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Author Topic: Has anyone seen Lasersabers new motor runs on 1000uf cap  (Read 294590 times)

gyulasun

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #240 on: June 30, 2013, 11:29:50 AM »
Hi Conrad,

Re 1) 
I would be curious to know whether you have an explanation on the increase on power draw and on the simultaneous rpm decrease when the feedback diode is used (at the some ten mW input power levels or less) to utilize the energy of the collapsing field.  I also thought of a possible 'masking' effect of the low impedance coils at higher power levels to notice any increase in power draw but my common sense tended to rule out this possibility because the presence of the diode and its associated circuit components must be 'invisible' power-draw-wise to the input supply source.  I also thought that with high impedance coils, especially when they are in series to have an even higher impedance (both AC and DC wise), any circuit component placed in parallel with them may reduce their high impedance and "predestinate" the drag but again my common sense says that the switch is OFF (i.e. input power is cut to the coils) when the collapsing field is utilized so no increase in input power draw ought to be sensed. The decrease in rpm may involve a different explanation: the just interrupted current in the coil(s) is maintained by the diode (and by its associated components) till the collapsing field fully diminishes and this makes sense to me to be able to influence the original rpm of the rotor.   

Re 2)
How the DadHav circuit works (you wonder why it works at all)?  Well, let's consider first the pnp - npn bipolar transistor circuit with MPS-A56, -A06 types). These both types have a minimum DC current gain (hFE) of 100 and not higher than 150 (from data sheet). This means their current gain is relatively well defined so it is easier to replicate most circuits with these types.

Basically the DadHav circuit is a DC coupled switching circuit but it can only operate with AC pulses injected either via the coils by induction or by injecting pulses into the base of the pnp transistor (via say a coupling capacitor).
Notice that without any AC input, there can be no DC current flowing via the transistors when you apply supply voltage because none of the transistors can receive any DC forward bias at its base (putting this otherwise: both transistors are in Class C mode of operation without any DC bias).

The moment an AC pulse is induced in the coil(s) with a polarity that is able to bias the pnp transistor into conduction via the 100 kOhm,  the npn transistor will also conduct because a bias current is injected into its base from the supply voltage via the pnp transistor and the other 100 kOhm, hence the coils can operate as electromagnets. When the inducing magnet passes the coil(s), the circuit should finish operation (if it has correct component values of course, see below) because in the lack of any AC input pulse, the lack of any DC bias prevails again.

Obviously there can be "issues" with the operation as follows: if the induction somehow can induce a prolonged AC bias into the pnp base (say the magnets are too strong or too close to the coils etc) then the electromagnets' ON time may become spuriously controlled, this is what I think you solved with using the 2.2 nF capacitor, effectively reducing the induced AC amplitude by forming a (lowpass) integrating filter with the series 100 kOhm base resistor.
The next "issue" with this circuit is the DC resistance of the coils if the resistances are relatively high: if the npn transistor is able to drive a certain current via the coils which current causes a high enough DC voltage drop across the coils, then this voltage drop may be able to insure a continuous DC bias to the pnp transistor via the 100 kOhm, meaning the pnp cannot switch off: so both transistors remain in ON state, regardless of any further magnet inductions.  To put this process simpler: the moment the npn transistor saturates it biases the pnp transistor via the 100 kOhm and this state remains because the pnp will keep the npn in ON state too: a locked situation. Consider this in you MOSFET circuit version, the same problem may occur when the MOSFET is fully ON.   

I believe that these "issues" could be remedied by using a variable resistor across the base-emitter of the pnp transistor, say a 100 kOhm potmeter first and see its effect when adjusting its value. I believe even the 2.2 nF could be removed and still get a correct ON pulse. A second 100 kOhm potmeter placed between the base and emitter of the npn transistor may also help for fine adjusting or when the first 100 kOhm potmeter at the pnp may need a too low kOhm setting and this would attenuate also the AC trigger pulse to the base of the pnp.

Now you can understand that in case the transistors have a high DC current gain, the chance for collector-emitter saturation is higher: thus the operation of the circuit may become also problematic as you found with the BC547-549 types, these may have a hFE of 300 to 700 so the 100 kOhm resistors may have to be increased to some hundred kOhm or even to 1 - 4.7 MegaOhm values to get a better chance for correct operation.

These latter transistor types (you also refer to in your above post) recall your test with the Ossi motor 1 reed 2 transistor circuit:
http://www.overunity.com/13523/has-anyone-seen-lasersabers-new-motor-runs-on-1000uf-cap/msg363434/#msg363434  and I mention this because both transistor types are npn and none of them is pnp. If you simply mistyped the names in the schematic or in your above post that is okay but if you really used two npn types then it may explain why the circuit was willing to operate from 12V supply voltage and at higher voltages only: one of the npn transistors got a reverse bias and behaved as a 12V Zener to block any input current below 12V?  (base-emitter junctions behave as Zener diodes in reverse biased condition) Sorry for mentioning this, I do not assume you used two npn types but only mistyped the names. (originally BC238-BC558 npn-pnp types were used in the video.)

Sorry for this long post,  I hope it serves you and others fully understand the operation of DadHav's circuit.

Greetings, Gyula

PS  Re  SeaMonkey's suggestions I can agree with his 1st suggestion to reconnect the 100 kOhm resistor from the drain of the MOSFET to the emitter of the pnp i.e. if I understand well: connect the 100 kOhm between the base and the emitter of the pnp and use a suitable capacitor to couple the AC induction from the drain of the MOSFET to the pnp base, this way the DC coupling is eliminated to the base of the pnp from the drain, preventing the possibility of the locks up situation. Regarding his other suggestions the result is doubtful because you (Conrad) described your findings with tinkering with those resistors and found the best values empirically for this particular circuit. (unless you make the change mentioned in the 1st point by SeaMonkey.)

conradelektro

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #241 on: July 01, 2013, 02:32:58 PM »
@SeaMonkey: Thank you for the suggestions I will try them.

@Gyula: Thank you for the explanations, that helps a lot.

You are right  I made a very stupid error, I thought the BC549 is a PNP transistor. What would be a good complementary pnp type for the BC547 or the BC 549?

It is very akward to use my cell phone for the Internet, will be back next week.

Greetings, Conrad

gyulasun

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #242 on: July 01, 2013, 10:24:09 PM »
Hi Conrad,

To err is human.  At least one puzzle is solved (the needed higher than 12V supply voltage).
The complementary pnp types for the npn BC547-549 are the BC557-559, data sheet is here:
http://www.play.com.br/datasheet/BC557.pdf   

Good pnp types are also the BC327 or BC328,  these are also selected by hFE but are not labeled with letters A, B or C but with numbers in the suffix:   -16    -25   or   -40  like  BC327-25  and see data sheet how these groups include the hFE ranges:
http://www.play.com.br/datasheet/BC327.pdf    These pnp types have their complement npn types as BC337, BC338 with the same number suffix classifications in hFE.

rgds,  Gyula

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #243 on: July 03, 2013, 06:37:30 AM »
Had to clear the bench and some of my apartment because of tenting for termites at the other end of the building, so im just getting things all back to normal. What a pain in the butt it all was.

At work a parts and hardware guy comes by once a week. While looking for supplies in his truck, these clips for car door panels caught my eye. Pic below. The other pic is of my wire stand for coil winding and my rotor Im going to use. Its not a needle bearing but these bearings and base are the ones I used graphite in the bearings after cleaning out all the grease. Over 14min rundown from 1200 rpms. Its on YT. 2 vids because they only gave us 10 min back then. ;D

The winding length is short and the outer diameter for winding is the size of a penny. There will be 24 coils for this build. Will be winding the coils using the laser rpm meter in count mode to count the turns of the drill to count the turns. The wire is so fine. I saw a pic of its cross section compared to the cross section of an average hair. The wire is smaller. Not quite half. Building the stator base ring tomorrow.

Working on a rotor and base for the tiny bobbins I had shown earlier, and going ahead with this build first.

Mags

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #244 on: July 03, 2013, 07:21:06 AM »
Almost forgot.  These will be wound bifi. Imagine each coil has 2 wires wound bifi and 1 wire is labeled at the ends 'A' and the other wire is labeled 'B'. 
All 24  'A' wires will be wired successively in series and all the 'B' wires are wired in series, then the 'A' series circuit will be connected in series with the 'B' series circuit.

There is a reason to wire them this way that I think has a pretty cool outcome.

If I wire each bobbins bifi windings in series, where we only have 2 wires for connection with the bobbins coil, and then just connect it in series with the next series bifi coil, and then the next, we will be dividing the input voltage amongst the coils/bobbins as a whole. So we have 24 bifi coils in series and we end up with 2 wires for input(or output  ;D ). Lets make it simple.  We will provide 24v to the motor. Well we have only 1v across each series bifi on each bobbin. :o   Not good. Thats only .5v between adjacent windings! :o :o

But, if we do as I suggest above, by putting all the 'A' wires in series and all the 'B' wires in series, then series 'A' and 'B' we will then have 12v between all adjacent windings throughout, not just .5v .   This is a 24 times increase in voltage in the capacitance of adjacent windings. Not a bad gain in the potential of the coils capacitive effects. Just by a trick move in connecting the ends of each bifi.  ;)   Think about it.

If some people out there have used series bifi in series with other series bifi coils, they may not have gotten to see the full potential of those bifi coils because of voltage division of each series bifi in series with the rest. But 'A' and 'B' doesnt have that problem. ;D I think this 'A' and 'B' way of winding motor coils might be a good thing. Will see.  ;)

And the circuit of coils as a whole will be the same resistance either way you do it. But that voltage difference between turns is not minuscule nor marginal. ;) There should be some kind of noticeable difference.

Mags


conradelektro

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #245 on: July 03, 2013, 09:42:22 AM »
@Gyula: the transistors you mentioned only cost 4 to 7 Cent, so I will order them.

@Mags: you might recall that Lasersaber's second 3D printed motor has 12 coils NSNS.... and 6 magnets on the rotor.

For your build that would mean 24 coils NSNS.... and 12 magnets on the rotor. Every second coil is connected in reverse. The action on the rotor magnets happens only between N S coils (not between S N coils), one coil pushing the other pulling.

But you might have different ideas?

Greetings, Conrad

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #246 on: July 03, 2013, 02:33:42 PM »
@Gyula: the transistors you mentioned only cost 4 to 7 Cent, so I will order them.

@Mags: you might recall that Lasersaber's second 3D printed motor has 12 coils NSNS.... and 6 magnets on the rotor.

For your build that would mean 24 coils NSNS.... and 12 magnets on the rotor. Every second coil is connected in reverse. The action on the rotor magnets happens only between N S coils (not between S N coils), one coil pushing the other pulling.

But you might have different ideas?

Greetings, Conrad

Hey Conrad

I realize those things.  We can use just as many mags(NSNS) as coils(NSNS) as long as we bias the reed with a mag so it only triggers on every other magnet pass, or the rotor will just bing bong left then right repeatedly. Having more magnets, just as many as there are coils, will provide more drive force than just half the number of mags vs coils.  ;)

Mags

DadHav

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #247 on: July 03, 2013, 03:34:46 PM »
Hello Mags, Conrad. Thanks for spending some time on the one coil circuit. I haven't digested everything you wrote yet but I will get to it as soon as I clear up some real life issues. I also haven't read all the posts on the LS motor but notice the 6 north out 12 coil configuration mentioned at the beginning of the thread. LS explains a push pull effect from the configuration. Makes perfect sense, right? After the initial pulse there is then a generated sine wave from the other six coils as the magnet then passes the coils along with something from the coils collapsing right? nsnsns equal poles and magnets etc will produce something allot different as well as a reed switch that doesn't know north from south, No? Bifiler with a transistor would only fire on one pole or half the magnets. Hmm with equal poles and coils as well as bifiler / transistor you mighe have all push or all pull. You could make a mini commutator disk with any small magnet configuration you need to work with the reed switch. Timing would be simple as well. I always wanted to do this for my window motor but never got around to it. Sorry I haven't been able to keep up with what's going on here. I'll try to read up so I can make some sense when I comment. Take care.
John Hav

TinselKoala

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #248 on: July 03, 2013, 06:22:27 PM »
@Mags: Thumbs up! I especially like the trim fasteners for bobbins.  I can't afford a spool of wire and I don't have the tooling here necessary to attain the precision required or I'd be joining you folks in your builds, I love a good pulse motor.
But I'm watching.... so good luck and continue the detailed reports please!

TinselKoala

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #249 on: July 03, 2013, 06:25:30 PM »
A unipolar latching Hall sensor like the one Sparkfun sells might do the trick. It turns hard ON with one polarity, stays on until it sees the opposite polarity then turns OFF, and has the open collector output so it can emulate the reed switch directly in the circuit. Maybe. They only cost a dollar, why not try one out. And the box that they mail them in is itself pretty neat.

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #250 on: July 04, 2013, 06:58:35 AM »
@Mags: Thumbs up! I especially like the trim fasteners for bobbins.  I can't afford a spool of wire and I don't have the tooling here necessary to attain the precision required or I'd be joining you folks in your builds, I love a good pulse motor.
But I'm watching.... so good luck and continue the detailed reports please!

Thanks. There are some out there that are oblong, of which he didnt have. I want the right side and the left side of the coils wires to be straight up and down as the magnet passes left and right. The round coils, only a small portion of the coil is perfectly vertical where as the magnet field cuts the windings to induce current. The more the windings are not being cut straight across by the magnetic field, the less that is induced. Like if the wires were wound around the outer perimeter of the rotor where the field is dragged along the length of the wire, current wont be produced in the windings, at least at the output. Like in commercial motors and gens, the field cuts a majority of the wire straight across and the loop backs at the ends of the armature windings that dont get straight crossings of the field or not in the field at all possibly, these areas of the winding are small in comparison to the straight runs through the armature coil as a whole in comparison to round coils. ;) Ill find those clips.

The wire is pretty cheap in my opinion. I think the 6700ft roll LS had shown was about $8.  My roll on ebay is 50,000 ft $35 shipped in 3days from Cali to Fl.

Mags

Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #251 on: July 08, 2013, 06:23:03 AM »
Making my stator ring from 1/4 in plexy. Found these black plastic spacers that Im using to hold the white bobbins. The 'barbed' shaft ends of the white door panel clips(bobbins) will be easier to change out being the inside of the black spacer is smooth. They were a tight fit at first, but as they sit in the spacers for a bit, they become looser, as they were a bit too tight. I dont want to have to apply too much force with these coils with the fine wire.
Going to mount some of the black spacers tonight and finish tomorrow. Then make stands for the stator ring and wind the coils.

These door clips I get 20 for $5 off the hardware truck. In a parts store, they want up to $15 for as little as 2. :o Crazy.  Unless you have a supply truck in town, best to order them online if some people want to go this route.

Will be winding single wire coils first, then Ill wind 24 more in bifi to compare. Should still have plenty of wire after both. 


Mags



Magluvin

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #252 on: July 09, 2013, 06:51:30 AM »
Got all the black spacers mounted. Will be getting more door panel clips when the truck comes by tomorrow. 20 per bag and need 24. Plus another bag for 24 bifi. Start winding coils tomorrow.

Mags

conradelektro

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #253 on: July 09, 2013, 10:19:05 AM »
@Mags: Your rotor, ring for the coils and base plate look professionally cut or turned? Did you have them made or do you have the right equipment?

Greetings, Conrad



TinselKoala

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Re: Has anyone seen Lasersabers new motor runs on 1000uf cap
« Reply #254 on: July 09, 2013, 12:55:11 PM »
Beauty.
You could even make a winding set like UFO's asymmetric fantasy mogen.

Just kidding.... that's looking very very nice, I am impressed.