3 phase motor test

[wiserdaley]

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.

[laworder]

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.

[michealplater]

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.

[berkotropia]

You always bring light into my brain! Thanks for that! The people who work with you are probably the luckiest people in UK

[gibbyrockerhunter]

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!

[reissner]

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.

[matthewmeuleman]

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.

[pedrooropeza]

Thank you for the information I like the way you explain the work

[wiserdaley]

This gentleman speaks like Magneto in X-Men. Nice British accent 👌

[simonevans]

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.

[bradjunes]

Be back but sleep called----finish it tomorrow. Great video so far.

[vincentmasanja]

Thanks for your training.If you are talking about industry, you are talking about motors.

[tonyfrewin]

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.

[vourill]

Great lecture...but the way the leads are terminated at the terminal block it will be difficult to delta the connection at the terminal block!

[chriskitcher]

It is a Megger MIT 400.  Very good piece of equipment

[yoshdon]

Another excellent vid from Sir Kitcher

[lucyhaule]

the video is very helpful and easily understandable,

[paintballisawsome]

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.

[angelinnasmith]

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

[replicant]

Finally, the penny dropped, thanking you kindly ! 🙏🏻