Thane Heins BI-TOROID TRANSFORMER

[ramset]

Tak
Thanks for keeping us up to speed on the "Crankster"!!
I like the idea of Non stop ....................
I think it will catch on??

Chet

[Jack Noskills]

This is continuance from discussion started from gabriel thread, started from page 38. Brolis 3d picture of the transformer under test attached.

As I dont have amp meter available I decided to do a comparison test instead, it should give some clue. One more identical coil in the middle so system can work like a normal transformer at the same time. My load side was using 350 watt electric saw.

40 watt light bulb on the primary side
normal trafo: I press start button in the saw, primary side bulb lits to almost full brightness but the blade does not move at all.
modded trafo: Blade does not move, light is dimmer compared to normal trafo.

Next I add 25 watt light bulb in primary side, I keep the saw button pressed.
normal trafo: The 40 watt light dimms little as the 25 watt light up. The total power on the primary side is thus less than 65 watts. Blade moves maybe 1 mm per second.
modded trafo: First lights glow brighter (still fainter compared to normal trafo). I wait the blade to gain full speed and as the speed increases lights go dimmer. Blade moves now faster and it can actually cut 8 mm plywood, slowly though. I can still see the lights dimmly, I would estimate it has about the same brightness as without load.

Another 25 watt bulb in the primary.
normal trafo: Same effect on the lights, they dimm a little more as the third light lits. Now blade moves faster but cannot really cut the wood piece, it jams almost immediately. Both the primary and secondary coil warm up, I would say to same temperature. If I jam the blade there is no effect on the lights.
modded trafo: Again I wait for the blade to speed up. At full speed I can barely see the lights, a mild glow only. Wood is cut nicely but if I press too hard the blade slows down. As the blade slows down the lights go brighter. Both secondary coils get warmer than the primary coil. There is hardly any current going in the primary but it still gets warm. My conclusion is that it gets aiding flux from secondaries or BEMF from the motor gets recycled.

Lastly 40 watt bulb added.
normal trafo: Again rest of lights dimm as new one is added. Now the blade can cut wood and it seems to have equal power compared to modded trafo at this level.
modded trafo: All lights are dead, not even a faint glow visible. Blade runs faster and does not jam anymore. Finally I changed one light bulb to a 1 watt led light bulb to see better how much power might go through primary. When the saw was running at full speed, the 1 watt bulb was not at full brightness, maybe at 50 %. So I was using atmost maybe 4 * 0.5 watts in primary side and getting maybe 60 - 80 watts out, assuming all lights got the same amount of power.

I might get a nice COP figure out of this but I am not interested in exact values as this is too low power. But it clearly shows this design has some potential in it and with bigger cores and thicker coils more power could be possible to get from this quite easily.

Lastly, note that there are no air gaps, not intentionally anyway. I tried one version with 1 mm air gap between two cores but I got less power out. Did not test air gap in the primary coe side. I would say it makes things worse in this design.

This is enough of this from me for now. I hope this shows enough potential so someone makes a replication using better materials, play with permeability difference between cores, use maybe two secondary cores on both sides etc. If you can make a working version, would be nice if you report your findings here, what ever they are.

[broli]

This is continuance from discussion started from gabriel thread, started from page 38. Brolis 3d picture of the transformer under test attached.

As I dont have amp meter available I decided to do a comparison test instead, it should give some clue. One more identical coil in the middle so system can work like a normal transformer at the same time. My load side was using 350 watt electric saw.

40 watt light bulb on the primary side
normal trafo: I press start button in the saw, primary side bulb lits to almost full brightness but the blade does not move at all.
modded trafo: Blade does not move, light is dimmer compared to normal trafo.

Next I add 25 watt light bulb in primary side, I keep the saw button pressed.
normal trafo: The 40 watt light dimms little as the 25 watt light up. The total power on the primary side is thus less than 65 watts. Blade moves maybe 1 mm per second.
modded trafo: First lights glow brighter (still fainter compared to normal trafo). I wait the blade to gain full speed and as the speed increases lights go dimmer. Blade moves now faster and it can actually cut 8 mm plywood, slowly though. I can still see the lights dimmly, I would estimate it has about the same brightness as without load.

Another 25 watt bulb in the primary.
normal trafo: Same effect on the lights, they dimm a little more as the third light lits. Now blade moves faster but cannot really cut the wood piece, it jams almost immediately. Both the primary and secondary coil warm up, I would say to same temperature. If I jam the blade there is no effect on the lights.
modded trafo: Again I wait for the blade to speed up. At full speed I can barely see the lights, a mild glow only. Wood is cut nicely but if I press too hard the blade slows down. As the blade slows down the lights go brighter. Both secondary coils get warmer than the primary coil. There is hardly any current going in the primary but it still gets warm. My conclusion is that it gets aiding flux from secondaries or BEMF from the motor gets recycled.

Lastly 40 watt bulb added.
normal trafo: Again rest of lights dimm as new one is added. Now the blade can cut wood and it seems to have equal power compared to modded trafo at this level.
modded trafo: All lights are dead, not even a faint glow visible. Blade runs faster and does not jam anymore. Finally I changed one light bulb to a 1 watt led light bulb to see better how much power might go through primary. When the saw was running at full speed, the 1 watt bulb was not at full brightness, maybe at 50 %. So I was using atmost maybe 4 * 0.5 watts in primary side and getting maybe 60 - 80 watts out, assuming all lights got the same amount of power.

I might get a nice COP figure out of this but I am not interested in exact values as this is too low power. But it clearly shows this design has some potential in it and with bigger cores and thicker coils more power could be possible to get from this quite easily.

Lastly, note that there are no air gaps, not intentionally anyway. I tried one version with 1 mm air gap between two cores but I got less power out. Did not test air gap in the primary coe side. I would say it makes things worse in this design.

This is enough of this from me for now. I hope this shows enough potential so someone makes a replication using better materials, play with permeability difference between cores, use maybe two secondary cores on both sides etc. If you can make a working version, would be nice if you report your findings here, what ever they are.

I was wondering, do you still have the setup laying around?

[Jack Noskills]

Sure, I am not trashing it until I figure something else to test.

[broli]

Sure, I am not trashing it until I figure something else to test.

That's  good, I would even go further and suggest after you're done playing  with it, send it to a thrust worthy member on the forum who has a DSO, equipement and skills to analyze it and extract the exact numbers.

Perhaps it would be also usefull for people to suggest places where the cores could be bought for a reasonable price in the US and Europe. I would say for the primary core one could use a 3 phase transformer core (not cheap) but usually the 3 legs on that have the same width, I don't know if that's important or not.