ST head modification for 48 volt battery charging

[mobile_bob]

Bruce:

your assumption would be exactly what i would expect,
here again i misunderstood what you had stated earlier and read it to be

      N

N           S

      S

which really wouldn't work out well at all, for the previously stated reasons, and
because even if it did work the sine wave would have a double positive going hump, followed by a double negative
going hump, with a opposing spike between the two sets of humps.

we are on the same page now i think




see folks this is what you get when you put an  EE in a room with a Mechanic 

lots of confusion and discussion 

still this has been an interesting discussion all in all, don't you think?

bob g

[Jedon]

Does all this pertain to other heads besides ST's? I have a 5400W 12 pole Lima on my SR2, the 12 poles should make it more configurable?

[mobile_bob]

is the lima a 3phase 12 wire head?
or is it a single phase 600rpm head?

my head hurts!



bob g

[Crumpite]

Bruce:

your assumption would be exactly what i would expect,
here again i misunderstood what you had stated earlier and read it to be

      N

N           S

      S

which really wouldn't work out well at all, for the previously stated reasons, and
because even if it did work the sine wave would have a double positive going hump, followed by a double negative
going hump, with a opposing spike between the two sets of humps.

we are on the same page now i think




see folks this is what you get when you put an  EE in a room with a Mechanic 

lots of confusion and discussion 

still this has been an interesting discussion all in all, don't you think?

bob g

Interesting and very helpful to those of us who had generator theory 30+ years ago...

Daryl

[Jedon]

Single phase 12 lead 1800 rpm

[mobile_bob]

gotta think about that one a bit, most 12 wire 1800rpm heads are three phase, but yours says single phase
so it could be setup as Y connected single phase, or maybe zigzag connected single phase.

hmmmm, gotta think about it, and my head hurts

bob g

ps. took another look, if it were three phase Y connected to pull off 120 single phase, it would have 208 and not 240 that is listed
so it is a different animal that i am used to seeing.

[Jedon]

208/2 = 104V, my house would be very unhappy at that voltage and I'm running off it right now... The Kill-A-Volt says 130V right now, the other circuit is probably at 114V

[mobile_bob]

sorry if i confused the issue

what i meant to state was if it were a three phase Y connected head, and had 120volt capability
it would have to have 208 also and not 240 across two legs, the 120 would be from each leg to neutral

so i am fairly certain your head is not three phase capable, just not sure why it is listed as a 12wire head

bob g

[bschwartz]

Bob, I just looked at the physical layout of the stator wiring.  I modified your diagram to show the physical wiring in my ST-5 head.  Wires labeled U1, U2, U5, U6 are factory labels.  Wires labeled X1, X2, X5, X6 are my designations where I cut jumpers and assigned my own.  You will notice the the jumpers cross the windings and are not physically next to each other.  I hope this may make a little sense and contribute to the understanding of these.

[mobile_bob]

thanks for posting that, and when you finish it would be of great importance to post some pictures
and sketches of the "as installed" connections, so that others might see exactly how it is supposed to be
connected based on what the chinese have provided to work with.

bob g

[Crumpite]

Folks

I just found a source for heavy duty insulating tubing as used in motor rewinding.

http://skycraftsurplus.com/sleevingtubing.aspx

Daryl

[bschwartz]

Holy cow!! Choices!!!  Now, which one should I use to wrap around the already heat shrink tubed wires before varnish?  I couldn't find shoe laces that were hollow like they used to be.

[wrightkiller]

    Look at this ....   http://www.parachute-cord.com/........OR

http://parachutecord.net/

[Apogee]

It will be interesting to see if flicker is reduced with the rewiring.

I was thinking about something else that would be an interesting experiment.  Although, there is nothing we can do about it...

If the poles are at 90 degrees and essentially creating an on, on, off, off scenario, I would think the flicker would be exaggerated when in sync with the combustion event. My theory is that it might be worsened by armature vs crankshaft/combustion event position.  Since most folks are running pulleys of different sizes, the timing position is always changing (the part we can't do anything about), but at some point, it might be worse in the "cycle" than other times. This could be happening so fast, that it might be difficult to perceive, as it would just be a stronger flicker than other times in the "cycle".

This might explain why other types of 60 hz generator heads seem to have less flicker.  However, I could be completely wrong about this, as I'm just guessing and it's 4:00am.

But, assuming an armature with 4 poles that are wired correctly, wouldn't it make sense that the waveform at the pole position 90 degrees out of phase with the combustion event would be the most uniform?  This way, when the generator poles are at their peak generating point, the cylinder would be at mid-stroke and not at the initial detonation point or the bottom of the stroke.  Both of those points are the extremes in the combustion cycle.  What I'm wondering is if it would reduce the spike on the waveform, and therefore reduce some of the flicker, by not having the peak generating point lined up with the most extreme power points in the engine cycle. Just brainstorming here...

Now combine the above theory with a genhead that is wired as on, on, off, off, and it would only exacerbate the problem.  At the point in the "cycle" when the max generating points are lined up with the combustion event, the max and min points in waveform would be even more extreme.

It would be a very interesting experiment to have crank position sensors on both the generator and engine, and write a program that would monitor both positions in relation to the output waveform and it's spikes.  Again, we can't do anything about it, short of either winding a head designed for slower rpm, or running the engine faster with the same diameter pulley on each.  But it would be very interesting to know the point in the cycle (if there is one) where the flicker is the least.

I can't imagine Lister sold the number of SOM units they did if all had the horrendous flicker problems that the ST heads seem to have.  The rural wives would have gone ballistic...  "Not tonight honey, the flicker is giving me a headache..."  You can bet ol Henry would have been talking to his SOM salesman say "John, we REALLY need to do something about this flicker, I haven't gotten any for MONTHS..."

Just my thoughts (as empty as they are at this time of the morning),

Steve

[mobile_bob]

Steve:

you have made a valid point/observation in my opinion

if i am not mistaken, most of the better direct drive generators such as from kohler
have the rotor keyed to the crankshaft, that way they can get the combustion event timed
to somewhere on the downhill slope of the sinewave going toward crossover where the surge
can be hidden for the most part.

they also used the anti flicker point set, this would mandate the use of a keyed rotor to crank
scheme or the points would never be in time with the flicker.

i am with you, we probably can't do much in this regard with a lister turning 650 and the gen turning 1800 or 3600
but i am thinking maybe the direct drive changfa's might benefit, even though their flicker doesn't seem to be as
pronounced to start with.  i guess given a choice one should try to time the genhead to the engine when assembling?

with the drive i have i can set the relationship between the two anywhere i want it, down to a degree or less in accuracy

might be interesting to do so and check the results with a scope to see if there is a noticeable change in what might be seen
as flicker.

this place is so good for questions, idea's and working on solutions

while i personally don't have an issue with flicker, because i don't plan on using the st head for lighting to start with, it certainly ought
to be something i test for, explore and try to document so that others might benefit or adapt for their useage?

thanks

bob g