TTT349 Inductor and Transformer Testing

Рет қаралды 3,703

tomtektest

Күн бұрын

Equipment and methods for testing inductors and transformers.

Пікірлер: 29

@martinlucero9594 3 жыл бұрын

Don't stop giving all the world all your knowledge..! Greetings from Argentina!!

@gwolf8807 Жыл бұрын

Many thanks from Bulgaria!

@larrysmall3521 3 жыл бұрын

Very well done. A good combination of review and new material for me. I became aware of leakage inductance when an engineer I worked with went through some switch mode power supply design concepts with me. If I remember correctly he actually increased the leakage inductance by having a slight gap in the core. He did this to help reduce core saturation at full load output.

@tomtektest8042 3 жыл бұрын

You are very well informed on the importance of using leakage inductance to prevent core saturation. I am going to be doing some more on Power Electronics and DC-DC Converters and, as I think you already know, Leakage Inductance in Flyback Converters can allow a design to operate over a wider range of load and/or supply conditions without the core of the flyback transformer becoming saturated. I am not sure whether I will go into that in much depth but I will try to mention it in a future video.

@tomtektest8042 3 жыл бұрын

You might want to read the material in Chapter 13 Section 8 (iii) of the Radiotron Designer's Handbook by Langford-Smith and Reference E28 on the importance of controlling leakage inductance in the McIntosh Amplifier. You can download a pdf version of the book at WorldRadioHistory.com website.

@mlkegates5857 2 жыл бұрын

This is a great instructional video. Thank you Tom. I have a question about the test leads on the DE 5000 but I'll look back to see if you have already addressed it.

@Jnglfvr Жыл бұрын

When the secondary is shorted the resultant primary inductance is the sum of both the primary and secondary leakage inductance referred to the primary. When the primary is shorted the inductance of the secondary reflects the sum of both the primary and secondary leakage inductance referred to the secondary. If N1 and N2 are primary and secondary turns and X1 is the leakage reactance referred to the primary then (N2/N1)^2*X1 is the leakage reactance referred to the secondary. Similarly if X2 is secondary leakage reactance then (N1/N2)^2*X2 is the leakage reactance referred to the primary. Since inductance and reactance are linearly related (as you noted) the same applies to the inductance. In the example at 22:33 since N1/N2 = 4.13 one would expect that the leakage reactance in winding 1 (42.3) would be 4.13^2*2.5 = 42.6 which is very close to the measured value of 42.3.

@washerdryeradvicechannel8041 2 жыл бұрын

I missed your videos. I hape you are doing well Tom

@gregorythomas333 3 жыл бұрын

I'm glad I had my coffee already...doing math on an early Sunday morning would have been pretty ugly without it! :)

@davidt7317 3 жыл бұрын

A very interesting video. Keep on producing them please. I learned a lot.

@Yorumcu63 3 жыл бұрын

Great video Thank you very much for this great details

@g1ld 3 жыл бұрын

Great video!

@bobflyer4346 3 жыл бұрын

Nice and clear presentation...Thanks

@pbaemedan 3 жыл бұрын

Professor Tom, thank you for your great videos. They are easy to understand and very practical, have you considered writing a book? Also Sir, Merry Christmas and a Happy New Year to you and your family. Maybe in 2021 you can have a practical video on the use off Bridge circuits. I find bridge circuits very useful. Thank you, Danny KI6VBC

@clytle374 3 жыл бұрын

Thank you

@jdmccorful 3 жыл бұрын

Good food for thought.

@allthegearnoidea6752 Жыл бұрын

Hello Tom isnt the paper shim found within an output transformer designed to increase the leakage inductance? I’m guessing is increases the bandwidth by lowering the Q

@acdcjustthebest....8980 Жыл бұрын

Hi Tom, Great video. Hopefully you maybe able to advise me with a problem I am having. I have counted off all the windings on a vintage radio power transformer of reasonable size and weight that used to be 240/365 c.t 60ma plus filaments. 1st attempt I rewound Primaries like for like but instead of the 365v c.t I calculated for 140v and a separate 28v. Fitted the Laminations back and tested. Voltages are perfect but the windings are heating up to 80deg C with in 10 minutes. So I added 460 extra primaries to make (1612) and calculated the 140v and 28v again and I measured 200ma no load and it heated to 100 degs C over about 10mins and it’s 10 degs C here at the moment. The windings are all new copper and wound perfectly with high temp tap in between layers. Would you have any idea what could be causing the issue. Cheers J…. I rewind vintage radio Trannys like for like and never have a problem.

@TB-jl9fr 10 ай бұрын

How thick is your used wire? How did you do the windings? What is the frequency?

@acdcjustthebest....8980 10 ай бұрын

That was sometime back now, I have sorted the heat problem. It was a mistake I made with the shielding between the primaries and secondaries. I made a computer guided winding machine that is very accurate and works with G codes. A standard vintage radio at 240v is 50Hz.

@richardgray8593 3 жыл бұрын

This leakage inductance concept and measurement is new to me, but then I didn't go to what could be considered a top-tier engineering school.

@tomtektest8042 3 жыл бұрын

Actually I think I went to what is regarded as a top-tier school and never even heard about leakage inductance. Instead, it was back when I began reading papers and articles on audio output transformers in the 60's that I became aware of the need to measure and consider leakage inductance. I think the first time I heard of leakage inductance was in a paper written by engineers at McIntosh explaining why they had to re-design their amplifiers and output transformers, taking leakage inductance into account, to reduce distortion caused by crossover in push-pull output stages. The paper was published in the 60's but it referred to work from the 30's. I mentioned this in a previous video (I think it was one of the "Magazines" videos but I cannot remember specifically) at any rate, a search of the internet reveals many articles on it including one by Voltech that has many useful figures.

@richardgray8593 3 жыл бұрын

@@tomtektest8042 That makes me feel a little better. I went to a top-tier college football school, but since I was not a football player, that distinction did me little good.

@tomtektest8042 3 жыл бұрын

@@richardgray8593 Yes, I found out what "Meat on the Hook" means. Good thing I was better at engineering than I was at football.

@cosmo0080 2 жыл бұрын

hi, can i test a conductor with a digital meter?

@hisheighnessthesupremebeing 3 жыл бұрын

Using the DE5000 is it possible to test a coil at a couple of different frequencies and then extrapolate out to say 200 kHz?.. Eg the output coil (low pass filter) in an type D amplifier.. Or some how graph the characteristics of coil at different frequencies other than what the tester uses

@tomtektest8042 3 жыл бұрын

The DE5000 can test at 100, 120, 1000, 10000, and 100000 Hz. As you probably already know, it is more risky to extrapolate than interpolate. So predicting performance between two measured points is more likely to be correct than predicting a point outside the measured range. Nonetheless, it is possible to do so but, where possible the extrapolated value should be confirmed by experiment.

@suniljandu3187 2 жыл бұрын

I think this is not true inductance of this transformer because if it's inductance were 665 mh,it will take above 1 amire no load current in primary side . something goes wrong.

@suniljandu3187 Жыл бұрын

Wrong explanation