My Motors got me to Tap into Radiant Energy

[iankoglin]

As I tried to explain to you before... if you connected the you circuit the way you explained here (of course I don't know if by the input of the FET you mean the gate or the drain), you should not have gotten the light to light. You need something to turn on the FET. The input of the FET is the drain and the output of the FET is the source. If you did hook it to the gate, did you try to disconnect it to see if it would turn off the bulb. You should be able to turn the bulb off and on by connecting and disconnecting the regulator. Try this and let me know.



Larry

G'Day Larry

When I say I connected the output from the Oscillator or the output from the Regulator I presume I am connecting to the input of the mosfet circuit when I connect to the Mosfet circuit Gate Bus
I actually connected to the Mosfet circuit Gate bus, when I connect the Oscillator this way No Light ON when I By pass the Oscillator by connecting the Regulator to the Mosfet circuit Gate Bus the the light comes on Bright and when I disconnect it goes Off so I am the Regulator and the Mosfet circuits are working

I have purchased of Ebay on of these

Square Wave Signal Generate Generator Module * Frequency / Duty Ratio Adjustable | eBay
it will probably take a week or 2 to get here then when I connect it Up everything will work fine or perhaps

Regards



Still working at it

[larryross]

For all you brave pioneers in opto matters:
Corrected circuit for high side drivers:

• DC/DC converter -> pin 1/2 now correct
• Protection diodes added -> D1/2 shall be of of low capacitance type . Normal 1N4007 will do for lower frequencies.

@Larry: What was your idea of inserting protecting diodes?

External diode parallel with FET internal diode. Suggested earlier by someone else and I read in a couple of other places that it is a good idea as the internal one is barely sufficient. If you have cut the drain pin off your FET then it will be difficult to install.

[COLOR="Red"]ADVICE: Please start with low stress on your circuit: voltage, load, duty cycle, frequency. Increase stress conforming your expertise you learned from operating your circuit.

Regards
Larry

[prochiro]

JohnStone

Hi John
Do you have a secret source for the DC-DC converters. Everywhere I check has no stock or 25 min. order. Maybe a cross ref #???
Dana

[JohnStone]

For all you brave pioneers in opto matters:
Corrected circuit for high side drivers:

• DC/DC converter -> pin 1/2 now correct
• Protection diodes added -> D1/2 shall be of of low capacitance type . Normal 1N4007 will do for lower frequencies.

@Larry: What was your idea of inserting protecting diodes?

ADVICE: Please start with low stress on your circuit: voltage, load, duty cycle, frequency. Increase stress conforming your expertise you learned from operating your circuit.

[JohnStone]

....
4. Hooked up coil, and puff, I lost my dc/dc converter, on the high side, at least it got very hot, I shut it down and had to leave, so I'm not sure what has happened yet.

Hi Thug,
I am so sorry you smoked silicon because of my circuit being still under contruction. Thanks for daring to pioneer! As Larry mentioned some protection diodes might be necessary. I plan to investigate this matter by measuring the voltage spikes on all terminals with 12V and a resistor and coil in series as load. Tender approach is a MUST if you love your circuit.

@ALL: Some know how regarding increased gate resistance:
A gate can be driven via a higher gate resistance at low frequency and low load - only. The restrictions above are to be obeyed! Why?
Different from transistors our FETs make use of the whole silicon chip if full opened only (full conductive DS-channel). Below full conduction - the usable conduction channel is being tied up by the electric field of the gate (imagine a flexible hourglass being choked at the constriction area). We get a higher resistance and additionally the increased heat losses focus an the choked area only. We obsereve a multiple positive feedback! Different from transistors the conductive channel increases its resistance at increased temperature. (Different from transistors FETs are happy if operating in parallel!)
If we drive the rated DS current (IDS) and higher frequencies the FET will give smoke signs of pain! The silicon will be punched by molten areas.
Usual FETs are not built for analog operation. Special makes are available for this task where special precautons are made in order to dissipate the heat generated inside.

We learn that for initial testing with low stress in our circuit higher gate resitstance might be helpful in order to detect problematic behaviour but later on the switching action shall be as fast as possible.
The small gate resistance serves for dampening resonant oscillations between gate capacitance and inductance of the wire. Those oscillations will give poor switching property because the FET shows multiple transitions while oscillating from on to off state -> RF disturbance, losses!.
You should know that FETs are extremely fast semiconductors. Their limit in switching originates from the gate capacity and the aibility to pump electrons there to in order to generate the electric field. There are circuits out there where quite normal FETs show switching speeds in the picosecond range! This explains their inclination for HF oscillations.

Sorry, for complexity. If we leave proved and dead safe areas some conditions start to become essential!

Summed up: The low side switch seems to be proved and can be built by others but not the high side switch.

[larryross]

G'Day Larry,Thugugly
I have loaded some detailed pics in my PhotoBucker here for a clearer view

Sun 8 July 2012 pictures by Kogs1 - Photobucket

In the above pic it is the same one I used but was an old pic where I had left out 2 jumpers I had included the jumpers in the cuit under test
@ Larry
There is only one pot in my circuit in the photo at the bottom there are 2 blue wires they go to each side of the 50k pot the brown one goes to the wiper.
The green wire at the bottom is running under the board to connected to the earth bus that runs along at the top of the picture along the underside where all the earths are it connects to the regulator earth.
At the left the red wire comes from the regulator and the brown wire goes to the input of the Mosfets.

Larry If I leave this oscillator out of the Machine and remove the coil and large Diodes from the circuit and replace the CLF with an 36v bulb then connect the output from the regulator direct to the input of the mosfets the 36v bulb lights up bright

As I tried to explain to you before... if you connected the you circuit the way you explained here (of course I don't know if by the input of the FET you mean the gate or the drain), you should not have gotten the light to light. You need something to turn on the FET. The input of the FET is the drain and the output of the FET is the source. If you did hook it to the gate, did you try to disconnect it to see if it would turn off the bulb. You should be able to turn the bulb off and on by connecting and disconnecting the regulator. Try this and let me know.

Please Larry in your circuit LM339 /4 comparitor it shows R5 as 38k the only resistors I can get here are 38k3 would these be OK

Yes that resistor would work... the original resistor was 45K.

@ Thugugly
The pic above is my circuit exactly except it does not show two blue jumpers though they were in the circuit when tested . The copper wires are woven through the board to each component and where there is a line where you do not see the wire as it would connect with/crossover the other wire it actually runs under the board I have tried 3 different 555 timers

I do appreciate Your help
Regards

Regards
Larry

[larryross]

Ian I thought you said your oscillator worked except when you connected it to the FET board.

[ampsvolts]

Thanks Ian for your consideration,
Checked the link out but others beat me to it.. will keep looking
Cheers - Waiting for the next UFO installment

Found the motors in the UK at Miscellaneous components

[iankoglin]

Hi to all my US friends.. Nice to Know UFO is OK -



Any suggestions as to where I can buy a couple of these motors.. Seems that there is no shipping to international customers and I am "down under"

I would appreciate any suggestions.
Cheers
AmpsVolts

G'Day AmpsVolts
Try here
Super Speed 9-18VDC Hobby Motor | eBay

Regards

[iankoglin]

RE Pots

Ian
I see 2 pots on your circuit board. I assume the 50K pot is for the frequency adjust, but what is the other one for?

Regards
Larry

G'Day Larry,Thugugly
I have loaded some detailed pics in my PhotoBucker here for a clearer view

Sun 8 July 2012 pictures by Kogs1 - Photobucket

In the above pic it is the same one I used but was an old pic where I had left out 2 jumpers I had included the jumpers in the cuit under test
@ Larry
There is only one pot in my circuit in the photo at the bottom there are 2 blue wires they go to each side of the 50k pot the brown one goes to the wiper.
The green wire at the bottom is running under the board to connected to the earth bus that runs along at the top of the picture along the underside where all the earths are it connects to the regulator earth.
At the left the red wire comes from the regulator and the brown wire goes to the input of the Mosfets.

Larry If I leave this oscillator out of the Machine and remove the coil and large Diodes from the circuit and replace the CLF with an 36v bulb then connect the output from the regulator direct to the input of the mosfets the 36v bulb lights up bright

Please Larry in your circuit LM339 /4 comparitor it shows R5 as 38k the only resistors I can get here are 38k3 would these be OK

@ Thugugly
The pic above is my circuit exactly except it does not show two blue jumpers though they were in the circuit when tested . The copper wires are woven through the board to each component and where there is a line where you do not see the wire as it would connect with/crossover the other wire it actually runs under the board I have tried 3 different 555 timers

I do appreciate Your help
Regards

[thugugly]

Maybe we should be using a higher coil resistance to drive hi/lo. I measured the incandesent light (il) resistance (5.7 ohms), will unhook the bifilar (1.2 ohm), and use a (2.4 ohm) coil, and add (3 parallel,10 ohms resistance) to bring it up to the (il) resistance, and try once more before i go. I could at least have a few more converters for when i get home... I'm sure JohnStone or Dana it have it working by then.

I think i will use a higher gate resistance as well, 2.2 k, Larry mentioned that he thought it might need to be higher as well, I think. It worked with the homemade shifter.

But not tonight

Thug

[thugugly]

@thug & All

I tried the high-low side driven switch like that and had similar problems. Smoked some silicone too
In the driver's datasheet there info on suppressing negative transients when hard switching inductive loads by adding more resistance to the gate lead. Eventually I abandoned that config and I am working with low side only MOSFETs and IGBTs with low RdsON and high dv/dt
Tesla did abrupt switching with spark gap and mercury type low resistance commutators and others confirm that the BEMF effect is most powerful when the time to turn on/off the transistor approaches 0!

kEhYo

Thanks for tip kEhYo77, This is same behavior I got when I tried the ir2101, thought I would give it one last try with opto's, still have a few left, and two dc/dc converters, so I'm not quite done yet, Go JohnStone Go.

So far the best hi/lo driver was the homemade n-fet, driving the hi pfets, it worked for 24 v, vnice, but i can't get these factory drivers to switch 24v without frying something.

BTW, Nice setup.

I would love to know more about your shorting technique, you should start another thread, sounds really interesting.

Peace

Thug

[thugugly]

ok john,

Here's a video of the small light, hi/lo, before I tried coil.

Pictures by Thugugly - Photobucket.

I know this is not much but it's as far as I have gone. The cap across the 8-5 pin of opto was .1uf/50v.

I hoped it would work, as I won't be home for 1-2 weeks, I can't wait till I'm back, i'm sure john you will have it working, and I can save some money

Peace and good luck JohnStone

Thug

[kEhYo77]

@thug & All

I tried the high-low side driven switch like that and had similar problems. Smoked some silicone too
In the driver's datasheet there info on suppressing negative transients when hard switching inductive loads by adding more resistance to the gate lead. Eventually I abandoned that config and I am working with low side only MOSFETs and IGBTs with low RdsON and high dv/dt
Tesla did abrupt switching with spark gap and mercury type low resistance commutators and others confirm that the BEMF effect is most powerful when the time to turn on/off the transistor approaches 0!

kEhYo

[thugugly]

JohnStone,

All I had time to do so far is ;

1. Built low side switch, tested with small incandescent, it lit and flashed.

2. Connected coil with low side switch, worked, and lit cfl, around 300 Hz.

3. Connected incandescent light to Lo and hi side, lit and flashed well. I have a vid ( sorry it's not great quality), which I will load for you as soon as I get home tonight.

I was only switching 24 v.

4. Hooked up coil, and puff, I lost my dc/dc converter, on the high side, at least it got very hot, I shut it down and had to leave, so I'm not sure what has happened yet.

John, I know I suck at vids, so please, tell me what you need me to do if its no good, where you would like scope shots, etc.

Thug