Nice way to test motors with special equipment! I like your explanation about insulation molecules, I have experienced a climbing IR value before. Electrical teachers normally just tell you to pee on something to help with continuity values, they never mentioned holding an IR test.
You are just perfect in teaching. My gosh I wish other teachers would take a page from your book so they can stop teaching like you're making scrambled eggs.
I’m so glad I found this channel. Believe it or not I was wanting a “how to” video buy someone who knows a little more then if the multimeter beeps or not. In the words of G. Marx... I thankque!
Thank you sir for your generosity I appreciate it, I work with some plonkers when it comes to see how they do installations they send me to get coffee for them!!!and this happen all the time.
Yes. star/delta, 6 wires back to a starter, connect in star or delta depending on your supply voltage. Also each winding has a start U1,V1,W1and finish U2,V2,W2 mix them up and your in trouble. Normal practice is to bring the start out of the motor together and finish out together.
I had a motor come back from being “rewound” and one set of windings was mislabelled. U1 & U2 were backward. This caused the motor to draw about 185% of full load current. The motor ran slow and erratic with no load. I found the winding that was backward and relabelled it and tried it again and it only drew less than 40% of FLA with no load on the motor. Finding the three windings is the first step, then you have to find which ends are U, V & W 1 and which are U V & W 2 because when they are wired up they form a phaser diagram for current. Each should be 120 degrees apart. If a winding is backward, one current will be between the other two on the short angle. Let’s say all windings are okay and the currents are 100 A at 0 degrees and the second is 100 A at -120 degrees and the third is 100 A at +120 degrees. If the third winding was wired backward because it was mislabelled, then the currents would be: 100 A at 0 degrees and the second is 100 A at -120 degrees and the third is 100 A at -60 degrees(+120 degrees - 180 degrees). If you plot them you will see why the current is so much higher at no load. If it was a perfect motor, the current would be 200%. If this still doesn’t make sense, plot the voltages and currents in each winding on a phaser diagram and reverse one winding and do the plot again to see the effect when you add the currents.
Great video, very concise and clear. I'm trying to run a three phase motor on single phase. Do you have any advice for a formula to determine capacitor size for optimum power and minimum heating? Thank you
Good video, but would have like to have seen you phase out the windings for Start and finish or 1 & 2 of each winding...before connecting in star and saying it would run correctly. Good chance a winding is in opposition to the other 2.
thank you. this is perfect explanation. on my way to test a 3 phase, dual motor, compressor. its popping the beaker every couple of hours or so. I wanted to get a quick refresher. came to the shop to pickup the fluke scope, clamp and my old all-test. Usually i work on single phase stuff. when it gets to 3ph, mainly cuz I get to use my tools I get a little jittery and excited about it, hehehehe can polarization test be used on a single phase motor as well?
The large 3 phase motors I've come across are wired with the coils not aligned on the terminal block i.e W1-U2, V1-W2, U1-V2. This means you can wire them star or delta by moving the copper jumpers. Why would you wire this motor W1-W2, V1-V2, U1-U2? Is it not made to run in delta configuration? Wouldn't it be safer to wire it W1-U2, V1-W2, U1-V2 in case someone wires it into delta; to prevent a short circuit?
Yeah, I think it should be wire as what you said, U1-W2, V1-U2, W1-V2, so that easier for us to change the copper plate with vertical or horizontal directly for both Delta or Star connection respectively. But for Star Connection in this video, maybe he just don't care about that since it's for Star only, of course for safety consent, it should be like what you said.
You would never set the six ends in this configuration. The top set would be moved one place to the right so vertical delta links didn't link both ends of the same winding. ( I know this was star but you just don't do that). Also should have explained that the ones and twos must be at the correct end. Instant burnt out motor if not. Without manufacturer data you can only assume that all 3 ends from one side are ones and all 3 from other end are twos. Also you don't run 6 ends back to the starter unless it's star delta. You did say for delta. You also said contractors change from delta to star, this would be the other way round in star delta situation. The order for terminal posts could be / top row , W1/U1/V1, bottom row U2/V2/W2. So giving two different winding ends to each vertical pair. ie. (w1/U2) ( U1/V2) (V1/W2). I know there is a lot of good info here but there is also a fair bit of confused info here that will baffle learners.
I picked up on all of these and I don’t understand why he is using cable instead of the normal plates! Also got me confused when he said that you must run back to a contractor for delta?? Also even if your motor is on a inverter you still need the 1s and the 2s the right way round
Hi there, I have recently discovered your excellent videos. I am just starting out in electrical maintenance. Could you recommend a good multimeter and megger. Also any other recommendations for testing equipment..... Many thanks
Yes. Pick a different field of work. 20 years from now you’ll be wondering how the hell you thought this shit would be cool to do for a living. Hot factories, grease monkey, product in every crevice of your body. Did I mention it’s hot! Shirt soaked every night. If you are lucky you will have a boss who won’t make you do project work while also running the floor fixing breakdowns. Emergency breakdowns are the worst. If there is an oven or many ovens in the plant - run! And don’t look back. Shoot! What the hell was i thinking!!!?
See my comment above. Its called phasing out and using the visual effect of Lenz's Law...Using a 6 volt battery and a anologe volt meter on 10 volt or less.
WRONG! 1st. You should look at the terminal board, it should read U1, V1, W1, V2, W2, U2, not important in star only. 2nd. What is difficult with 6 wires like that is to figure out which one is 1 and which one is 2 that have to be correct in both star and delta. 3rd. On motors with light load there is no need for a star delta starter (they are becoming obsolete because there is many better ways to start a motor today), and you can start the motor in delta with a VFD 4th. Even when you use a star delta starter it's nice to connect L1, L2 L3 on both top and bottom terminals
That terminal block is going to going bang if someone ran delta links. The Windings should be offset on the block not aligned with each other. IE if you connect three phases then each end of a link will connect 2 ends of A DIFFERENT winding. Its dangerous to connect a winding block to only accept star links where as offsetting the windings allows for either star or delta by just changing link configuration.
Why did you do the test with 500V ? Can we make it with 1000v ? And if it can be done with 1000v will we expect the same value after deviding the 10min and 1min ?
Furthermore, it is always best to know a complete method as opposed to relying on labels so this is a more useful methodology than is simply assuming designations are correct ad nausea
at 9:30 you said that the polarization currents runs through the insulation because it could find paths through the un-aligned dipoles, but this is not accurate. The polarization current exists because of the time changing polarization density which induces the current. J = delta(P)/delta(t).
In terms of U, V, and W wiring assignments, did you do that randomly? How did you know which letters to give to which wires? Is it a standard configuration ?
Do you have to do the polarisation test on each winding? Also where abouts is the earth wire in that terminal block? or is it just to the body of the motor somewhere? Also what about the neutral wire?
Delta connection will not work. Also how do you know if a wiring is not swapped. I mean wether one of them will produce opposite magnetic field. Am I right?
hello sir,Thank you for your great videos, I’v a refrigeration compressor works and then stops for less than a minute and it’s circuit breaker cut off, when i 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
It’s either that in your system they are using your L2’s 230V to control a light or the control circuits or you are experiencing a motor that is unbalanced and you’d be expecting very low resistance on L2 due to the breaking down of windings
Ohm's law, voltage = current * resistance. If your current has gone up, your resistance has gone down. The winding would have failed insulation about 1/3 along its winding, shortening the length of the active winding, thus lowering the resistance. If the winding draws 3 times normal current, then the motor draws 5/3 of its rated value. Circuit breakers used in motor protection take longer to trip, as to allow for the high start up current of motors. Phase protection is to save your motor from running on two phases if one phase goes down.
I have a motor I’m trying to identify the windings on, there is 12 connection, I can see there is 6 pairs. It was operating as 2 speed on the machine. I need to wire it at 2800 delta to connect a VFD, any idea how to identify which is which ?
I got a 3 phase motor i like to hook it up to a single phase vfd i know i need to set the motor for delta, and they have been paired. but my problem is there is no u v w labels does this matter can you "call them anything like you say"
He connected all 3 windings together, so no. You'll just be testing all 3 at the same time. I like to disconnect them from each other and do the test on each on though. Proves they're ok on their own.
Hi, I can't understand why you didn't do an insulation resistance test from motor windings to earth, from the start of testing..... if there's a earth fault on the motor, why carry on.
I'm from India.I'm general mechanical technician.3phase motor like 3wire I mean uvw.or ryb.star connection to connect u1-w2,v2-w3,w3-w1.,we can check amp minimum value it's coming every star connection motors condition ok.in 3connection any one less.that motor has ground.replace another motor
@@DipakFalane-es5ue no. If you do it wrongly it will burn the motor. One of the magnetic fields might be reverse compared to other two if you connect wrongly
Just checking for continuity across your windings will not tell you if you have a shorted winding. You have to check the actual resistance value of each winding and compare it to the others. The ohmic value should be very close across all windings.
Muziwandile Mazibuko . If you test the resistance of each winding using an accurate meter like this , you can check for damage within the coil such as a short circuit resulting in a lower resistance reading or an overheated coil due to a bad contactor will show up with this test . This kind of damage may not be apparent otherwise.
Nice way to test motors with special equipment!
I like your explanation about insulation molecules, I have experienced a climbing IR value before. Electrical teachers normally just tell you to pee on something to help with continuity values, they never mentioned holding an IR test.
It is a Megger MIT 400. Very good piece of equipment
You are just perfect in teaching. My gosh I wish other teachers would take a page from your book so they can stop teaching like you're making scrambled eggs.
You always bring light into my brain! Thanks for that! The people who work with you are probably the luckiest people in UK
I’m so glad I found this channel. Believe it or not I was wanting a “how to” video buy someone who knows a little more then if the multimeter beeps or not.
In the words of G. Marx...
I thankque!
Thank you sir for your generosity I appreciate it, I work with some plonkers when it comes to see how they do installations they send me to get coffee for them!!!and this happen all the time.
That's terrible of them! I hope you get to work with nicer people who value you as an equal member of the team. All the best!
Good video mate, cheers!
Yes. star/delta, 6 wires back to a starter, connect in star or delta depending on your supply voltage. Also each winding has a start U1,V1,W1and finish U2,V2,W2 mix them up and your in trouble. Normal practice is to bring the start out of the motor together and finish out together.
I had a motor come back from being “rewound” and one set of windings was mislabelled. U1 & U2 were backward. This caused the motor to draw about 185% of full load current. The motor ran slow and erratic with no load. I found the winding that was backward and relabelled it and tried it again and it only drew less than 40% of FLA with no load on the motor. Finding the three windings is the first step, then you have to find which ends are U, V & W 1 and which are U V & W 2 because when they are wired up they form a phaser diagram for current. Each should be 120 degrees apart. If a winding is backward, one current will be between the other two on the short angle. Let’s say all windings are okay and the currents are 100 A at 0 degrees and the second is 100 A at -120 degrees and the third is 100 A at +120 degrees. If the third winding was wired backward because it was mislabelled, then the currents would be: 100 A at 0 degrees and the second is 100 A at -120 degrees and the third is 100 A at -60 degrees(+120 degrees - 180 degrees). If you plot them you will see why the current is so much higher at no load. If it was a perfect motor, the current would be 200%. If this still doesn’t make sense, plot the voltages and currents in each winding on a phaser diagram and reverse one winding and do the plot again to see the effect when you add the currents.
thank you so much... this is a very helpful video.
Thank you and yes that meter is awesome 👌🏾
very helpful thank you !
Excellent video, thank you so much!!
Thanks for your training.If you are talking about industry,you are talking about motors.
Good informations !!!Thanks for share!!!!
Another excellent vid from Sir Kitcher
This gentleman speaks like Magneto in X-Men. Nice British accent 👌
Great video, very concise and clear. I'm trying to run a three phase motor on single phase. Do you have any advice for a formula to determine capacitor size for optimum power and minimum heating? Thank you
crystal clear and super informative
you have nice digital ohmmeter.
where did you get that meter it's good that it megers the insulation
Be back but sleep called----finish it tomorrow. Great video so far.
Good video, but would have like to have seen you phase out the windings for Start and finish or 1 & 2 of each winding...before connecting in star and saying it would run correctly. Good chance a winding is in opposition to the other 2.
thank you. this is perfect explanation. on my way to test a 3 phase, dual motor, compressor. its popping the beaker every couple of hours or so. I wanted to get a quick refresher. came to the shop to pickup the fluke scope, clamp and my old all-test. Usually i work on single phase stuff. when it gets to 3ph, mainly cuz I get to use my tools I get a little jittery and excited about it, hehehehe
can polarization test be used on a single phase motor as well?
Love that multimeter
its megger not just a multimeter
Great video. Can I ask if you have a video or how you test Single phase motor. Sorry if its a silly question
powerful explanations...thank you
thank you ,so useful video
Clear and concise, thanks
phone
The large 3 phase motors I've come across are wired with the coils not aligned on the terminal block i.e W1-U2, V1-W2, U1-V2. This means you can wire them star or delta by moving the copper jumpers. Why would you wire this motor W1-W2, V1-V2, U1-U2? Is it not made to run in delta configuration? Wouldn't it be safer to wire it W1-U2, V1-W2, U1-V2 in case someone wires it into delta; to prevent a short circuit?
Yeah, I think it should be wire as what you said, U1-W2, V1-U2, W1-V2, so that easier for us to change the copper plate with vertical or horizontal directly for both Delta or Star connection respectively. But for Star Connection in this video, maybe he just don't care about that since it's for Star only, of course for safety consent, it should be like what you said.
MrCT2012 c
the video is very helpful and easily understandable,
Good Information Thanks
what about voltage applied for insulation test 480 acv 13.8acv
the successful way to get a big fire
You would never set the six ends in this configuration. The top set would be moved one place to the right so vertical delta links didn't link both ends of the same winding. ( I know this was star but you just don't do that). Also should have explained that the ones and twos must be at the correct end. Instant burnt out motor if not. Without manufacturer data you can only assume that all 3 ends from one side are ones and all 3 from other end are twos. Also you don't run 6 ends back to the starter unless it's star delta. You did say for delta. You also said contractors change from delta to star, this would be the other way round in star delta situation.
The order for terminal posts could be / top row , W1/U1/V1, bottom row U2/V2/W2. So giving two different winding ends to each vertical pair. ie. (w1/U2) ( U1/V2) (V1/W2).
I know there is a lot of good info here but there is also a fair bit of confused info here that will baffle learners.
Thanks very much for correcting stuff here. There was a lot of unanswered questions including the ones and twos which i still need more info on
Made perfectly sense.
I picked up on all of these and I don’t understand why he is using cable instead of the normal plates! Also got me confused when he said that you must run back to a contractor for delta??
Also even if your motor is on a inverter you still need the 1s and the 2s the right way round
I was thinking the same thing, i.e., how to know which ones are 1's and 2's so to speak.
quickly realized the wiring after he made the connection and immediately look on the comments to check if anyone noticed that too.
Very nice video...
Sir..
Very good explanation and video ❤❤❤
Hi there, I have recently discovered your excellent videos. I am just starting out in electrical maintenance. Could you recommend a good multimeter and megger. Also any other recommendations for testing equipment..... Many thanks
multimeter = sanwa , megger tester = kyoritsu
Yes. Pick a different field of work. 20 years from now you’ll be wondering how the hell you thought this shit would be cool to do for a living. Hot factories, grease monkey, product in every crevice of your body. Did I mention it’s hot! Shirt soaked every night. If you are lucky you will have a boss who won’t make you do project work while also running the floor fixing breakdowns. Emergency breakdowns are the worst. If there is an oven or many ovens in the plant - run! And don’t look back. Shoot! What the hell was i thinking!!!?
Really nice video. Please how do I know u1, u2, v1, v2, w1, w2? The issue here is the 1s and 2s. How do I know a 1 and a 2? Thanks.
See my comment above. Its called phasing out and using the visual effect of Lenz's Law...Using a 6 volt battery and a anologe volt meter on 10 volt or less.
Thank you for the video kind sir.
very good explanation.. but you mixed the start and the end of the coil in the terminal block. you just shorted..the wrong ends of the coil..
i like this
The insulation quality test required for each lead? I'm think yes .
How much the resistance consider that motor is damage??
Do they have to be in that order? Like w1at the top w2 beneath etc
Creative video, thanks :)
Hello sir my dear new friend very good information..watching from philippines.👇👇👇👇👇👇🤝🙏🏼
You didn’t check the polarity of the windings and the orientation to see if the motor runs clockwise or anti-clockwise.
Bet he had a reverse pole too 🤣
Very nice explanation thanks but after megger y u not short the leads to earth
wonderful
whats ment by a good "earth"? is it the same as a "ground"?
Finally , the penny dropped , thanking you kindly ! 🙏🏻
nice
does a 3 phase star motor need earthing? if so where?..what about neutral?
How much maximum value that winding at limit resistance? 1000 m ohm?
WRONG!
1st. You should look at the terminal board, it should read U1, V1, W1, V2, W2, U2, not important in star only.
2nd. What is difficult with 6 wires like that is to figure out which one is 1 and which one is 2 that have to be correct in both star and delta.
3rd. On motors with light load there is no need for a star delta starter (they are becoming obsolete because there is many better ways to start a motor today), and you can start the motor in delta with a VFD
4th. Even when you use a star delta starter it's nice to connect L1, L2 L3 on both top and bottom terminals
How to check which one is 1 and 2?
Angelinna Smith helooo
Angelinna Smith u r right
if u run it on two voltages it has to be connected for delta for the lower voltage. then it is very important to know which one is 2 or v1
what is the name of the device his using to measure the resistance and polarization of the Motor efficiency ?
That terminal block is going to going bang if someone ran delta links. The Windings should be offset on the block not aligned with each other. IE if you connect three phases then each end of a link will connect 2 ends of A DIFFERENT winding. Its dangerous to connect a winding block to only accept star links where as offsetting the windings allows for either star or delta by just changing link configuration.
PRO TIP: Set the video speed to x1.5 so the video takes 7.5 min.
You're welcome.
If he had his coffee that wouldn't be necessary.
Lol yes the speed of CZcams.
i actually enjoyed the pace
Why did you do the test with 500V ? Can we make it with 1000v ? And if it can be done with 1000v will we expect the same value after deviding the 10min and 1min ?
Hi, thank you for such nice video. Whats your multitester model by the way?
Thanks Chris
ON SOME MOTORS THE WINDING DESIGNATORS ARE MISSING..SO WHAT HE IS DOING IS CORRECT.
Furthermore, it is always best to know a complete method as opposed to relying on labels so this is a more useful methodology than is simply assuming designations are correct ad nausea
Many thanks
niceeee
what meter is that please?
at 9:30 you said that the polarization currents runs through the insulation because it could find paths through the un-aligned dipoles, but this is not accurate. The polarization current exists because of the time changing polarization density which induces the current. J = delta(P)/delta(t).
What should be the range of accurate resistance values for eleçtrical 3 phase motors
Is 3 phase 5 wire is useful?
What tester brand are you using
In terms of U, V, and W wiring assignments, did you do that randomly? How did you know which letters to give to which wires? Is it a standard configuration ?
L1=U L2=V L3=W
V good
Do you have to do the polarisation test on each winding? Also where abouts is the earth wire in that terminal block? or is it just to the body of the motor somewhere?
Also what about the neutral wire?
3 phase motors do not need neutral right?
Go back to school
Delta connection will not work. Also how do you know if a wiring is not swapped. I mean wether one of them will produce opposite magnetic field. Am I right?
Yes your correct, he has no way to know which wire is which end of the winding..
@Jack O'Bean also in star
hello sir,Thank you for your great videos, I’v a refrigeration compressor works and then stops for less than a minute and it’s circuit breaker cut off, when i 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
It’s either that in your system they are using your L2’s 230V to control a light or the control circuits or you are experiencing a motor that is unbalanced and you’d be expecting very low resistance on L2 due to the breaking down of windings
Ohm's law, voltage = current * resistance. If your current has gone up, your resistance has gone down. The winding would have failed insulation about 1/3 along its winding, shortening the length of the active winding, thus lowering the resistance.
If the winding draws 3 times normal current, then the motor draws 5/3 of its rated value. Circuit breakers used in motor protection take longer to trip, as to allow for the high start up current of motors.
Phase protection is to save your motor from running on two phases if one phase goes down.
How do you know which wire is U1 and U2 / V1 and V2/ W1 and W2?
They are the terminals not the wires. The wires can be connected in different combinations. UVW (1) WUV (2) are the terminals.
I have a motor I’m trying to identify the windings on, there is 12 connection, I can see there is 6 pairs. It was operating as 2 speed on the machine. I need to wire it at 2800 delta to connect a VFD, any idea how to identify which is which ?
how you assign u1 u2 , v1 v2 and w1 w2 ?
Check winding resistance
@@saiyachendra7326 OMG 6 years ago
Thanks so much! What's the HP of this motor?
the winding resistance value how do you know that you've got the right value?
What are the lowest insulation resistor you will recommend between earth and the winding?
Late answer but regulations say 1M ohm.
good video
Does the polarization on the insulation applies same way for all types of insulation?
I got a 3 phase motor i like to hook it up to a single phase vfd i know i need to set the motor for delta, and they have been paired. but my problem is there is no u v w labels does this matter can you "call them anything like you say"
One question sir can I connect six 6 lead motor in star or delta for high an low voltage as 220 or 460 three phase please let me know thanks
Do you do the 1 & 10 minute PIR test for each winding?
He connected all 3 windings together, so no. You'll just be testing all 3 at the same time.
I like to disconnect them from each other and do the test on each on though. Proves they're ok on their own.
What is the brand and model of your tester?
Megger MIT 400.
How do you know wich is uvw and wuv?
Thanks for information
In the ten minutes polarisation test what are the units known as ( G) ohms, what does G stand for? Thanks
Giga ohm
Can single-phase be turned into 3 phase power?
Hi, I can't understand why you didn't do an insulation resistance test from motor windings to earth, from the start of testing..... if there's a earth fault on the motor, why carry on.
Very help in one
Nice
all winding resistance are same how to identified u1,v1,w1
Datasheet or contacting the manufacturer company
need a moving coil ammeter
I'm from India.I'm general mechanical technician.3phase motor like 3wire I mean uvw.or ryb.star connection to connect u1-w2,v2-w3,w3-w1.,we can check amp minimum value it's coming every star connection motors condition ok.in 3connection any one less.that motor has ground.replace another motor
Elektro motor 380v u1 v1 w1
how do you make sure which one is U1 and which one is U2? because if you connect them wrongly you will end up burning the motor.
No it turn reverse
@@DipakFalane-es5ue no. If you do it wrongly it will burn the motor. One of the magnetic fields might be reverse compared to other two if you connect wrongly
What is the advantage of checking the resistance of the windings compared to checking for continuity?
Just checking for continuity across your windings will not tell you if you have a shorted winding. You have to check the actual resistance value of each winding and compare it to the others. The ohmic value should be very close across all windings.
I understand
Muziwandile Mazibuko . If you test the resistance of each winding using an accurate meter like this , you can check for damage within the coil such as a short circuit resulting in a lower resistance reading or an overheated coil due to a bad contactor will show up with this test . This kind of damage may not be apparent otherwise.
in any rate of motor doing same procedure Sir? 😊😊
Thanks boss