Super Series R/R Market Survey

[ryonker]

To Measure Is To Know

This makes sense to me, and I am not that smart.

Thanks Pos!

Rick

[posplayr]

SCIENCE!

Thanks for checking all this, Pos. Now this all makes more sense.

So basically, it appears that using Compu-Fire R/R means about 10 less amps are wasted making heat in the stator. I like that. I like that a lot.

That is correct about the current, but what is more important is that with a FET SERIES R/R the stator has to dissipate nearly 3 times as much heat as with the Compu-Fire which is a SERIES R/R.

It is a little difficult getting at the power lost to heat when the SHUNT regulator shorts out (i.e. voltage goes to zero at the leads), but the current measurement should be accurate. So the calculations of total power are assuming 0.5 ohms of resistance which is about what I measured with an ohm meter. There is some reactance because I can see phase shift, but regardless we can make a accurate ratio assessment even if we don't know the absolute value of power.

For a Compu-fire SERIES R/R Power consumed in stator heat is 1/3 of the power consumed by the stator using a FET SHUNT R/R. This is the power and lack of cooling to the stator that causes the stators to fry.

There is additional power lost in heating the SHUNT R/R which is probably about 3 times the Compufire as well.

[Nessism]

Some interesting stuff there Jim. Thanks for putting this all together.

Unfortunately, my feeble mind doesn't understand a few thing: for one, the charging system is fed though a 15A fuse, so how come it doesn't blow if the stator produces 27A (I assume a normal stator produces a lower current but still above 15A)? Next thing I don't understand is how much power is used by the GS during normal running? It's been much discussed here how the GS charging system can barely keep up with itself, and can't cope very well with added running lights or heated clothing. If that's the case, how much extra current is the stator producing that needs to be shunted back into heat? I'm still trying to understand how much real world need there is for one of these R/R's if we are running a normal (not high output) stator.

[posplayr]

Some interesting stuff there Jim. Thanks for putting this all together.

Unfortunately, my feeble mind doesn't understand a few thing: for one, the charging system is fed though a 15A fuse, so how come it doesn't blow if the stator produces 27A (I assume a normal stator produces a lower current but still above 15A)?

15A is what comes out of the R/R. The 27 amps is what is running through the stator to generate the 15 amps. Anything in excess to the 15A is simply to generate heat to avoid sending it to the GS electical.

Imagine you want to dim the 120V lights in you office. So if you do it like a SHUNT R/R U would put two screwdrivers to your 120V wall outlet, if you momentarily short the screw drivers the lights will dim each time you touch the screw-drivers. The current is the wall climbs as it is a direct short. If it was not for the fuse box you would fry your wires in the wall.

In this analogy the house wiring is the stator
the screw drivers are the shunt R/R
the light is the GS load.

Next thing I don't understand is how much power is used by the GS during normal running? It's been much discussed here how the GS charging system can barely keep up with itself, and can't cope very well with added running lights or heated clothing.

Yes I have heard that as well. I think it is a mis perception due to low output at idle.

If that's the case, how much extra current is the stator producing that needs to be shunted back into heat?

Nothing needs to be shunted as was shown by the SERIES design. The minimum required is basically established by the SERIES regulator so anything the SHUNT is putting out above the SERIES is simply converted to heat. Approx 1.7 to 1 excess current and 3 to 1 excess power.

I'm still trying to understand how much real world need there is for one of these R/R's if we are running a normal (not high output) stator.

[/QUOTE]

Anyone burning up stators or having charging problems should get one. I would say by the time you burn up two stators you should definitely get one of these. Some might say after the first burnt stator

[posplayr]

Install instructions here..................

http://www.thegsresources.com/_forum/showthread.php?t=161397

SHUNT_vs_SERIES_RR_Compare_Tutorial

[posplayr]

Some interesting stuff there Jim. Thanks for putting this all together.

Unfortunately, my feeble mind doesn't understand a few thing: for one, the charging system is fed though a 15A fuse, so how come it doesn't blow if the stator produces 27A (I assume a normal stator produces a lower current but still above 15A)? Next thing I don't understand is how much power is used by the GS during normal running? It's been much discussed here how the GS charging system can barely keep up with itself, and can't cope very well with added running lights or heated clothing. If that's the case, how much extra current is the stator producing that needs to be shunted back into heat? I'm still trying to understand how much real world need there is for one of these R/R's if we are running a normal (not high output) stator.

Better explaination

SHUNT_vs_SERIES_RR_Compare_Tutorial

[ryonker]

Thanks for the more basic tutorial.

What does Mosfet mean again?

I noticed another guy selling R/R kits and it was the FHO12AA model but he called it a Mosfet type R/R.

http://roadstercycle.com/Universal%20Mosfet%20FH012AA%20charging%20system%20upgrade.htm

Thanks!

Rick

[Calvin Blackmore]

Is he related to bobafet?

[posplayr]

Thanks for the more basic tutorial.

What does Mosfet mean again?

I noticed another guy selling R/R kits and it was the FHO12AA model but he called it a Mosfet type R/R.

http://roadstercycle.com/Universal%20Mosfet%20FH012AA%20charging%20system%20upgrade.htm

Thanks!

Rick

A MOSFET is basically a high powered 3 terminal switch device. It is normally operated fully open or fully closed. He is still talking about a FH012A which is FET (or MOSFET) based SHUNT type. The plots I provided are of that MOSFET unit as compared to the Compufire.

The Compufire is SERIES

http://en.wikipedia.org/wiki/MOSFET

[bwringer]

Pos, I'm very shaky on the theory of all this, but do you foresee any issues with switching speed at higher RPM, like, say, 9,000 RPM?

In other words, does the Series regulator have a "speed limit" on how fast it can react?

[posplayr]

Pos, I'm very shaky on the theory of all this, but do you foresee any issues with switching speed at higher RPM, like, say, 9,000 RPM?

In other words, does the Series regulator have a "speed limit" on how fast it can react?

The 3 phase output frequency of the 18 pole generator is given by: (simple to derive from conversion factors and the 3 phases in 18 poles)

F_hz = RPM/10

So even at 10K RPM that is only 1Khz which is relatively slow even for power supplies. If switching was at 10-100K hz then there might be something to worry about.

Essentially there is nothing more stressing in terms of switching speed for the power devices and for control circuitry 1Khz is nothing