Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated

[listener191]

It depends how far you would like to go on heating coil wires.

In Pierre's setup the input was 110V 1.5A which translates to 165W in total and supercaps was on 20V charge. Which translates to 8.25A consumption in total across all coils minus BEMF recovery.
And for a sake of test how much you can get from artificially created rotating magnetic field it does not need to consume so much power.

Cheers!

Hi T-1000

There are three current paths, so each high side and low side switch would be conducting 2.75A based on the assumption that all of the power is coming from the supply, which is well within a paralleled L298N's rating.

Pierre alluded to a much larger current per switch pair (not stated though), so perhaps the recovery is much higher than we can see at this time and hence the coil current is higher.
If he could give us a ball park coil current, that would be helpful in a number of ways.

Regards

L192

[seaad]

Builders You need a gross value of 900 Watt to make your magnetic field,  if you don't find a method to recover power to the electromagets!

And Pierres OU

Regards Arne

[listener191]

Builders You need a gross value of 900 Watt to make your magnetic field,  if you don't find a method to recover power to the electromagets!

And Pierres OU

Regards Arne

Hi Seead,

At such a low clock frequency DC resistance dominates so...

6 of my coils in series are about 6.41ohms, so two of these series chains are fed in parallel, so 3.205ohms  .. 21V/3.205ohms = 6.55A  x 3 paths = 19.65A,  closer to 412W.

Regards
L192   

[onielsen]

To prevent melting the insulation or the wires stay below 2000A/in² = 3.1A/mm². Source of this information:
http://what-when-how.com/electric-motors/current-density-electric-motors/
Here are more on designing stator windings:
http://what-when-how.com/electric-motors/design-equations-electric-motors/

There has to be enough inductance in the coils to limit the current at the frequency used. If using resistance to limit the current place external resistors rated for dissipating the required amount of power. This of course is a total waste of power. External inductors can also limit the current. Inductors don't dissipate the power as the energy is given back at demagnetization. Better design the windings for the job without dissipating power as heat.

Regards
Ole

[Jeg]

IRF3205 / IRF4905

Max values
55V, 200W, continuous Id=52A/80A, Pulsed I=260A/390,  Rds(on)  8mOhm/20mOm

An interesting mosfet matching and cheap. With a capable heatsink it will run fine

http://www.irf.com/product-info/datasheets/data/irf3205.pdf
https://www.infineon.com/dgdl/irf4905.pdf?fileId=5546d462533600a4015355e32165197c

As for clamping diodes i was thinking about UF5408. 1000V/3A. Any other idea here?