Confirming the Delayed Lenz Effect

[Mk1]

"@all


Hi , i know that one i used to have a pdf copy of a old book called AC electromagnet , and it could pick up any thing plastic you name it .

I will see it i could find it again i tried before without succes.

Mark

[hoptoad]

It's very interesting I agree. I think an electromagnet can be AC and still attract ferrous metals but the attraction would not be continuous. Not sure.

Anyway I have some idea's for experiments. Any results I get that seem interesting I might post in a more relevant thread.

Cheers

I vaguely remember an AC electromagnet discussion in tech school many (very many LOL) years ago. However it was not really an AC electromagnet, though it was referred to as one.

Instead, the coil comprised a bifilar winding with each winding connected in parrallel but with a diode connected in singular series with each single winding, in opposite conducting directions. The coils polarities were such that each half phase of the AC supply produces a net unidirectional magnetic polarity, mimicking that of a single coil connected to dc. There is however a pulse ripple associated with each half wave of the supply, resulting in a varying magnetic strength (oscillation) similar to pulsed dc.

Cheers

[ALVARO_CS]

Check out this amazing pulse motor!

http://www.youtube.com/watch?v=zsmehZrqsPM

MileHigh
thank you for this sophisticated piece of technological experiment, could not stop laughing for a good half  an hour !!
cheers

[hoptoad]

MileHigh
thank you for this sophisticated piece of technological experiment, could not stop laughing for a good half  an hour !!
cheers

Me Too !

[gyulasun]

Hi Folks,

Synchro1 and Magluvin objected the series connection of the two coils to be compared so I repeated the tests separately.
OF course I used 0.75 V DC voltage from my variable supply to have about 430 mA DC current into any one of the (separated) coils, I used the same coils as yesterday. (DC resistance for both is 1.6 Ohm.)
(Synchro1 also objected that the two bolts were too close to each other so they influenced magnetically each other. Well, as I held them in my hand I did not feel any such interaction (nor attraction, nor repulsion). IF these electromagnets had the force of an equivalent Neo cylinder magnet I surely was not able to keep them in my palm like that, they would either jump away or snap together for sure. What I felt was as if they were weak BaFe ceramic magnets.)

This time I used small nuts as objects to be lifted because I thought they fit here better than paper clips for picking them up. I sorted out 50 - 50 nuts to make two separate groups, 50 for the single and 50 for the bifilar coil tests.
I started with the single wire coil, I pushed the head of the single wire bolt into the pile of 50 nuts, switched on the supply (430mA) and slowly lifted up the bolt and moved to a clear area to separate the nuts from the pile and count how many were lifted. I repeated this till all the 50 nuts were used up from that pile.
Then I did the same test with the bifilar wire electromagnet, using the other pile of 50 nuts.  Here are the results:

Single wire coil test        Bifilar wire coil test

first lift     11 nuts                   12 nuts
second lift  8 nuts                     9 nuts
third lift    13 nuts                    11 nuts
fourth lift    9 nuts                    10 nuts
fifth lift        9 nuts                     8 nuts

This shows the performance of the two electromagnets practically the same.

Gyula