Regulator/Rectifier pack

On 22 Jul 2004 20:38:27 GMT, kaybearjr.DeleteThis@aol.comical (krusty kritter)
wrote:

  >>From: Ovenpaa tagmignu*FOS*@tiscali.co.uk
 >
  >>I have a 500 cc Rotax engined bike that has (I assume!!) a 12 volt 3 wire
 >generator system the wires are colored white orange and green.
 >
 >Ovenpaa tagmignu? What is that, Cymric?
 >

<snip>

Thank you for such a comprehensive reply, it looks like
a wye type generator, however it is late and dark here so I will check
this weekend.

Ovenpaa is Danish for 'on top' (long story) tagmignu is also Danish
as I am married to a Dane we tend to use a mixture of English and
Danish words here )

I am told that some of that some of the guys here are using NiCads
instead of LA type cells, I thought the charging circuit would be
different but they tell me a standard charging circuit on a 'bike
works, is this the case?
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 >From: Ovenpaa tagmignu*FOS*@tiscali.co.uk

 >Ovenpaa is Danish for 'on top' (long story) tagmignu is also Danish as I am
married to a Dane we tend to use a mixture of English and Danish words here )

I'm descended from Danes, Germans, Saxons, Irish, Scots, etc...

Mother never talked much about Grandma, but she did mention casually that
Grandma was Danish, married a German, and lived in Iowa, USA...

 >I am told that some of that some of the guys here are using NiCads instead of
LA type cells, I thought the charging circuit would be different but they tell
me a standard charging circuit on a 'bike works, is this the case?

It should be no problem to charge a NiCad with a motorcycle charging system, as
long as it produces a few more volts than the battery puts out...

When you say "NiCad", the first thing that comes to mind is rechargeable
flashlight batteries that contain the sodium hydroxide in paste form...

But there are flooded-cell NiCad batteries too, they are used all over, in
aircraft, railroad crossing signals, etc...

I suppose there are a lot of railroad signals that don't work over there in the
UK and a bunch of riders are happy with their "free" batteries

I worked on NiCad batteries in the Air Force at Edwards AFB, a long, long time
ago. They were "high tech" and we really took good care of them, in a special
section of the battery shop...

One difference between a flooded cell LA battery and a flooded cell NiCad is
that the LA battery produced 2.2 volts per cell, but the NiCad only produces
1.8 volts per cell, so you need more cells...

The expen$ive NiCads used in airplanes have individual replaceable cells with
jumper straps that are fastened between cells with nuts. The case that the
NiCad cells sit in is a separate plastic case that might contain sodium
hydroxide crystals from the electrolyte which might have leaked from one or
more cells...

One time my boss told me to disassemble a NiCad
battery and wash out the sodium hydroxide crystals with water. He said, just
put your hand in the water and stir up that white stuff and dump it out and
flush the case out...

So I did what he said and got sodium hydroxide solution up under my
fingernails, and that really hurt, I had to cut my fingernails and scrape that
stuff out of my skin to stop the burning sensation...

Another difference between LA batteries and NiCads is that deep cycling most LA
batteries down to zero volts will probably kill the battery, it will sulfate...

But NiCad batteries actually *need* to be recycled down to zero volts by
discharging the battery through a load, and then jumpering across each cell's
positive and negative terminals until the voltage is zero...

Then when the battery is recharged, it will take a full charge. If you *don't*
deep cycle a NiCad battery regularly, you don't know what it will do, if it
will roll over and play dead at the worst possible time, like when you're
trying to restart your jet engine after a mid-air flameout...

For instance, I was assisting the crew chief on a T-33 jet
trainer, and we were starting the jet engine using a mobile generator set.
Halfway through the start sequence, with ignition on and jet fuel being sprayed
into the burner cans and burning in there, the mobile generator set suddenly
quit, the starter stopped turning, kerosene smoke was coming out both intake
and exhaust of the engine and the crew chief told me he'd have to try to start
the engine by cranking it with the NiCad battery, and he hoped that the NiCad
had enough "juice" to get the engine started before the fire inside got too bad
and he'd have to use the fire extinguisher on it...

That's when I first heard about the NiCad "memory" problem. If you only
half-charge a NiCad, it "remembers" that, and next time it will only take half
a charge...

And, wait until it's dark to go to "midnight auto supply" down by the railroad
tracks



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Ovenpaa <tagmignu*FOS*@tiscali.co.uk> wrote:
 >
 > Can anyone refer me to an online schematic of a typical wiring
 > diagram, I prefer not to use a battery and this is an enduro type
 > machine.

<a style='text-decoration: underline;' href="http://www.electrexusa.com/electrex_fault_finding.html" target="_blank">http://www.electrexusa.com/electrex_fault_finding.html</a>

Not using a battery may be a problem; From what I've seen
the battery plays an obscure but crucial role in making
the regulator work correctly. It's possible that a _very_
large capacitor could be substituted, but I get the impression
that modern RR's are in some way dependent on having a
battery with the right dynamic impedance in the circuit.

The Electrex website is the best I know of. Good luck,

bob prohaska<!-- ~MESSAGE_AFTER~ -->
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 >From: bob prohaska bp RemoveThis @imln8.berkeley.edu

 >Not using a battery may be a problem; From what I've seen the battery plays an
obscure but crucial role in making the regulator work correctly.

An excited field alternator can get away with using a very weak, almost dead
battery, if it produced just enough juice to initially excite the alternator
field and produce enough magnetic flux density to produce more electrons...

The excited field alternator starts out with a certain amount of residual
magnetism in the pole shoes and can "bootstrap" itself from extremely low
voltage to operating voltage...

But a permanent magnet alternator has already got all the magnetic lines of
force it's ever going to have, whether it's turning, or standing still...

It's going to produce all the current it possibly can, according to the amount
of flux density, the number of turns in the windings, and the RPM the rotor is
turning...

The typical lighting load on a motorcycle is only about 100 watts, and the
typical permanent magnet alternator produces something like 300 to 400 watts...

So, what's an electrical system to do with 200 to 300 watts surplus that the
lighting system can't radiate as heat?

You can burn some of the excess juice up as heat, with a shunt type regulator.
Ignorant riders think there's something *wrong* with their regulator when the
heat sink case gets up to 105 degrees F...

What else to do with the excess juice? Why, send it to that fat plastic cube
under the seat, and let the *battery*
radiate it as heat, while boiling the electrolye and making little hydrogen
bubbles...

So the battery becomes a sort of "heat sink" just like the finned case of the
rectifier regulator unit...




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krusty kritter <kaybearjr DeleteThis @aol.comical> wrote:
 >
 > The excited field alternator starts out with a certain amount of residual
 > magnetism in the pole shoes and can "bootstrap" itself from extremely low
 > voltage to operating voltage...

Perhaps more important, it can "throttle down" its output to match the load.

 > But a permanent magnet alternator has already got all the magnetic lines of
 > force it's ever going to have, whether it's turning, or standing still...
 >
 > It's going to produce all the current it possibly can, according to the amount
 > of flux density, the number of turns in the windings, and the RPM the rotor is
 > turning...
The not-so-intuitive detail is that "all the current" is fixed by the
self-inductance of the stator windings, and depends very little on speed
and load when working as designed.

 >
 > So, what's an electrical system to do with 200 to 300 watts surplus that the
 > lighting system can't radiate as heat?

If the RR is working right, the regulator section is supposed to short the
stator cleanly, dissipating power equal to the stator current times the RR's
internal voltage drop, which _isn't_ 12 volts. In principle it should be 1.4
volts (SCR forward drop), I've measured about 2 volts. The "missing" voltage
appears across the stator inductance, which isn't dissipative and makes no
heat. The energy is just stored until the next cycle.

 > You can burn some of the excess juice up as heat, with a shunt type regulator.
 > Ignorant riders think there's something *wrong* with their regulator when the
 > heat sink case gets up to 105 degrees F...
I'd be delighted if my vfr's rr only got to 105 F; Did you possibly mean C?

 > What else to do with the excess juice? Why, send it to that fat plastic cube
 > under the seat, and let the *battery*
 > radiate it as heat, while boiling the electrolye and making little hydrogen
 > bubbles...
 >
 > So the battery becomes a sort of "heat sink" just like the finned case of the
 > rectifier regulator unit...

That may in fact be what happens, but it can't possibly be intentional on the
part of the designers. Gassing batteries don't regulate accurately and dry
out fast. It's a destructive mode of operation.

If anybody's still curious, there's a webpage attempting to describe PM
charging systems in mechanical analogy at
<a style='text-decoration: underline;' href="http://imlpld1.berkeley.edu/~bob/mc/vfr/alternator.html" target="_blank">http://imlpld1.berkeley.edu/~bob/mc/vfr/alternator.html</a>

bob prohaska<!-- ~MESSAGE_AFTER~ -->
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On Mon, 26 Jul 2004 03:33:14 +0000 (UTC), bob prohaska
<bp.RemoveThis@imln8.berkeley.edu> wrote:

 >krusty kritter <kaybearjr.RemoveThis@aol.comical> wrote:
  >>
<huge snip>

Well thanks to both of you guys for a very informative brief, I found
it very informative, and it reminded me of many happy hours in
lectures. I must admit that I was an electrical engineer in my earlier
years however my background was industrial robotics and this was left
for a far more boring career (I saw the light and jumped to something
I enjoy about 6 years ago)

The resistance between the windings shows as 1.6 ohms, and open
circuit to ground, it is 3 wire only and must be a Wye wound device,
hopefully I will start wiring later this week.

I have opted for 10 X 1.2 volt nicad cells (as used by the kids for
electric r/c cars) they should do the trick, however if I am wrong
please shout now! The advantage of such cells is they can be
manipulated to fit the space available, in this case in a space to
the top rear of the air box, so it will be well ventilated and will
solve space issues.

I am looking for a solution for the front brake switch, it has to be
mechanical and waterproof and the brake is cable operated, obviously
proximity switching would be ideal, however I need to keep the circuit
as simple and as robust as possible. So any suggestions will be
gratefully received.

Well it is dark here, have a good evening.

/d



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The thing that makes the crowbar (shorted winding) regulator work, is
the mutual inductance, between the windings. You can sort one or two
windings, and saturate the core, or put it nearer saturation, and the
trio will put out less voltage and current, effectively limiting the
charging voltage.
Of my 4 Suzukis, the 76 had a controlled current rotor, with slip
rings, regulated with the typicle vibrating relay type regulator.
The 78 had one alternator winding crowbared with an SCR, my 80 had two
wires crowbared, and my 82 had two crowbarred. This approach is
necessary with a permanant magnet alternator. One could use a zener,
but it would have to be a boat anchor, with a huge heat sink. I've
heard some old Brit bikes were done this way, but there's no reason
with modern electronics.
My 97 Honda had a solid state regulator controlling the rotor current,
as did my three BMWs, a 94, 95 and an 01.
The other approach is to have barely enough alternator capacity to run
the bike with the lights on, and little left for the battery --
unregulated. In the days with switched kights, it was common to switch
off one winding, when turning the lights off. Both my 76 Suzuki, and
my 78 were like this. .

By the way, these windings can be in delta or wye configuration, from
the outside, they look the same.
Early Delco sealed batterys would occasionally blow up, if they had an
out of controll alternator driving them. It usually happened about 80
volts. Acually, the probably still do.
Dan
 >> Stay informed about: Regulator/Rectifier pack 

 >From: Ovenpaa tagmignu*FOS*@tiscali.co.uk

 >I have opted for 10 X 1.2 volt nicad cells (as used by the kids for electric
r/c cars) they should do the trick, however if I am wrong please shout now!

I had a radio controlled airplane, until about two weeks ago, when it got run
over by a semi truck on the Interstate as a powerful gust of wind blew it out
of the back of my pickup truck My tie-downs were totally inadequate for
the wind velocity...

The transmitter had a bunch of NiCads, all shrunk-wrapped together, but the
charger for all those cells probably only produced a few hundred milliamps, not
200 to 300 watts like a motorcycle permanent magnet alternator does...

Bob P. and others, and I have been discussing the characteristics of the
permanent magnet alternator for years now. A PM alternator produces *current*
based upon the strength of its magnetic field, the number of windings in the
coils, and the *frequency* of conductors cutting the line of magnetic flux,
based upon RPM and the number of pole pairs...

Bob P. is right that the inductive reactance of the coils is going to increase
with RPM, and I believe that the electrical engineers who have rated their PMA
at some given output wattage have chosen some RPM known only to themselves...

But the PMA is a sort of Pit Bull of the electrical world. If it's turning,
it's generating electricity, and it will attempt to carry any overburdening
load, or attempt to burn up any load that is too small to do battle with it...

Sounds like you might need about 12 NiCad cells to get the battery up to
compare to a lead acid battery that is fully charged at around 13.8 to 14.5
volts...

1.2 volt Nicad cell doesn't tell me much. What is the ampere hour capacity of
each NiCad cell? A motorcycle will typically have a battery with 8 to 12 ampere
hour capacity, meaning that the battery will deliver 8 to 12 amperes for an
hour without having the voltage drop off below 12 volts...

And, if the total number of cells forms a battery capable of producing enough
voltage to make the alternator work for a living, it will stand a chance of
surviving the continual excess current being shoved its direction without
getting really, really hot, and blowing up...

Your experiment is very interesting, but it sounds like it could be rather
expen$ive if you are mistaken about what
the AH capacity of the total battery should be, and what the current capacity
of the RR unit needs to be...

Good luck...


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Ovenpaa <tagmignu*FOS*@tiscali.co.uk> wrote:
 >
 > I have opted for 10 X 1.2 volt nicad cells (as used by the kids for
 > electric r/c cars) they should do the trick, however if I am wrong
 > please shout now! The advantage of such cells is they can be

That's what Baja Designs uses in some of their dualsport kits; should
be ok. As Krusty pointed out, however, a lead-acid battery has the
ability to gracefully (or, at least unspectacularly) cope with overcharge.
Not so sure about those little sealed bombs
 >
 > I am looking for a solution for the front brake switch, it has to be

Probably the easiest thing is to visit a junkyard and find a brake
lever assembly which has a switch built in. No doubt you could craft
a switch mount on the existing lever but I bet that would be more work.

Good luck!

bob prohaska<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Regulator/Rectifier pack 

bob prohaska wrote:

 > Ovenpaa <tagmignu*FOS*@tiscali.co.uk> wrote:
 >
  >>I have opted for 10 X 1.2 volt nicad cells (as used by the kids for
  >>electric r/c cars) they should do the trick, however if I am wrong
  >>please shout now! The advantage of such cells is they can be
 >
 >
 > That's what Baja Designs uses in some of their dualsport kits; should
 > be ok. As Krusty pointed out, however, a lead-acid battery has the
 > ability to gracefully (or, at least unspectacularly) cope with overcharge.
 > Not so sure about those little sealed bombs

Seems like it would be a simple matter to just make something like a
relay to open on battery over voltage conditions. Kind of retro 1930s
mechanical style regulators that everyone could understand and adjust.<!-- ~MESSAGE_AFTER~ -->
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On 27 Jul 2004 01:41:28 GMT, kaybearjr.TakeThisOut@aol.comical (krusty kritter)
wrote:

  >>From: Ovenpaa tagmignu*FOS*@tiscali.co.uk
 >
  >>I have opted for 10 X 1.2 volt nicad cells (as used by the kids for electric
 >r/c cars) they should do the trick, however if I am wrong please shout now!
 >
 >I had a radio controlled airplane, until about two weeks ago, when it got run
 >over by a semi truck on the Interstate as a powerful gust of wind blew it out
 >of the back of my pickup truck My tie-downs were totally inadequate for
 >the wind velocity...
 >

Ouch!

<snip>


 >1.2 volt Nicad cell doesn't tell me much. What is the ampere hour capacity of
 >each NiCad cell? A motorcycle will typically have a battery with 8 to 12 ampere
 >hour capacity, meaning that the battery will deliver 8 to 12 amperes for an
 >hour without having the voltage drop off below 12 volts...
 >
 >And, if the total number of cells forms a battery capable of producing enough
 >voltage to make the alternator work for a living, it will stand a chance of
 >surviving the continual excess current being shoved its direction without
 >getting really, really hot, and blowing up...

Yes, I think 12 cells is the best solution, they are 2200mA so overall
ampage will be low, however it will act as a buffer only for the
circuit, and maintain the horn and parking lights for a brief period.
 >
 >Your experiment is very interesting, but it sounds like it could be rather
 >expen$ive if you are mistaken about what
 >the AH capacity of the total battery should be, and what the current capacity
 >of the RR unit needs to be...
 >

My son has 'volunteered' the cells as he has moved onto noisy little
I/C engines now, we have abused them before with a home made charger
and they ran well, l run with the lights on at all times as a safety
feature so this may keep well keep excessive charging down slightly.
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 >From: Ovenpaa tagmignu*FOS*@tiscali.co.uk

 > My son has 'volunteered' the cells as he has moved onto noisy little I/C
engines now, we have abused them before with a home made charger and they ran
well,

When I noted that your experiment could become very expen$ive if you're wrong
about the alternator and the RR, that's what I was thinking about. I suppose
the stator for you alternator will cost about $200~$300 USD to replace if you
blow it up, and the typical aftermarket replacement RR costs over $100 USD...

By comparison, single NiCad cells for RC cars don't cost much...



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On 28 Jul 2004 02:42:13 GMT, kaybearjr.TakeThisOut@aol.comical (krusty kritter)
wrote:

  >>From: Ovenpaa tagmignu*FOS*@tiscali.co.uk
 >
  >> My son has 'volunteered' the cells as he has moved onto noisy little I/C
 >engines now, we have abused them before with a home made charger and they ran
 >well,
 >
 >When I noted that your experiment could become very expen$ive if you're wrong
 >about the alternator and the RR, that's what I was thinking about. I suppose
 >the stator for you alternator will cost about $200~$300 USD to replace if you
 >blow it up, and the typical aftermarket replacement RR costs over $100 USD...
 >
 >By comparison, single NiCad cells for RC cars don't cost much...


Heh, with my son as sponsor for the cells they are very cheap indeed,
I will choose to forget who paid for them initially.

Well I have just discovered a damaged inlet stub, it is basically a
rubber tube and is under $8 however it is two weeks away, I needed a
new angle adjuster for the carb anyway, so the Nicad trials are put
on hold until the spares are fitted, as the machine is for winter
training in anticipation of next years trip to Nordkapp I guess this
is no hardship, and it gives me time to continue with things like
fitting brake switches and lock wiring bits (I always find machine
preparation very satisfying and relaxing)

I will keep you posted on what happens.

Thanks again for your input.


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