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resonance energy storage experiment

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LAN_403

Plasma

Thu Nov 28 2019, 11:49PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

Built a mini transformer from a 470uH choke, measuring the secondary shows 10.5DcV. Connected it up to both sides of the tank circuit showed max Volts of 5.88DcV, at 49khz, moving it up or down lowered the voltage to 1.9V. The transformer has all most doubled what I was getting with out it, but not sure what's wrong with the H bridge. The current from one wire of the secondary to the end resistor gets 2-4mA.

The transformer is about 1W at 49khz ,200mA^2*470uH.

Made another transformer and wired the primary in parrellel and wired the secondary in series, open circuit is 24V connected across the tank circuit, show 3.8V, not enough current handling, its dropping the output voltage.

Modified the H bridge, changed the pull up resistor to 210 ohms and removed the gate resistor I tested, I now get 7.9V across the tank circuit, but the output voltage of the transformer or bridge is the same, I think it supplies more current, well not waste it with the quicker turn on/off.

123809

Plasma

Sun Dec 01 2019, 12:36PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

I've got 3 transformer which when the secondary were wired produced 7V out of 10. Each transformer makes about 10V. Having them in series and having 4 tanks made 5.7 V on the closest tank.
Adding a 5 tank drop it to 4.5V, as I moved along the tanks the voltage dropped by 0.1V, between 4-4.5V.

The open circuit voltage is about 32V, I've ordered another 4 chokes to make another 3 , and put them one parrellel with the other 3, to see if I can get the voltage on the closest tank of 15V, which should be enough to warm up the inductor.

I removed 3 tanks ,the remain two read 10.6V. Measured across the resistors with 2.8V, given 1:3.8 ratio, I'm guessing the tanks are 3.8 Z is the power lost to ESR . this is with 4 transformers with the secondary 2 series 2 parrellel.

The Q seems to workout to 14.6/3.8 = 3.8

012517

Plasma

Thu Dec 05 2019, 09:12PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

I brought a 12V 2.5A power supply, it increased the power raising the voltage. I'm testing a third stage with a little nickelchrome wire on the inductor leg, it warms up a little with 11V across the tanks. When the wire is properly connected the voltage drops across all the tanks, looks like its at resonance.
Be interesting to see how much heat it can make. Brought two more transfers but no matter the series parrellel combination it doesn't go above 11V for 3 tanks, 2 tanks is about 14V.

100125

Plasma

Fri Dec 06 2019, 05:57AM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

The bridge had a failed open P fet, replaced it and are now getting 15V on the bridge leads.
I connected it directly without the transformers and the first 1 ohm resistor gets warm, with 3 tanks the nickelchrome warms slightly, having 1 tank, the nickelchrome gets to hot to touch., across the tanks is 6V with 3 .
There's 3ohm of resistor to the last tank making possible 2A.
Had to adjust the frequency ossiclator which someone hinted at, by removing the 1.2k fixed and just having the 5k pot, it makes it go from 2Mhz to 36khz.

At 50khz the line current was 1.2A measured on DC from the supply positive rail. If it devided equally between 3 tanks 0.4A.
Looking on wiki Nichrome page 28Awg at 204Â°C =1.18A
316Â°C = 1.55A
Guessing 100Â°C =0.81A and 50Â°C = 0.62A.
Out of the Line current there's the gate with 200mA and about 100mA for the Schmitt.

The 3 tanks from the furest is 25Â°C 0.44A, 50Â°C 0.62A , 100Â°C 0.81.
Its about 1.87A, the 1.2A line current was the max value, but the range from 0.2A to that. The Nickelchrome wire is 27ohms/meter the distance is 40mm

Just savings up for a 24V bridge, it will be pretty much the same design as this one.

Plasma

Sun Dec 08 2019, 09:28PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

Wired up the below picture, the line current went up to 2.45A with 9.2V across the tanks. I added a filter cap to the bridge, and are running the oss and bridge on different power supply. Changed the Nickelchrome wire from 40mm to 20mm it drawed more line current, I think because the tanks are a sharper resonance. Stabilized the voltage and current but the frequency jumps +-2kV. At 100Â°C the 28Awg is 0.81 *4 3.24A.
The open circuit voltage was 15V. I think if I get a 24V 1.25A supply, it would regulated the current, but the wire should be the same temperature has 12V 2.5A.

101819

Plasma

Mon Dec 09 2019, 10:33PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

Found a chart for Nichrome that relates colour to temperature. Having just 2 they glow slightly red, probably just 500Â°C

I measured the current with the probes either side of the Nickelchrome wire, I think its about 1ohm with the DMM about 1ohm internal. The reading was 0.6A which makes 1.2A, times two tanks would explain the 2.45A line current.
When lowering the frequency below resonance it doesn't have to go far to drop to zero current.

QVTF6

Plasma

Tue Dec 17 2019, 07:36AM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

Modified the test bridge, I've got the P MOSFETs on there own channel, and are driving the lower FETs directly from the oss. At 50khz it draws 1.3A with 18.8V across the tank. Across the Nichrome wire I get 0.29A.
Having this bridge setup seems to work better, I've still got one pull up resistor, but next week when I get the 24V supply will add another 212ohms. Funny thing the bridge open circuit shows 40V, I don't understand how it got that high.
The 50khz set on the pot is about 1/3rd compared to posts early, also just arrived is new parts to make the oss and bridge, will just do some more mucking around with the first prototype.

Plasma

Fri Dec 20 2019, 08:17PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

Tested with 24V supply. I get 26.8V across the tank and 9.1V across the wire, if the wire is 1 ohm it makes the inductor 3 ohms at 50khz. The reactance at 50khz is 14ohm, with two tanks in parrellel leaving 7 ohm.
The wire got hotter than 12V supply when the 12V supply was working probly.
The line current is 1.3A at 50khz but decrease to 0.7A around 130khz?
The voltage are probably off by they will all be off the same amount, getting 69V open circuit if that's peak to peak times 1.8?

Changed one tank from 47uH and 220nF to 470uH and 22nF. The voltage across the tank was 49.2V ,across the wire 7.7V making 6 ohms, the other one the original 49.4V and 17.5V. Making 3 ohms.
The original wire heated up a lot more as more power got divided to it. Its a juggle at the moment between line current and through the inductor.
Line current 0.82A

With two tanks the larger inpendence I measure 94.5V across the tank and 0.75 line current, the wire is just warm.

25V supply / 36(6*6) = 0.69(0.75 - 0.056 gat) line current.
25V supply / 6= 4.1A circulation current

090428

Plasma

Tue Dec 24 2019, 02:39AM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
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Posts: 268

The current from the supply is 0.275A, the tank 92.2V and wire 23V , makes 4 ohm, with two tanks 0.113mA making 440mV.
Tested with 36V 79.6V and 16V with 1.2A line current, I'm guessing but the bridge is fried, the wires are hotter, but with the line current been more, will test tomorrow.
The supply was shorting the oss, when separate the line current was 0.65A at its lowest, lowering the frequency to 48khz the wire was to hot to touch, I should be able to test 48V supply when I get another adaptor, but one of the MOSFET gets quite hot after awhile.

Put a third tank on, the supply current went up to 0.807A with the wire dropping a little in temperature.
Having the third tank made strange results, one MOSFET got hot, when put back to two was normal again, but with three the wires were roosting. I think some strange resonance thing was happen as I've had 2.45A through the bridge and it didn't get that hot.

Just spec out 68V 3A supply from two 24Vac transformer and ripple caps.

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