Does Current Flow Through The Neutral Wire?
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День томуOne of the most amazing things about three phase electricity is that in a perfectly balanced system a neutral wire isn't needed. In this video, Joe Robinson shows how the neutral current sums to zero when an equal load is connected to each phase.
This helps to explain why the neutral conductor in a three phase cable is the same size as the other phases and why some industrial sockets don't have a neutral connection.
This electricians Q&A follows from our review of the Variabox, from CEENORM, which is a flexible power distribution system for industrial electrical installations.
👉 • This job could have be...
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00:00 Industrial Electrical Installations
00:42 Does current flow in the neutral conductor - yes & no?
00:50 Neutral current in a ingle phase circuit
02:00 Neutral currents in a Three Phase circuit
04:09 Lower than expected current?
05:08 No neutral current?
05:48 Why does this happen?
06:30 Electrical installations with no neutral
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#efixx #electricians #threephase
@efixx Рік тому
More electricians' questions answered 👉 ukposts.info/slow/PLmWOIPxaBWH7XMcW07S7CTQM9G-M1GHzc
@markhill9275 Рік тому
Actually, technically No. Current doesn't flow in a conductor, it flows around the conductor, or so i was taught at trade school. Current in the neutral must equal the current in the active, how else does an ELCB work!
@markhill9275 Рік тому
Try a star connected 3 ph motor
@johns9652 Рік тому
Don't know how UK electric works other than that you lot use 50 Hz instead of 60 Hz, but in the US you can't have 3 different devices share 1 neutral with 3 phase power. It used to be allowed, but the NEC was changed in 2014 I think. It's a lot of fun trying to fish 2 new neutrals in the old conduit to upgrade old buildings. (not) For fear of undiscovered nicks/shorts when the power is turned back on, oftentimes we just hook new wire with additional neutrals to the old, and use the old for the pull line to install the new and then recycle the old.
@murdo_mck Рік тому
A couple of gotchas with 3 phase neutral: 1) If there is a fault the absence of a neutral connection can allow overvoltage on the phase conductors without tripping breakers and the risk of shock or fire in any connected loads and 2) someone might connect a 3 phase + neutral appliance like an industrial heater to single phase power, joining all 3 phases together and tripleing the current in the neutral. Best case the neutral wire burns out, worst case the building burns to the ground.
@hugobrites6769 Рік тому
I just discovered this channel and I love it. I´m a Electrical and Computer Engineering student and love all things related to power grids and house installations, your explanations are more on a "practical" rather than theoretical approach and I just find it much easier to comprehend. Amazing work!
@efixx Рік тому
Cheers Hugo
@tonywebb9909 Рік тому
Yeah, I did learn this back when doing my C&G part 1, 2, 3. It was really nice to see it all again in video format. I think we did it all in formulas back then.
@jozefdkois Рік тому
I was trying to explain this to a cocky technician, who was 15 years senior to me. He was having none of it. I designed a control panel with a 3phase 2.5mmsq supply. There was a 16A single phase breaker on each live. His argument was that this arrangement would put 3x 16A=48A of load on the Neutral (2.5mmsq) wire. To prove he was right he even rang his mate, who was a lead in Intel, and they both were in agreement on this. Good guy though.
@totesmagotes3688 Рік тому
The neutral wire is the return path for unbalanced current in an AC circuit. It is not additive, it is subtractive. Put an amp clamp on the neutral wire of a nominal load, and you’ll even see that the current on the neutral will be equal to the current on the line wire.
@PORTEnSious Рік тому
Doesn't wire size limit current flow ??
@jetblackstar Рік тому
@@PORTEnSious yes wire size affects current flow as smaller wires can introduce greater resistant. But this is effectively in series so affects current through the whole of that circuit. Same way an appliance would affect current. V=I/R But that doesn't really affect the topic in the video. As what ever current passes still follows the rules they described. Hope that helps
@jetblackstar Рік тому
To be fair if it was the same phase they'd have been right. I think some brains just don't like coping with multiple phases. You'd hope better from an old boy though. 😁 They've had AC since Tesla lol
@totesmagotes3688 Рік тому
@@PORTEnSious Wire size doesn’t limit current flow, but depending on the size of the load vs. the undersized wire, what will happen is the wire will not be able to dissipate the heat generated quickly enough, and will cause rapid deterioration of the conductor insulation. Also what can happen is the the wire itself can melt, most likely at the point of termination closest to the load. A real life example would be a water heater that pulls 23 amps and is being fed from a 30A breaker @ 240V, but instead of using #10 AWG copper wire (which is rated for 30A using the 60°C in the NEC ampacity table 310.16 for residential applications). For the sake of this example, the installer uses #14 AWG copper for this installation which using the 60°C table of NEC Art.310.16, is rated for 15A maximum. In this situation, you have 23A running through wire that is rated for 15A maximum. In this install, you would definitely find overheating, burnt insulation, damage at the breaker and at the water heater disconnect switch, or directly at the water heater itself. One thing I forgot to mention is the ampacities mentioned are maximums for periods of time 3 hours or less. There are specific rules in the NEC I don’t have time to mention, but generally if a load is intended to be ran for 3 hours or more at any given time, it is not supposed to exceed 80% of the breaker capacity. For example, if a shop heater is rated to draw 24A, the breaker MUST be rated for 30A (30X.80=24A).
@flashesofblack4128 Рік тому
An outstanding presentation. I am a retired electrician and most of my work was done on 480 VAC three phase control circuits. I worked with maintaining large 50+ horsepower 2-speed motors and things like that. I also worked with DC traction elevator motors. I found it to be very enjoyable work. Your presentation is spot on!! I just subscribed so I will be seeing more of you. Cheers!
@robertpucovsky Рік тому
This is exactly what I was wondering for a while now so thank you for explaining. I knew three phase motors didn't need the neutral because it was a balanced load but for some reason it never occurred to me that heaters would also work the same for some odd reason. Clever stuff.
@FirstDan2000 Рік тому
It's good to b reminded of stuff like this, especially after not having to think about it in a long time.
@MarkSaeys Рік тому
That's so clear now ! 😀 Also, explains why the neutral doesn't have a bigger cross section cable!
@anthonyschofield7807 Рік тому
Which is why years ago we used to install 31/2 core cables as supply cable with a reduced neutral when the single phase loads were relatively small
@christvedt3852 Рік тому
This could also be drawn up as vectors. The phases are 120 degrees out of phase, a balanced load drawn as vectors would also show 0amps, and an unbalanced load would result in a vector length equal to the amps drawn in the neutral. That's how I learned it and understood it best in school, but this was also a great explanation! Nice and simple, keep it up! :)
@foogod4237 Рік тому
For anyone having trouble envisioning this, it's a bit easier if you start with something like American (two phase) house wiring, which comes in from the pole transformer as 240V, but with a center-tapped neutral wire. That means that neutral to either live conductor is 120V, so you basically have two 120V circuits, but each one is 180 degrees out of phase with the other (and typically half of the house circuits will be wired to one side and the other half to the other side). Because of this, if you need more than 120V for some appliances (such as many stoves, water heaters, EV chargers, etc), you can just connect them across the two different "live" wires to get total of 240V instead. In that case, you don't need the neutral wire, because all of the current going in on one side is balanced by the (exactly opposite) phase on the other wire going out. But it also means that on the neutral line going back to the pole, there may or may not be a lot of current, depending on how well the loads on the different house circuits are balanced. If you've got the same amount of stuff going on one half as on the other half, then all of the current will go "in" from live A to neutral, then from neutral to live B and back out again, and there will be no net current on the neutral line. However, if there's more load on the A side than the B side (or vice-versa), then all of that excess needs to go back out the neutral instead.
@bitTorrenter Рік тому
Thanks for this explanation on the US voltage supply.
@deang5622 Рік тому
FFS! If you have trouble envisioning it then go back and re do your entire electrical training! It's that basic a question. And if you don't know the answer to it, you shouldn't be anywhere near mains electrical installations, even if you are "qualified". Because for you not to know the answer means that: 1. You have forgotten your basic electrical education, and 2. That you don't really understand electricity.
@greenpedal370 Рік тому
180deg across the phases. You sure about that?
@deang5622 Рік тому
@@greenpedal370 Yes, he is quite correct about their being 180 degree phase shift between the two lines in the US split phase system. If you know enough about sine waves and electricity, you will realise that 180 degrees is the only way that is possible. If you think he is wrong because you think it should be 120 degrees, then that is certainly incorrect. 120 degrees phase shift between phase conductors only occurs in 3 phase systems. And that is because they physically position coils around in the generator at 120 degrees around the rotor. In the US split phase system, the phase signals that are distributed to consumers do not originate from the power station and generator, they are produced by the down stream distribution former and is a result of how the secondary windings are connected. It's very different to 3 phase.
@Mike_5 Рік тому
wow that explanation made my brain hurt
@ryzlot Рік тому
I knew this BUT you actually found a way to test and teach the theory. GREAT JR
@JJ-zg1hh Рік тому
This video just blew my mind. Great information and really clearly presented.
@gbelectricks Рік тому
Your video on your “Joe Robinson” channel on this same subject (a few years ago) was the moment the penny dropped for me! Very well explained Joe & @efixx👏
@DesperateDan3231 Рік тому
Mind blown, but it all made total sense when you showed the wave form graph 👍
@jassihra8566 Рік тому
You are absolutely amazing! I wish ( and I sincerely mean this) I had this tutorial video when I was doing my A levels!
@Bari_Khan_CEng_CMarEng 5 місяців тому
Great video and practical example of some basic electrodynamics, much appreciated
@Dog-whisperer7494 Рік тому
Now that I found very interesting and informative thank you Joe excellent explanation. Fantastic video as always Joe 👍❤️
@sabaabdullah7110 Рік тому
Hats off to you sir ... really thank you for the simplicity ..
@sapphirepilot Рік тому
Great demonstration. Thanks. I know it but it is nice to hear/see it again.
@TigerP1 Рік тому
My father taught me 3 phase theory 42 years ago. I never needed it but I see I still remember it correctly.
@christopliss9947 Рік тому
Brilliantly explained as usual thanks 👍👍
@agboolajohnson.s.2557 Рік тому
Wow, I’ve been looking for this. Thank you
@Beariam24 Рік тому
Always remember a site we took over from a previous company. They told the customer that all the 3 phase circuits had no neutrals and they all needed rewiring… just showed lack of knowledge on the subject. Maybe more should be taught about things like this before people are let out on the wide world 😅 Neutral in a 3phase is generally found if the item has other elements eg control panels and other single phase components with in the 3phase item. Great video guys!
@oal2928 Рік тому
Fun to watch, when you already know why and he explains it well :)
@garythespark6295 Рік тому
Very interesting video as always. Love this channel 🙌
@batmanpaul1 Рік тому
Gray video and great explanation. Big thank you 👍🏼
@miiuelyza9754 Рік тому
Great Video, very helpful. Thank you guys!
@sergiofernandez3725 Рік тому
Great explanation Joe.
@efixx Рік тому
Cheers Sergio!
@MalaysiaBarista Рік тому
This is spot on . I think most people missed the fact that , even though you don’t need neutral , and depending on what you are running , and in this case 3 units 1 phase heater: it is safer to run a neutral at 1/3rd the max amp capacity , in this case and if in the event if one of the 1st phase heater encounters problems .
@tlangdon12 Рік тому
It would appear from the video that you need the neutral to be the same size as the phase conductors, as if one heater fails you need to be able to carry the full rated current of the phase conductor.
@sirfyaz1886 Рік тому
🤯 Wow, that was explained very well. 👍🏽
@haidarbadavi9460 Рік тому
Thanks very much for your time and effort
@muzikman2008 Рік тому
Interesting stuff...I was expecting "it depends on if it is fed from a Star or Delta transformer..." great explaination.
@jonathanbuzzard1376 Рік тому
I challenge you to actually disconnect the neutrals with running equipment 🙂 Actually that would be a *really* bad idea. Happened at work once in the distribution board (faulty installation, took a couple of years to fail after the building was constructed). The insurance claim was I believe in seven figures and we were super lucky the building was not burnt down. Helped that the fire station was just across the road and they responded in under 90 seconds.
@efixx Рік тому
Used to do this on a similar experiment for my learners...
@jonathanbuzzard1376 Рік тому
@@efixx For those that don't realize no neutral and all the lives float to 415V AC. The fire was started when the 400V rated capacitor in the power supply of a PC decided that being at 580V (415*sqrt(2)) was not good and flames came out the back of the PC (the slowmo guys have some nice footage of capacitors giving way), and set alight to the noticeboard behind (this is why the mains smoothing capacitor in a SMPS should be rated for 600V). The reason for the really high insurance claim was this was a biosciences lab and at lot of the very expensive equipment didn't take kindly to the 415V AC feed to them.
@Poorlybobsdad Рік тому
If it was unbalanced, the current would be present at the end of the disconnected Neutral. The equipment would look dead, right?
@okaro6595 Рік тому
If you had just one heater and nothing else there would be no current flowing. If you had two heaters each 80 ohm (720 W) you would have 415 V over 160 ohm. That is 2.6 A and 1080 W (540 W each). That is if you have three identical resistors on a star connection with the neutral is connecting one reduces power by a third and two by 2/3. If you do not have a neutral then disconnecting one reduces power by 50% and two by 100%. The real problem is that if you have some other loads in parallel like an incandescent bulb with 960 ohm. If it if gets in series with the 80 ohm heater at 415 V it gets 383 volts, i.e. it gets 2.5 x the power and will not last long. If you disconnect the neutral upstream from the main panel then the voltage in it gets to the earth wire.
@SeanBZA Рік тому
Had the neutral at the substation vanish with thieves, and the phases started to diverge on all the houses. Had the UPS start to warn about overvoltage, so measured mains at 270VAC. Immediately turned off all loads, and turned off the mains to the entire home as well, then went to the meter room and checked phase voltages. One was at 270VAC, one was around 230VAC, and the third was around 170VAC. Turned off the entire building, and got on the phone to the metro about a loss of neutral at the substation. Took them most of a day to fix it up, and they came back the next night to do it again, so they put up the steel doors instead of the wood, and welded all the cable access covers on, that they used to strip the SWA feeder cables leading to the street.
@hishamalzaben Рік тому
Thanks for the topic, effort & way explained.. Q: Why sometimes we find current flowing even thu breakers are off mode..
@martinbateman2467 Рік тому
Nice video, very informative
@rob3125 Рік тому
Very good explanation with examples. 👍👍👍👍👍
@mohamedabdelmonem6468 Рік тому
Wonderful explanation . Thanks.
@sergioro8_125 Рік тому
Brilliant explanation
@efixx Рік тому
Thanks
@johnwarwick4105 Рік тому
Interesting demo. Will be valuable for all those domestic sparks that never get involved with three phase systems. Came across a large lighting circuit like this some time ago, gave me a bit of a head scratch till I realised that the neutral current will never exceed the current of one phase
@deang5622 Рік тому
Those domestic sparks that have only undertaken the domestic installation courses are not allowed to do 3 phase work (in that they are not allowed to do industrial installations). And if people are qualified to do industrial electrical installations then they have been trained in 3 phase and should not need this video.
@efixx Рік тому
You woke up on the wrong side of the bed Dean? The video could be helpful for people who are in the process of qualifying for carrying out industrial installation work? 🤷
@johnwarwick4105 Рік тому
@@efixx quite agree there are plenty of time served industrial engineers that I know that would have to head scratch about this one
@karaffens Рік тому
@@deang5622 in many parts of the world its normal to have 3 phase power in your home, even in apartments...
@OldLordSpeedy Рік тому
Do you mean "domestic spark from UK" only. All other domestic sparks around the UK (and commonwealth and U.S.A. ) use three phase connection to every house/garage/shed/fabric hall since Siemens & Halske around 1880 use 3phase AC and build the generators around the world!
@johnhatton7137 Рік тому
Very interesting and well explained. However, if the incoming neutral becomes disconnected as I have experienced at a heritage railway, where the unbalanced loads caused serious problems with some devices burning out and other loads suffering low voltage. There seems to be no protection against such a problem and the supply company sometimes won't admit there is a fault.
@katiefinnegan4649 Рік тому
That was excellent work.
@chrishorne3185 Рік тому
Another great video Joe 👍
@brianwood5220 Рік тому
Great explanation Joe
@efixx Рік тому
Thanks Brian
@Holdeenio Рік тому
So when you had two heaters connected and measured the current on the neutral, it wasn't the same as L1 + L2 because it was partially mitigated by the opposing phases, but not completely as it was when you activated the third heater? - fascinating.
@Marcel_Germann Рік тому
That's the reason the 400V continuous flow water heaters with 22 or 24kW, that are popular here in Germany for electric water heating for showers, don't require a neutral at all. In most cases we still install a five core cable. The five core NYM-J is only 1€ per meter more expensive than the four core one. Neutral isn't connected of course, but still available if it would be required in the future.
@sstorholm Рік тому
It’s a really good idea to pull the neutral always for future use, here in Finland it used to be acceptable to wire 3-phase sockets with no neutral, if they were intended for a large machine, it’s really fun when you rock up with a portable distribution board to only find that they left out the neutral. And it’s no fun either to have to install transformers for 400/230 just to get some new-fangled boiler with a control board that needs a neutral working. :)
@Marcel_Germann Рік тому
@@sstorholm Or you install another motor, some require a neutral just to start, and while running it's disconnected.
@sstorholm Рік тому
@@Marcel_Germann What sort of abomination of a 3-phase motor requires a neutral to start?
@Marcel_Germann Рік тому
@@sstorholm Not the motor itself, but eventually the electronics that regulate the speed of the motor. And maybe contactors if you want to reverse the direction of rotation. And also possible, the future replacement requires for other reasons 230V in addition to 400V. Unlikely in industrial applications, but not unthinkable, and in domestic applications this can always happen. I remember my grandparents had a Perilex socket outlet (three-phase socket outlet )in their bathroom for the washing machine. The plug always "wandered" from the old to the new washing machine because it was the old rare 25A version.
@GhostyGamer Рік тому
That's an excellent explanation .being a growatt service engineer, I was wondering why the ongrid inverter works fine without neutral.
@arisk4 Рік тому
Very good explanation. Thanks
@AirArtStudiosOfficial Рік тому
I just done an energy study on a school and had upto 60A running through the neutral which I thought could be the difference between phases and all the different loads over the school. Drawing around 250A per phase
@dazdaz105 Рік тому
A good demonstration for non Sparky’s to understand 👍
@davidwood639 Рік тому
I've come to the conclusion that I am 'Electro-blind' !!! I love videos like this one and it is extremely well presented but I just can't get to grips with the physics of electricity lol. Keep up the good work and I'll just be happy I can change a 3 pin plug!
@thusithasampath3089 Рік тому
Great Explanation 😍
@flyingtools Рік тому
Very good video and information. Thanks👍🏻
@oldscar6169 Рік тому
Great explanation thank you
@halamish1 Рік тому
Excellent presentation
@efixx Рік тому
Thanks
@danielmarcusaurelius3835 Рік тому
great explanations. great channel
@TechwithStefan Рік тому
very nice demonstration of Kirchhoff's current Law
@Dog-whisperer7494 Рік тому
I received my new TIS voltage indicator today thank you eFIXX. It’s a great bit of kit , very much appreciated.
@efixx Рік тому
Great to hear!
@smokeybobca Рік тому
Thanks for the current measurement on the neutral with the two loads on L1 and L2. Both because it's not intuitive, and will force me to interpret the KCL and the desmos graph on my own as an "exercise for the reader". Where in the circuit are the neutrals of each of the individual phases physically connected? Within each of the outlets on that piece of plywood? The diagram at 5:36 shows the conceptual drawing; but where is are the physical connections of that neutral in the Y-config?
@TheNewFaceOfHSP Рік тому
Hello, I just looked up this information and found your channel. My dad is an (old time, retired) electrician and has taught me to do basic electric work. I replaced a ceiling outlet (lighting) and instead of turning off the circuit, I just turned off the outlet as it's and old house and it's supposed to only have 2 connections (phase + neutral, no earthing) in most places. Turning off the phase should do the trick, and even if there is some leakage, it should only tingle. I verified everything with a basic "glow lamp" style seeker. No phases. And then verified with a multimeter - No current flow from L1 to Neutral. However, I noticed the neutral had 2 wires attached. That was peculiar,but I thought it might just be sharing a neutral with some other light or WTF knows? It shouldn't be an issue. When I disconnected the L1 from the ceiling outlet = no issue. When I disconnected the neutrals, small spark and the lighting on the walls in that area of the living room (supplied by wall outlets) turned off. Interesting. I shat my pants, stepped down from the ladder, took a moment to check myself, wondered why the RCD didn't trip (obivously it only sparked, didn't touch me in hindsight) and then turned off the entire house main feed. I'm not messing around anymore when neutrals and phases are mixed around everywhere. Anyway, I told my dad and he refused the possibility of electricity in a neutral. I told him electricity is defined as a difference in charge, and there should be current flowing return in the neutral. Now I understand it better, and I'll show him this video. (Also, I'm the EU with a proper RCD and I use VDE tools with the 1-hand-behind-the-back principle when doing semi-stupid shit like this. Worst case is going to be a zap until the 30ma RCD cuts out)
@phildxyz Рік тому
Many moons ago I was working in a computer factory (not as electrician :) ) when a cloud of acrid smoke tripped the fire alarms. Turns out the busbar chamber had a reduced size neutral, as the load was considered pretty well balanced. Ad Hoc alterations had seriously unbalanced the system and the neutral was glowing red hot with all it's PVC insulation burnt off! Turned off and fixed, with half a day's production lost, but could have had much more serious consequences.
@mrwhy8073 Рік тому
The neutral over heated due to harmonics. Most times it is the 3 rd harmonic. It is a result of having loads that are non linear to current. That is variable frequency drives, computers, discharge lighting etc.
@dimitrisblane6368 Місяць тому
Thanks for the vid. So if a 3 phase motor needs no Neutral how does the current travel back to the source?
@amitkumarsingh5822 Рік тому
Very good explanation
@namajkatiufputkata Рік тому
great explanation!
@drivingparadox Рік тому
I’m not a sparky yet I understood it. Thank you.
@johnmarkgonzales8791 Рік тому
Legend! Keep it up!
@diablo1271 Рік тому
Very well explained from average person point of view. THANK YOU GUYS
@tygerovi Рік тому
Subscribed! Very nice and informative! thanks!
@DeezNutz-ce5se Рік тому
Absolutely. I've seen many a live neutral. Never touch without testing.
@rondo122 Рік тому
excellent video, congrats!
@anthonykinrade8642 Рік тому
It's simple. The 3 phasers are vector quantities and therefore add up to a resultant vector in the neutral depending on the magnitude and phase displacement. Electricians were taught this as part of their apprenticeship in my day...
@JC-jv5xw Рік тому
One way of thinking about this is that the neutral current is the total phase imbalance. One phase loaded(= 1kw imbalance). 2 phases loaded (= 1 phase = 1kw imbalance). 3 phases equally loaded - no imbalance.
@beendoneagain Рік тому
Great video. Thank you
@Timmerdetimmerdetim Рік тому
pretty much exactly. A new way of saying things :)
@Ste2023 Рік тому
Important info ... Thanks efixx
@mhikemars2971 Рік тому
Great video. Well done. But it is clouding up the subject a bit. Of course, using three phase for single phase devices happens all the time, but single phase devices use one two hot lines. 120V and 277V devices use one hot line and neutral. 208V and 240V could be either one hot line and neutral or two hot lines and 480V is always two hot lines (all examples are single phase). I would like to see this using a single-phase supply, L1 of the 240V single phase supply wired to all three heaters in parallel, then check the neutral amps as each heater gets energized. A previous comment said the standard residential supply is two phase because of the two hot lines. That is wrong. The standard residential supply is 240 Volt, Single Phase. Best Wishes. Hope you keep up the good work.
@AtanasPaunoff Рік тому
Couple years ago I used 3 phase for powering a few dosens of single phase crypto mining RIG's... At some point I check the cable and it was so hot. Then I did same as you mentioned to balance the phases and voila cable isn't hot anymore :)
@Savagetechie Рік тому
I would clarify slightly in your eater example, if you disconnected the 3 individual neutrals all 3 heaters would switch off but disconnecting the common point they would run in a star configuration. I know most viewers will know thats whats happening but just for clarities sake.
@brianhewitt8618 Рік тому
it would be good to see a video on that 👍
@Savagetechie Рік тому
@@brianhewitt8618 star points are an interesting thing as is generator earthing which is a related subject. Not sure if efixx will cover them but maybe sparkyninja?
@alunroberts1439 Рік тому
I worked on a 3 phase oven a big big boy oven. It needed a neutral. It was 3 phase but worked as single phase. As each pair of elements. Was only on one pair at a time.
@KevinCoop1 Рік тому
What was the voltage applied to the heating elements? 416 or 240 volts? Sometimes the elements are 416 single phase and multiples of three, and the controls are rated at 240 volts. It could be either way, just how they are connected in the equipment. Best wishes, Kevin
@alunroberts1439 Рік тому
@@KevinCoop1 Don't recall now just the way the contactors were wired up. Do think somewhere I have a photo of the front so I will look it up one day.
@zanu36 Рік тому
Great job! 👏 👍
@Jp-rp3ds Рік тому
The heaters are rated at 230vac input. Line to line voltage is 400vac. Square root of 3 (phase system) is 1.732 and is always applied to power calculations. 400vac over 1.732 is 230vac, which would be measured between any line and the common point. 3 phase resistive load; Ib = P/Vx1.732
@herhua69 Місяць тому
Hi what is be the most likely cause of over-voltage in a 3 phase system? One of the phase was found with voltage of 385V and it tripped the CBs and caused damage to equipment that were connected to the phase.
@thesparkingwire Рік тому
Loved it 😻
@ritzevespa Рік тому
Yo, this is magic stuff 😍 Iam just rolling into big buildings with 3 phase ac and hi power pumps and motors I'll stick to this channel Fwy, I imagined that it has to do with the 3 phase, if you would add up the 3 loads trough the neutral it should be way bigger than 2.5 2 waves can cancel each other out. Dad was a guitarist 😅
@kukifitte7357 Рік тому
Great video 👍
@pyhead9916 Рік тому
If your circuits are not balanced in the breaker box, you can get current flowing on the neutral line. Also, if the protective covering on the wires feeding your breaker box crystalize, you can also generate current flowing on the neutral line. You can argue with me all you want, but I learned this through experience when we installed a minicomputer in our newly renovated building. The computer was blowing boards every month, so we put a line analyzer on the system and discovered current on the neutral line. Apparently, computers do not like current on that line. Upon diagnosing the problem, we discovered what I mentioned above. Once we fixed those two problems, the current was no longer found on the neutral line.
@davesmewing2534 Рік тому
I learned all this when I was an apprentice 60 years ago.
@qasdw6 Рік тому
I have a question, if in 2 phase circuit you have exact the same current in the neutral is no current used in consumer? and if so why we pay for the production of current and not just transport and distribution.
@Supep007 Рік тому
cool to see it explained this way... so does that mean that the power company 'meters' actually measure each phase individually for calculation of how much to charge us for power?
@HenryLoenwind Рік тому
Yes, and then they add the 3 values together. Unless you're an industrial installation that gets charged for the imbalance, then there's a fourth meter on the neutral.
@glyngibbs9489 Рік тому
Thanks that was excellent. I've had this "discussion" many times with " professionals" who did not want to put a neutral line in at all. But you have raised a doubt now! If you remove the neutral from your star winding drawing doesn't it became 415 instead of 240? Sorry but that's a stupid question I hung the screwdrivers up a long time ago!
@pv2b Рік тому
The way to get to 415 V given three-phase 240V, is to connect between the phases in a delta configuration, not a Y configuration.
@dimitriderop2543 Рік тому
do the same with 3 x non-PFC power supplies (like your laptop's PSU) Even when all lines are balanced, you shall see a current in the neutral. The 3rd current harmonics are summed up in the neutral
@phildxyz Рік тому
Well explained, but any electrician who does not know this should not be let loose with a screwdriver!
@efixx Рік тому
New people train to join the industry every year - knowledge is power.
@pedrojardim325 6 місяців тому
Good stuff very. Interesting
@pauljanssen7594 Рік тому
When you study the history of electricity outlets plugs first it was two basically hot and neutral current flows both ways then due to electrocution shocks TVs radios your other appliances the two outlet had a wide and thin blade plug so the wide blade was neutral thin blade was hot. This specially helped in grounding chassis on radios and TVs. But because of the human factor they came out with the plug with the third terminal round called the ground this was great for grounding washing machines and electric motors the second plug design was great for ground chassis on TVs radios sewing machines mixers you name it it was a big improvement. Unless you're ground is tied into neutral at the main panel it's of no use to save anybody's life from electrocution.
@KevinCoop1 Рік тому
Correct statement up to the point of a GFCI breaker installed in the circuits. They require no ground to operate and protect life from shocks or electrocutions.
@trevorlonewolf6406 8 місяців тому
What could the problem be if the Neutral is higher than the combined L,1 L2 and L3
@chieftain8638 Рік тому
Finaly an answer to a question
@alanrobinson847 Рік тому
If you're interested in electricity kirchoffs law is pretty interesting as is thevanins theory, not super heavy in maths but worth a look in my opinion
@jephthahjackson1095 Рік тому
@tti that packs a punch..good explanation
@ia4387 Рік тому
Great video here Joe, can I ask if you have a 3 phase motor which draws 60 amps for example, does 60 amps flow in each phase or does it get divided into the 3 phases i.e. 20 amps down each phase?
@haidarbadavi9460 Рік тому
Motors are rated w/ s/ phase. So its Amp per phase
@ia4387 Рік тому
@@haidarbadavi9460 Just to confirm it's 60amps per phase.
@KevinCoop1 Рік тому
@@ia4387 If it is being called 60 amps three phase, you will get three 60 amp readings, not three 20 amp readings. Hope this helps. Kevin
@joedixon2864 Рік тому
3 phase Motors are usually shown as Amps per Phase. 'Rule of thumb' 2 amps per KW. Takes account of power factor and efficiency.
@tuongtrinh4982 Рік тому
amazing video
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