Looking through my attachments I see there is one paper that I have not put on this forum. (If I have already posted it then put this down to memory loss :-[ ). It concerns reports of OU heating from eddy currents induced into a rotating disc. My theory says that the phase shifted eddy current peaks occur when the disc has moved from the maximum induction position between the magnets to one almost over the magnets and that places a circular E field (of value needed to drive the current through the disc resistivity) both within the disc material and just outside its surface. That E field is of polarity to load the electron spins within the magnet thus extracting energy. Effectively each magnet sees a DC circular E field. The combination of electrical phase shift and rotor movement creates the rectification effect that produces this DC field.
Smudge
Quote from: Smudge on 2016.07.27, 16:22:12
Looking through my attachments I see there is one paper that I have not put on this forum. (If I have already posted it then put this down to memory loss :-[ ). It concerns reports of OU heating from eddy currents induced into a rotating disc. My theory says that the phase shifted eddy current peaks occur when the disc has moved from the maximum induction position between the magnets to one almost over the magnets and that places a circular E field (of value needed to drive the current through the disc resistivity) both within the disc material and just outside its surface. That E field is of polarity to load the electron spins within the magnet thus extracting energy. Effectively each magnet sees a DC circular E field. The combination of electrical phase shift and rotor movement creates the rectification effect that produces this DC field.
Smudge
Smudge
Reading the paper,i am wondering if we can do this on a smaller scale,as i am limited with the size of copper i have lying around.
Here is what im thinking-
I have some 5mm thick x 10mm wide copper buss bar.
What if i was to form a loop using this buss bar,and for the rotor i use the rotor from a medium size stepper motor. Reason being,the rotor from stepper motors have many alternating field magnets around them,and they are fairly strong neo's at that. This would then be an achievable frequency range,driven from a DC motor,due to the large amount of alternating magnetic field of the stepper motor rotor.
I have some good powerful 12 volt DC motors,and also a wide range of gears i could use to gear up the rotor.
20 000 RPM on the rotor would be quite doable.
Looking at your paper,at some point during the increasing of RPM of the rotor,i should start to see the load on the prime mover decrease,until such a point where the rotor places no load on the motor,but we still have eddy current heating -->? :-\
ADDED--In saying this,i did notice something a few years back,when using a stepper motor as a generator.
When the stepper motor is driven at higher RPMs with a prime mover,no matter what load you placed on that generator(the stepper motor),no load would be seen at the prime mover :o--i had totally forgotten about these experiment's,as i was carrying them out just a week before we had to shift house,and it only just clicked again when thinking about the above experiment-using the stepper motor in the setup.
5KHz is quite easy to achieve from the output of a stepper motor when being driven by a prime mover.
Brad
To me, the use of your stepper motor rotor seems like a very good idea, but since your question was directed to Smudge, I'll defer to him.
Instead of bus bar, you might also cut a section of copper pipe that would just fit over the rotor, and if you have pipe expansion tools create a very close tolerance fit.
It seems there are many ways to build other versions of this device, some decisions of either axial or radial radial design and the trading of diameter for speed.
Yes, this paper was posted earlier, but it was nice to read it again. I especially like Smudge's model of the dynamo replenishing spin force to the rotating electron charge. Would that we could really tap that!
Quote from: ION on 2016.07.29, 14:50:34
To me, the use of your stepper motor rotor seems like a very good idea, but since your question was directed to Smudge, I'll defer to him.
Instead of bus bar, you might also cut a section of copper pipe that would just fit over the rotor, and if you have pipe expansion tools create a very close tolerance fit.
It seems there are many ways to build other versions of this device, some decisions of either axial or radial radial design and the trading of diameter for speed.
Yes, this paper was posted earlier, but it was nice to read it again. I especially like Smudge's model of the dynamo replenishing spin force to the rotating electron charge. Would that we could really tap that!
Yes,i would have some copper pipe of the right diameter here-some where.
The only reason i was thinking of using the buss bar,is because it is thicker,and would be easy to work with,in way of mounting,and machining to a close tolerance.
This would only take a couple of hours to knock up,and as it is going to be raining cats and dogs here tomorrow,it looks like im work shop bound ;).
So i'll throw it together,and see what we end up with. I will also revisit the high speed spinning of a stepper motor as a generator,and see if i can get that !no load! effect again.
Brad
Brad, you said:
QuoteI will also revisit the high speed spinning of a stepper motor as a generator,and see if i can get that !no load! effect again.
Could you elaborate on this and how you ran the test? I have played with using stepper motors as generators in the past, but am interested in this "no load effect" you refer to.
Thanks in advance.
Quote from: ION on 2016.07.29, 17:12:14
Brad, you said:
Could you elaborate on this and how you ran the test? I have played with using stepper motors as generators in the past, but am interested in this "no load effect" you refer to.
Thanks in advance.
It was some time ago ION,but from what i remember,i had the stepper motor directly coupled to a larger size brushless motor(the hobby type motor from an RC car). At a certain RPM (higher end of what the motor could run at),with a load attached(i believe it was a small incandescent bulb)to one of the stepper motor outputs,the power draw to the motor would go down,and i could hear the load on the motor lift,but the bulb remained brightly lit. Disconnecting the load made no difference what so ever to the amount of power drawn by the motor or RPM. Lower than this RPM value,when connecting the load,you could both hear the motor load up,and see the power draw go up.
I dont have any of the RC gear now,but i have the parts lying around to knock up a quick PWM,and i have quite a few brushed DC motors here as well.
So i'll just finish my coffee,and get right to it,as i had always intended to re-visit this,but just forgot all about it till now.
Brad
OK,here is the first video on the effect i was talking about.
At a certain RPM,i can draw around 2 watts of power from the stepper motor/generator,without it affecting the input to the prime mover-or reflecting on the prime mover.
At the end of the video,i ran the setup without the armature on the stepper motor,to see the difference in power draw from the prime mover.
More to come soon.
https://www.youtube.com/watch?v=8MaJ-Bmoe4Y
Brad
Bellow is a picture of the eddy current DUT.
The copper ring is electrically looped. It is 40mm ID x 10mm wide x 3mm thick-->so OD is 46mm.
There are 4 x 12mm dia x 6mm thick neo N52s in the rotor,with an alternating field pattern-->N,S,N,S
This setup allows me to slide the copper ring over the rotor at different RPMs.
Even at 3200RPM,i still get a large reflection on the prime mover,in that the P/in to the prime mover rises about 900mA to 1 amp when i slide the copper ring over the rotor--the voltage remains as set at the PSU (31v max).
The copper ring gets very hot very fast at the full 3200RPM.
So it may be that my RPM is still to low for this size copper ring ?,as i have no idea as to how Smudge worked out the math in a previous post ???.
So success with the stepper motor/generator setup,but no success with the eddy current heating as of yet.
Brad
Away from home with poor internet connection. Will reply later when I get a WIFI connection.
Smudge
Got WIFI in the village hall so good connection now. Brad, if the input power goes up by 30 watts, does that amount of power explain the fast heating of the copper ring? It really needs some calorimetry. Is there any possibility of fabricating a ring using copper tubing, then you can pass water through the tube, measure its flow rate and temperature rise to get a handle on the power output?
Smudge
Quote from: TinMan on 2016.07.29, 23:11:12
It was some time ago ION,but from what i remember,i had the stepper motor directly coupled to a larger size brushless motor(the hobby type motor from an RC car). At a certain RPM (higher end of what the motor could run at),with a load attached(i believe it was a small incandescent bulb)to one of the stepper motor outputs,the power draw to the motor would go down,and i could hear the load on the motor lift,but the bulb remained brightly lit. Disconnecting the load made no difference what so ever to the amount of power drawn by the motor or RPM. Lower than this RPM value,when connecting the load,you could both hear the motor load up,and see the power draw go up.
I dont have any of the RC gear now,but i have the parts lying around to knock up a quick PWM,and i have quite a few brushed DC motors here as well.
So i'll just finish my coffee,and get right to it,as i had always intended to re-visit this,but just forgot all about it till now.
Brad
Thanks for rechecking this as your time permits. I may also give it a try, but I suggest a resistive load as a lamp can be very non-linear and present odd loading effects to the test.
I may give it a try if I can find a suitable stepper motor.
Edit: Just reviewed your video and it is indeed interesting, and while not OU does raise some questions regarding what is occurring . I suspect that power is being shifted from heating the stepper to the loads when they are connected, although it may be some other magnetic drag that is reduced when the loads are connected. Well done. I will watch it again and take some notes for Pin and Pout at the various settings.
Disregard what I said about the lamps non linear behavior as it does not seem to be a problem in these tests. Might be interesting to try the tests with a heavier load. Is there a sweet spot of loading current that provides a minimum amount of input current draw for each power input level?
Good work!
Quote from: Smudge on 2016.07.30, 15:03:06
Got WIFI in the village hall so good connection now. Brad, if the input power goes up by 30 watts, does that amount of power explain the fast heating of the copper ring? It really needs some calorimetry. Is there any possibility of fabricating a ring using copper tubing, then you can pass water through the tube, measure its flow rate and temperature rise to get a handle on the power output?
Smudge
Just put the whole assembly in a styrofoam (or even cardboard) box and measure temperature rise over ambient of the entire DUT at the inside top of the box. Then compare this to just a resistor in the box with the same wattage input.
This method also takes into account all motor losses.
Quick and simple fixed loss to ambient method, no messy water or plumbing. I've used it many times and it works. If there is OU in the system, you can determine how much by simply running one more test where you bring the resistor to the same heat level, and note the increase (difference) in power required to do so. This is then your gain.
I've used and recommended this method many times, and although not perfect it will get you close enough.
Edit: regarding your test, there may not be enough poles on the rotor to get the effect Smudge is looking for.
You can get lots of poles with just one magnet by fabricating 2 pieces of soft iron with articulations in the edges that sandwich a magnet, such as in an automotive alternator's rotor. Creative design of the rotor assembly can lead to some interesting shaped fields induced into the copper.
Quote from: Smudge on 2016.07.30, 15:03:06
Got WIFI in the village hall so good connection now. Brad, if the input power goes up by 30 watts, does that amount of power explain the fast heating of the copper ring? It really needs some calorimetry. Is there any possibility of fabricating a ring using copper tubing, then you can pass water through the tube, measure its flow rate and temperature rise to get a handle on the power output?
Smudge
Smudge
Can the copper ring made from tube be open each end?,as eddy currents would still be induced into the copper tube with the ends open-much like dropping a magnet down a copper tube.
I could do as ION said,and house it all in an insulated box,and measure temperature rise over time against a resistor with the same power flowing through it.
@ ION
Would i have a small circulation fan in the box to circulate the air around in the box--like a small PCU fan ?.
Brad
Quote from: ION on 2016.07.30, 15:07:50
Thanks for rechecking this as your time permits. I may also give it a try, but I suggest a resistive load as a lamp can be very non-linear and present odd loading effects to the test.
I may give it a try if I can find a suitable stepper motor.
Good work!
QuoteEdit: Just reviewed your video and it is indeed interesting, and while not OU does raise some questions regarding what is occurring . I suspect that power is being shifted from heating the stepper to the loads when they are connected, although it may be some other magnetic drag that is reduced when the loads are connected. Well done. I will watch it again and take some notes for Pin and Pout at the various settings.
I can easily check the temperature theory.
I will place a temperature probe on the stepper motor housing,and let it run for 10 minutes unloaded.
I will then place the two loads on the stepper motor output's,and if the power is being shifted from heating to the loads,we should see a temperature drop at the stepper motor housing--correct?.
QuoteDisregard what I said about the lamps non linear behavior as it does not seem to be a problem in these tests. Might be interesting to try the tests with a heavier load. Is there a sweet spot of loading current that provides a minimum amount of input current draw for each power input level?
There is something odd going on with this setup,so see if you can make any sense of it.
No matter what load i put on the outputs of the stepper motor,the current value always remains at around 69mA per leg,and only the voltage value changes.
E.G,if i place those small incandescent bulbs across the outputs of the stepper motor,the current will be 69mA through each bulb ,at around 14.7V RMS. If i place larger incandescent bulbs across each leg,the current remains at 69mA,but the voltage across each bulb will drop.
The weather is bad again here today,so looks like another day in the workshop O0 ,so i will keep at the stepper motor testing a little longer,and sort that out first,and then move onto the eddy current heating,as i believe the two are related,in that you can create a delay of the lorentz force<--would this be the correct term to use here?
Anyway,so first test is the temperature test, without load,and then with load.
Second will be using a VR,so as we can increase or decrease resistance on the fly,and watch the current as we do so.
Oh,and one last thing.
I placed a 240v AC LED bulb on one of the outputs of the stepper generator,and it lights up nice and bright--BUT the odd thing is the voltage and current are very close to being 90* out of phase from the generator output,but still places a load on the prime mover when connected--i have not had a look at the phase relationship using the incandescent bulbs yet,but will do so today.
Brad
It would seem that we are indeed converting heat (or some of it) to electrical power.
So at a guess,i would say that we are reducing the amount of eddy currents flowing through the core,when we draw a load from the two generating coils. I will not know exactly how much until i box the whole setup,and switch to a much more stable power supply--E.G,batteries and a big VR.
The one mistake made here is the fact that i did not increase the P/in back up to the same value as it was without the load placed on the coils/generator. All things being equal,i should have raised the P/in back up to the same value,once i switched on the bulbs. But i would also have to switch to the batteries,to obtain a very accurate P/in value,as the mains power around this area is not very stable.
https://www.youtube.com/watch?v=1IVxO94mcB0
Brad
Quote from: TinMan on 2016.07.31, 06:08:17
It would seem that we are indeed converting heat (or some of it) to electrical power.
So at a guess,i would say that we are reducing the amount of eddy currents flowing through the core,when we draw a load from the two generating coils. I will not know exactly how much until i box the whole setup,and switch to a much more stable power supply--E.G,batteries and a big VR.
The one mistake made here is the fact that i did not increase the P/in back up to the same value as it was without the load placed on the coils/generator. All things being equal,i should have raised the P/in back up to the same value,once i switched on the bulbs. But i would also have to switch to the batteries,to obtain a very accurate P/in value,as the mains power around this area is not very stable.
https://www.youtube.com/watch?v=1IVxO94mcB0
Brad
Yes, the very same thing happens with power transformers that are operating in saturation, without a load. When a load is placed on them, the saturation eddy current losses are gone, and the heat that the core experiences is drastically reduced, as the transformer is now operating in it's linear design region.
This tends to fool a lot of folk that don't account for the transformer temperature in their observations.
Nevertheless, in a rotating machine, perhaps it can be exploited as Smudge teaches.
One note on the use of thermocouples: for very accurate readings best when up to 1-1/2 to 2 inches can be inserted into a hole bored in the motor casing, as the leads themselves tend to pull heat from the measuring junction (tip). Also good to note the ambient changes during tests such that they can also be factored in.
Good work, Brad
OK, i think i may have the setup needed for the inductive heating test.
I went through a few boxes of parts i have lying around,and fount a 400 watt 180VDC motor,and a rotor from an old 3 phase washing machine motor,that has 10 alternating magnetic poles around it.
The motor will do 4000RPM,and so that gives us a frequency of around 660Hz--will this be high enough to get the effect we are looking for?.
So now all i need is a 180VDC power supply C.C
Here is what im thinking-quick and nasty i know,but will it be ok for the job?-->see schematic below.
Brad
Brad
I hope that is a large power rheostat for adjusting the current, otherwise you will let the smoke out.
Do you have a Variac you can throw on the front of the bridge rectifier? If not a light dimmer up front might work as long as you have the dummy light bulb load in also.
The rotor and motor look nice.
Quote from: ION on 2016.08.01, 01:25:56
Brad
I hope that is a large power rheostat for adjusting the current, otherwise you will let the smoke out.
Do you have a Variac you can throw on the front of the bridge rectifier? If not a light dimmer up front might work as long as you have the dummy light bulb load in also.
The rotor and motor look nice.
Yes,i have a large 500 watt wire wound rheostat-see pic below
The lightbulb was to keep the voltage at an RMS value,and not charge the cap to the P to P value.
I dont own a variac,but it is on my wish list.
Brad
Just got temporary internet connection again. I like Ion's styrofoam box idea and would recommend that rather than fiddling about with copper tubes and water pumps.
Smudge
Brad said:
QuoteThere is something odd going on with this setup,so see if you can make any sense of it.
No matter what load i put on the outputs of the stepper motor,the current value always remains at around 69mA per leg,and only the voltage value changes.
E.G,if i place those small incandescent bulbs across the outputs of the stepper motor,the current will be 69mA through each bulb ,at around 14.7V RMS. If i place larger incandescent bulbs across each leg,the current remains at 69mA,but the voltage across each bulb will drop.
So the stepper motor output is acting like a near pure current source. The only way I can think this can happen is if due to the nature of the construction of the stepper motor, i.e. it reaches a limit in magnetic energy transferred per pole of rotation due to a shunting effect.
It may be useful to investigate this more fully. Perhaps Smudge has a much better explanation.
Quote from: ION on 2016.07.29, 14:50:34
To me, the use of your stepper motor rotor seems like a very good idea
Is this motor what you are talking about ?
Stepper motorhttps://en.wikipedia.org/wiki/Stepper_motor
A stepper motor or step motor or stepping motor is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor's position can then be commanded to move and hold at one of these steps without any feedback sensor (an open-loop controller), as long as the motor is carefully sized to the application in respect to torque and speed.
Switched reluctance motors are very large stepping motors with a reduced pole count, and generally are closed-loop commutated.
Quote from: evolvingape on 2016.08.02, 16:22:51
Is this motor what you are talking about ?
Stepper motor
https://en.wikipedia.org/wiki/Stepper_motor
A stepper motor or step motor or stepping motor is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor's position can then be commanded to move and hold at one of these steps without any feedback sensor (an open-loop controller), as long as the motor is carefully sized to the application in respect to torque and speed.
Switched reluctance motors are very large stepping motors with a reduced pole count, and generally are closed-loop commutated.
Yes ,that is a basic drawing, there are many variations on that theme.
Quote from: ION on 2016.08.02, 15:51:55
Brad said:
So the stepper motor output is acting like a near pure current source. The only way I can think this can happen is if due to the nature of the construction of the stepper motor, i.e. it reaches a limit in magnetic energy transferred per pole of rotation due to a shunting effect.
It may be useful to investigate this more fully. Perhaps Smudge has a much better explanation.
It dose seem to act in an odd way.
But first a question-->and this may sound silly,but C.C
When measuring AC current and voltage,how do we know which way-or,from what device(source) the bulk of the power is coming from?.
To make my question more clear,lets say we have two black boxes,and we have a common or neutral wire from one box to another,and a live (or hot) wire with a 1 ohm CVR in series on the hot wire to measure the current flowing from one to the other black box. Lets assume that it's an AC current flow. So we place one channel of our scope across the neutral/common and live wires to measure voltage. We then place the second channel of the scope across the CVR to measure current. Without knowing which black box is the power source,and which is the sink,how do we know which way the power is flowing ?.
There is a reason for this question.
Below is a schematic of two circuits-along with scope shots.
The first circuit you will see a VR (which is 200 ohm's-forgot to put that value in the schematic),a 1 ohm CVR,and the stepper motor,which is being used as our generator.
The first 4 scope shots show the various resistance settings on the VR(which is our load on the generator), and the associated voltage and current traces in the scope shot for the stated resistance value of the load.
You will see that the maximum current the stepper motor can produce is 76mA.
The last scope shot shows the values taken when the second circuit is use,and that is just replacing the resistive load with the 240v mains LED bulb. I have no idea as to what the circuit inside is,as i cannot get it apart without breaking it--it is not as simple as the CFLs to get apart.
So if the maximum current that the stepper motor can produce is 76mA,then how is it that it can now produce over 270mA of current when the LED bulb is used as the load. We also now have 256 volts across the LED,but as you can see,the phase relationship between voltage and current is near 90* out close to 80* i would say.
But my question is--when using the LED as the load,how do we know that the bulk of the power is flowing from the stepper motor to the LED,and not from the LED to the stepper motor,as the stepper motor just will not produce this kind of current-regardless of RPM. Even with a dead short across the stepper motor outputs,there is no reflection seen on the prime mover(as seen in other video's)and no increase of current above that 76mA.
The other thing is,there is suppose to be over 250 volts AC across that LED,and it dose light very bright-->but i can hold the bare wires in my hands while the LED is shining brightly,and i get hardly any sort of a tingle at all :o
What kind of electricity is this :D
Brad
Dear Brad.
I have 7 W LED lamps in use all over the house. Our house is ancient, 316 years old! No ceiling roses, wall lights. I had to open one to direct the light more downward.
They are SMD LED's with a bridge and a storage cap, plus a few dropping resistors.
I can provide a photo if you want one.
Cheers Grum.
Quote from: Grumage on 2016.08.03, 13:20:08
Dear Brad.
I have 7 W LED lamps in use all over the house. Our house is ancient, 316 years old! No ceiling roses, wall lights. I had to open one to direct the light more downward.
They are SMD LED's with a bridge and a storage cap, plus a few dropping resistors.
I can provide a photo if you want one.
Cheers Grum.
That would be great Grum.
So just a FWBR,cap and resistors to drop the current?
So how then is this pumping up the current like some sort of tank circuit,as i assume that the cap is after the FWBR,to smooth out the pulses the LEDs would see.
Brad
Food for thought.
The nature of a reactive circuit such as a tank circuit is that you can produce thousands of volts and thousands of amperes with just a tiny excitation, depending on the "Q" of the circuit. Theoretically, in an ideal L-C circuit the voltage and current would go to infinity, but in the real world this is not possible, as the dielectrics would break over long before that.
It does take many input impulses for the energy to accumulate in the reactive circuit, but once it does build to it's maximum value, it will stay at that high value, limited only by the resistive and radiative losses of the tank circuit. These tend to bleed off real power which must be resupplied by the source of excitation.
Thus far all "known" attempts to get at that reactive power and have it do real work by becoming real power, have AFAIK failed, but it is an area ripe for investigation.
I have postulated that the key to OU may be in using high Q circuits to advantage by not directly bleeding off the circulating energy, thus lowering the Q, but letting it build such that it can act as a catalyst in a reaction which releases energy from "some other potential source". A catalyst is typically "not used up" in the reaction, but acts as a trigger.
If you could capture the instant of connection of your LED lamp to the stepper output with your scope you would probably catch the first impulses from the stepper motor pumping up the tank circuit. It would look like an oscillation that builds in amplitude with each cycle.
So for each cycle a max of 76 mA is pushed into the tank until it accumulates it's maximum, which is limited by the stepper winding resistance and the power dissipated in the LED.
If you try tuning the output of the stepper motor with a capacitor of the right value, instead of the LED lamp, you should get even higher values of voltage and current circulating in the tank.
You asked:
QuoteBut first a question-->and this may sound silly,but C.C
When measuring AC current and voltage,how do we know which way-or,from what device(source) the bulk of the power is coming from?.
To make my question more clear,lets say we have two black boxes,and we have a common or neutral wire from one box to another,and a live (or hot) wire with a 1 ohm CVR in series on the hot wire to measure the current flowing from one to the other black box. Lets assume that it's an AC current flow. So we place one channel of our scope across the neutral/common and live wires to measure voltage. We then place the second channel of the scope across the CVR to measure current. Without knowing which black box is the power source,and which is the sink,how do we know which way the power is flowing ?.
One way to do this is by measuring the voltage across the CVR with respect to ground, this should tell you which direction it is flowing. If it is flowing out of the source into the DUT, it will be higher on the left and lower on the right side of the CVR, and vice versa.
Also if you compare the phase of the current across the CVR WRT to the voltage input you can tell which way it is flowing if it is a pure resistve load. If it is reactive, it gets trickier.
Quote from: TinMan on 2016.08.03, 13:31:30
That would be great Grum.
So just a FWBR,cap and resistors to drop the current?
So how then is this pumping up the current like some sort of tank circuit,as i assume that the cap is after the FWBR,to smooth out the pulses the LEDs would see.
Brad
Typically the cap responsible for resonance in your stepper setup is in series with the bridge and the mains (220nF), acting as a dissipation-less resistor dropper at, in your case, 50Hz. (as shown in the attachment). The other cap (4.7uF) is the smoothing cap.
You can calculate the effective resistance or impedance at 50 Hz if you know the value of the cap. It is this cap that is resonant with the stepper motor winding (inductance). The rest of the components in the lamp are lossy items that lower the Q of the resonant circuit.
That's why I suggested just using a cap tuned for peak resonance on the output of your stepper motor.
If you draw out the equivalent circuit you will see it.
These are the dimmable LED lamps, other types with a switching circuit are supposedly not dimmable.
Quote from: TinMan on 2016.08.03, 13:31:30
That would be great Grum.
So just a FWBR,cap and resistors to drop the current?
So how then is this pumping up the current like some sort of tank circuit,as i assume that the cap is after the FWBR,to smooth out the pulses the LEDs would see.
Brad
No problem......
O0
Quote from: Grumage on 2016.08.03, 13:47:27
No problem......
O0
Ah--different type of bulb.
Mine may be different inside ?.
Brad
Here is the one i have,pictured below.
As you can see,i have already tried to break into it lol,without success :-[
Hi Brad.
You might be correct however the front end of my lamp has a low value ( capacitance Unknown ) high voltage cap in series with an SMD resistor directly across the incoming 240 V input. Tank circuit? ;)
Cheers Grum.
Quote from: ION on 2016.08.03, 13:45:56
Typically the cap responsible for resonance in your stepper setup is in series with the bridge and the mains (220nF), acting as a dissipation-less resistor dropper at, in your case, 50Hz. (as shown in the attachment). The other cap (4.7uF) is the smoothing cap.
You can calculate the effective resistance or impedance at 50 Hz if you know the value of the cap. It is this cap that is resonant with the stepper motor winding (inductance). The rest of the components in the lamp are lossy items that lower the Q of the resonant circuit.
That's why I suggested just using a cap tuned for peak resonance on the output of your stepper motor.
If you draw out the equivalent circuit you will see it.
These are the dimmable LED lamps, other types with a switching circuit are supposedly not dimmable.
Thanks ION
I will get my box of caps out,and see if i can find one that will get the resonant tank going,as with the LED bulb.
I did try a couple of microwave oven cap's,but it would seem they were far to large a value.
It would be good if we could design a variable cap with a value range of say between 50nF and 1uF :)
Brad
@ ION
Did you read my post 23?
What i would like to know how to do,is be able to shift the voltage/current phase angle.
I want to try and get the current and voltage out by exactly 90*,and see what happens.
This is in relationship with that question posed by Poynt--can you produce real power when the current and voltage are out by 90*. Is there some way of being able to shift the phase angle on the fly ?-some sort of !inline! circuit i could make up ?.
Thanks
Brad
Dear Brad.
A large ranged variable capacitor would be a wonderful asset in our game!
As I see it the only way would be to use variable inductance. In the late 70's a lot of car radios used variable inductance tuning with a slug of ferite that moved in a solenoid coil. Perhaps you could engineer something on that line.
Cheers Grum.
Quote from: TinMan on 2016.08.03, 14:37:46
@ ION
Did you read my post 23?
What i would like to know how to do,is be able to shift the voltage/current phase angle.
I want to try and get the current and voltage out by exactly 90*,and see what happens.
This is in relationship with that question posed by Poynt--can you produce real power when the current and voltage are out by 90*. Is there some way of being able to shift the phase angle on the fly ?-some sort of !inline! circuit i could make up ?.
Thanks
Brad
Any high quality inductor
or capacitor in series with an AC source will shift the current away from voltage by 90 deg.
A capacitor will cause the current to lead the voltage and for an inductor the current will lag the voltage.
If you require more than 90 deg, it can be done with additional components.