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Author Topic: Has anyone seen Lasersabers new motor runs on 1000uf cap  (Read 293476 times)

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #45 on: May 29, 2013, 07:05:02 AM »
Looking it over again, he blew with the straw and said it really makes the voltage go up fast. Well I would think so. lol  But it also speeds up faster. But after the speedup, he drags it down and then it accelerates, probably due to the cap being charged.

But still, what is that a 10uf cap at 100v. This is just insane!!!  lol
The germanium diode. I suppose it conducts both ways, if the cap is discharging and recharging and it is in series with the cap.

He posted specs at his forum.

Mags

conradelektro

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #46 on: May 29, 2013, 02:00:50 PM »
Gyula, thank you for your comments.

Today I tried with the ALD110900, and it was a failure.

Attached is the circuit and a scope shot with the ALD110900. The rotor stopped turning, even with 7 Volt power supply. The power draw was very little, about 70 µA.

(The circuit diagram does not show it, there was a diode over the drive coil to clip off the back EMF spikes, as one can see in the scope shot.)

The trigger coil idea seems to be not very good, I will use a Reed switch like Lasersaber. But it will have to wait till next week.

Greetings, Conrad

P.S. http://www.overunity.com/13523/has-anyone-seen-lasersabers-new-motor-runs-on-1000uf-cap/msg361696/#msg361696 this was my test with the 2SK170

gyulasun

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #47 on: May 29, 2013, 03:00:48 PM »
Hi Conrad,

If you feel like to return to the 2SK170 again till the reed switch arrive I edited your schematic to include a potmeter, a resistor and a 1.5V small AA or AAA or a button cell battery to insure a negative bias to the gate of the JFET so that it should be just OFF at its pinch-off gate voltage or slightly beyond it.  And the induced trigger AC voltage will control the gate whenever the algebraic sum of the DC and AC voltages fall into the conducting range of the JFET.  (it is possible you may have to use a 3V battery or two 1.2V batteries in series.)  This negative bias does nothing else but helps the JFET return to its OFF state from its ON state whenever it is needed but the induced AC trigger voltage changes slowly in amplitude (not rectangular but sinusoid-like).
This way you may be able to improve the run time of your setup considerably.

I guessed the ALD110900 test would be worse than the JFET test (it has a much higher ON resistance than the JFET).
Thanks for showing the results.

Greetings
Gyula

conradelektro

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #48 on: May 29, 2013, 08:28:53 PM »
Gyula, thank you for editing the circuit, I will try that.

I could quickly test the motor with a Reed switch. See the circuit diagram and the photo. Still, much more power draw than Lasersaber reported with his first 3D-Printed Motor (the one with the six coils).

May be Lasersaber`s coils have a higher DC resistance than 90 Ohm?

The Reed switch seems to be "ON" for too long (almost 50% of the time). I have to make an iron shield (slit) in front of it, to limit the ON-time when a magnet passes. Or I have to place it at a better position in respect to the passing magnets.

I tried a 5 K Ohm resistor in series with the coils. This limited the average current draw to about 90 µA at 1 Volt supply Voltage and the rotor still turned slowly. But it is stupid to burn the energy in a resistor. There should be 5 K DC Ohm worth of coils.

Greetings, Conrad

Farmhand

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #49 on: May 29, 2013, 10:58:54 PM »
Hi Conrad, excellent work and investigations, the speed with which you made a replication is remarkable. Well done, very impressive. We need more folks like you and LidMotor who can whip up a very good replication in quick time to test things out, and say it as they see it. I agree about the resistor. And I also see the DC resistance of the turns as avoidable loss, to restrict the current and keep ampere turns without the DC resistance I think we can use more inductance, shorter "on times" and more voltage if necessary. One of the reasons I don't like to use small coils is that to get enough turns the wire needs to be thin and so the DC resistance is relatively high, which wastes energy as heat.

If we adjust the "on" time while the coil is in use we can adjust the "on" time so that because of the inductance the current restricted, but if the "on" time is too long the coil gets enough time to act as a conductor with just DC resistance. The frequency of the input "on" times is also a factor there.

Two motors side by side one has 20 Ohms DC resistance in it's motor coils and the other has less than 1 Ohm DC resistance in it's motor coils both have the same inductance and are adjusted to an input of 10 Watts from the same potential supply, which one wastes more energy as heat ? Seems obvious.

Cheers

wattsup

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #50 on: May 29, 2013, 11:50:15 PM »
@conradelektro

I have a hunch and am wondering if you can try to put the reed between coils 3 and 4 and remove the power feed and try it cold turkey like @LS is doing?

Since we know that inductors discharge at disconnection and capacitors discharge at connection, what I am thinking is that putting the reed at the end of the series coils as you have it now then in series with the cap is not giving enough inductive recharge to the capacitor since the reed is blocking one side of the capacitor. But putting the reed at coils 3 and 4 will ensure that both inductor sides will discharge into the cap at disconnection.

wattsup


Pirate88179

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #51 on: May 30, 2013, 04:03:31 AM »
Conrad:

Wow!  That is a great looking rotor and coil assembly you have over there.  All built the old fashioned way too.  Very nice work...and fast too.  I wish you the best of luck with your replication.

Bill

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #52 on: May 30, 2013, 04:32:55 AM »
Either I am missing it or we still dont have number of turns for the coils. Maybe since we have the dimensions of the bobbins, we are to just fill them to the rim. Fill one while counting turns then make duplicates. Maybe the difficulty mentioned of these is that the wire is 46awg and the printed bobbins have imperfections that the wire catches on while winding. Not sure.

Well with those figures in mind I suppose an inductor calculator can be used to come up with inductance approximately. Im interested in these numbers and resistance.

Im still bungled by the diode in series with the coil, reed and cap. I would think that once the cap is charged to max potential of generation, that it would stop working.
I really dont want to be a party pooper. But in my mind, especially with the introduction of that diode in a circuit that all parts are in series, the only way I can imagine it to run like it does is that there must be another source. Even without the diode, a source would work, but the diode has me stumbled. Unless the voltages beat the diode into free passes through the back door.  ;D

Then the only other possibility is that all the windings in series, if the total length of wire is very very long, long enough for there to be large potential differences between far ends(delays, phase relationships) then maybe there is some bounce or say lopsided compression from one end of the total length of wire to the other.  Then again, the thing runs at different speeds producing different freq at each rpm level.  Idunno.

Driving me nuts already. :o :o :o ;D

Mags



lumen

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #53 on: May 30, 2013, 05:55:26 AM »
Was that 42 awg?

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #54 on: May 30, 2013, 05:59:42 AM »
oops  yep  42 awg.   Kinda like splittin hairs.  ;D

Mags

lumen

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #55 on: May 30, 2013, 06:53:31 AM »
I thought the diode on the cap was funny also! If it was connected in one direction, it could only serve to charge the cap and nothing could flow out to power the motor.

If it was connected in the other direction, then it could not charge the cap but the energy in the cap could flow out to run the motor.

Something isn't making sense with that diode unless it's just burnt out and conducts in both directions.



conradelektro

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #56 on: May 30, 2013, 07:54:34 AM »
@Farmhand: I was just thinking, how can one adjust the ON-time with Reed switch? To everybody, any ideas? Iron shield (slit)?

@Wattsup: I will try the Reed switch in the middle of the coils as you suggested.

I tried a diode at the capacitor (both directions, both sides of the capacitor). But it did nothing once the battery or power supply was disconnected.
I tried with this schematics http://www.overunity.com/13523/has-anyone-seen-lasersabers-new-motor-runs-on-1000uf-cap/msg361768/#msg361768

Will be back on Monday.

Greetings, Conrad

gyulasun

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #57 on: May 30, 2013, 10:25:17 AM »
Hi Conrad,

The ON time of a reed switch could be influenced:

By tinkering with the distance and angle from the rotating magnets (if rotor magnets are too strong, their flux may influence reeds at distance of 4-6 cm, rendering the positioning very critical

By using two reeds in series, the reeds being at certain distance from each other

By using a separate small rotor disk fixed on the same shaft, with small magnets on it, just for controlling the reed,  this disk is being independent from the main rotor magnets. 

You mention iron shield: it sounds good to me, although it may cause some drag to the rotor magnets, depending on its size and permeability.

Gyula

TinselKoala

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #58 on: May 30, 2013, 04:47:55 PM »
I thought I had already posted the fact that a reed switch can be "tuned" by using a small fixed magnet on the opposite side of the switch from the moving triggering magnets. You can get almost complete control over the duty cycle of a reed switch by carefully choosing and moving this bias magnet until you get the reed performance you need. Also, putting a small ceramic cap directly across the reed as close as possible to the switch will help to preserve your switch contacts and doesn't cost anything (much) energetically.

The cap in Lasersaber's video is marked 10K 100. A poly film cap of that size cannot possibly be 10 microFarads. Looking on the internet for capacitor marking codes, I find that the "K" means thousands of picofarads. So 10K means 10 thousand picofarads, or 10 nanoFarads, or 0.01 microFarads.
http://www.electronic-circuits-diagrams.com/tutorials/capacitors.shtml

The energy stored in a 0.01 uF cap at 100 volts is (0.00000001)x(100)x(100)/2 Joules == not very much, 0.00005 Joules. From previous experience with jewelled pivot bearings and magnet rotors, I'll estimate that the power dissipation of that little rotor at the speeds we are seeing is on the order of only a couple of milliWatts. Maybe even less, hundreds of microWatts perhaps. Or even less.... since the cap seems to be able to accelerate the rotor from slow, and keep it running for tens of seconds.
It would be nice to see some instrumental data. The rotor could be spun up to a known RPM then allowed to run down, unpowered, and carefully timed. The average of a dozen such runs to the same RPM would be a number that could be relied upon. The rotational Moment of Inertia of the rotor can be easily calculated if the weights of the components are known. This value along with the RPM will give the energy stored in rotation, and the average rundown time will then give an average power dissipation value over that RPM range. Then the testing with the cap could commence. Use the air blast to run the rotor to a known RPM again with the cap switched out of the circuit. Then switch in the cap and time the rundown time. The difference in the powered vs unpowered rundowns will allow you to see how efficient the capacitor really is, whether the system is putting any energy back into the cap while it's running down, and will allow you to determine whether or not any further mods help or hurt.

TinselKoala

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #59 on: May 30, 2013, 06:01:36 PM »
@Mags:
Disconnect the capacitor and diode from the coils, and spin the rotor while monitoring the coil output on the scope. The rotor magnets passing the coils makes AC, right?

How are you going to charge up a capacitor with AC, unless you also have a rectifier in series with the cap?

Further.... if the diode conducts in both directions.... it's not a diode. A 1n60 germanium would probably handle the strain OK and act as a rectifier with low forward voltage. A Schottky diode might work even better.