47000 Watt Magnetizer

[MileHigh]

Yes,you have marked the field lines for the center position of the magnet in relation to the core of the coil-->but what about the field lines when only one pole of the magnet is under the core?(the center picture)

Either orientation you will get EMF induced in the pickup coils but it looks pretty obvious that a radial magnetization pattern would induce more EMF in the piclup coils.  Either way, this whole Jim Murray business is peseudoscience junk.

[DreamThinkBuild]

Hi Carroll,

Sorry, I haven't tested which angle is best. I calculated the maximum angle for my current setup to be 30 degrees to keep it within the core right to the edge, 6 degrees to be completely in the core and 12.5 degrees to have the core cross the center line of the magnet.

My lab is ripped apart awaiting new desk/shelves so once things are setup again I can test between those angles to see which one has the best output.

I did a quick sim and it looks like keeping the highest angle right near the edge has the most flux through the core. Real testing usually reveals where the problem spots occur.

edit: Added zip file with animation, forgot gif won't work here.

[tinman]

A short update on the magnetizer.
1.4 kW's charge power

https://www.youtube.com/watch?v=TPNLjxRf_GI

[tinman]

Well i got the pot magnetizer finished,but it will only magnetize steel/iron items very weakly.
Below is a scope shot of one single pulse,and i managed to get the pulse duration down to around 35mS. The start of the pulse is very erratic-->would this be due to the arcing across the solenoid contact's?. It also looks like the solenoid cannot handle the current,as i am supplying the unit with 48 volts,but it seems to drop off once the relay has closed properly. I know it's not the battery voltage dropping down,as that remains at 48 volts before the relay,and the cables are 12mm multi strand.


Brad

[gyulasun]

Hi Brad,

Yes, I also think the erratic start of the pulse can be caused by the arching across the solenoid contacts, looks like flyback pulses due to current interruptions.  You have surely checked and improved the contacts since then?
The voltage drop may still be caused by resistive loss as was the case initially for Luc's setup, when dealing with peak currents of several Ampers or some tens of Ampers , every milliOhm counts.

I think it would still be worth checking the voltage drop across the battery by your oscilloscope during the ON time, due to the 24 cells in series,  the inner resistances add up.
Just considering say 0.01 Ohm for a single cell,  24*0.01=0.24 Ohm and when you have a 10 Amper peak current at the switch-on moment, the drop is 2.4V. You seem to have a 23-24V drop from the start battery voltage...  as if you had a 100 Amper peak current at switch-on? (assuming the total 0.24 Ohm resistance in the circuit). I do not know the resitance of the solenoid.   
A quick test: connect a high uF capacitor across the battery bank and see whether the drop reduces.

Gyula