometimes).
How can I recognise which is L1, L2 and L3? No different colours on the cables
Hello I am watching your video all the time it's rely helpful & I have a question. How to check 3 phase ELCB by easiest way I don't have device to checked it , can you show me simple methods & thanks again , hope I can have the answer .
GOOD VID
can u do a video on how to wire emergency lights a wiring diagram would be great
Question sir John, Can we identify the rotation of the motor without connecting it to the supply?
Yes, there are specialised motor testing devices which can determine the rotation, such as the Megger MTR105.
How about in Fluke or Beamex, Do they have the same specialized tester just like Megger? I have a Request sir John, Can you make a video tutorial on how to identify a unmarked winding of the motor having 6, 9 or 12 leads coming out. Thank you.
What would the voltage be on a delta supply. I know phase and line voltage is the same so are all 3 phases 240 or are each phase 400
In the UK, it's 230V phase - neutral, or 400V between any two phases.
Hi, I have a plug its perhaps Swedish or german and has T, S, R written on it in place of L1 L2 and L3 might you know the sequence I have wires brown black Gray so they are ready
R-S-T = 1-2-3
Wouldn't a portable scope with a 1000 volt probe work well for that too
Obiously the earth is green and yellow but on a 4 pin plug, What lives will brown, black and blue go on for a bridgeport mill? (live1,2and3). My converter states the hot wires must go on live 1 and 3 what colours would these be out of black brown and blue?
If it follows EU colour standards, blue is neutral, black and brown are lines/phases. However what voltage it requires and exactly how those wires are connected internally is unknown - it must be confirmed before connecting anything as it's entirely possible someone wired it completely differently and didn't comply with any standard. May be that the three colours are actually all phases and it doesn't have a neutral.
is it a 120 or 180 degrees off set?
120 degrees.
Clockwise is mandantory. If it's counter-clockwise motors are rotating in the wrong direction. In case of a circular saw this could be very nasty. The saw blade could turn loose and fly away with much power. Nothing anyone wants to see...
Sir how about the red black and white?
I believe in North America, the phase colours are black, red, and blue. The neutral, when used, is white.
Can I as why you refer to the harmonised colours as 'unhelpful' John ?
Old colours - black neutral, blue phase. New - black as phase and blue as neutral. Black, brown and grey look very similar in poor lighting, red blue and yellow did not. Same applies to blue/brown compared to red/black.
Hello sir . Single phase preventer how to work in HVAC please explain to me. thanks
Thank you Sir for this video and explanation.
Without meter phrase sequence check pl explain
u forgot to highlight d high leg phase. when using the meeting
High leg delta is not used in the UK. The transformer is arranged as a star or Y, with the neutral derived at the centre point, voltage is 230V phase to neutral and 400V between any two phases.
And how do you test phase rotation? Lol
why do you lower your voice intermittently while speaking ?
thu nodakin henama gahapiya
your volume goes up and down hard to hear
50% wrong and 50%right If you want to discuss me reply me