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regulator/rectifier


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So With my new ricks stator and stock/original regulator I'm getting 14.3 volts at idle and it drops off to 13.7 as rpms increase. Holds at 13.7 even while using heated gear. I'm thinking of replacing with a mosfet regulator. I have a '97 xx. Recommendations for brand?

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Strange that the voltage drops, but since it holds with a load I guess it doesn't matter.  If you're looking to replace it because you think you need more than 13.7, don't bother.  If you're doing it because the drop has you thinking it's defective, I'd first test to see if the drop is coming from the stator.

 

I don't have a brand suggestion, but if I needed a new one I'd probably go with a series regulator instead.

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FH020AA, buy it here   http://www.roadstercycle.com/index.htm  

This is what I used in "superkit" form, comes with all the wires ready to go.  Requires a small amount of fab work as unit is slightly bigger than stock. No complaints at all.

 

"I don't have a brand suggestion, but if I needed a new one I'd probably go with a series regulator instead".  Per superhawk996 suggestion, that would be the SH847 regulator. Even better, slightly bigger again, requiring slightly more fab work to fit. 

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I find it hard to believe there is a stock '97 R/R still working.  Probably won't work for long with the output you're measuring.  I would go series as well, but the Yamaha is a good unit, too.

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On 10/5/2020 at 10:58 AM, The Krypt Keeper said:

Go with a series regulator over mosfet if you can. 

 

 

 

 

Why? Just an honest question.

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8 minutes ago, RXX said:

 

 

Why? Just an honest question.

 

Since I'm not sure whether you don't know how each work, or don't know why one method is preferable to the other, here's a short version of a long story...  Regular shunt-type regulators just dump excess power to ground.  The excess energy is wasted as heat.  A series regulator interrupts the output of the alternator when it is not needed, so there's less heat and less power wasted.  On a large bike the power makes no difference.  The theoretical advantage for series is that they should last longer since they don't get hot.  I disagree.

 

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2 hours ago, SwampNut said:

  The theoretical advantage for series is that they should last longer since they don't get hot.  I disagree.

 

Could you elaborate please? every time I think I have a grasp of how motorcycle charging systems work I learn something that makes me doubt what I thought I knew.it seems to me a series regulator should also reduce the operating temperature of the stator assuming you're not drawing full capacity of the system.I suppose it's possible that the voltage of an unloaded stator might rise high enough to endanger the insulation of the stator coils but that doesn't seem likely assuming the insulation is healthy.

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Yes, the stator should run cooler, and you might gain around 1/2 HP.  I don't remember the actual HP gain potential, but not much.

I too have a little reservation about high voltage and the insulation.  It would be interesting to see if the stator output voltage is significantly different when it's disconnected from the R/R, that would be the highest it can get.

 

The series regulator should run cooler and most people believe that heat is what kills the shunt type so in theory the series 'should' last longer.  I understand how they work as far as what happens, Carlos knows a lot more about electronics so he'll know more about how it happens.  I assume the longevity of a series regulator will hinge on the quality of the stuff in them so even with the reduced heat it could have a short life if it's not well made.  I imagine that the magical stuff regulating the 50+ volts AC is more complex in a series vs. shunt meaning that there may be less room for error in them.

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How does this result in a theoretical gain in horsepower? The stator is always producing current as ling as the motor us running, correct? 

 Why would the stator run cooler?

Edited by XXBirdSlapper
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1 hour ago, XXBirdSlapper said:

How does this result in a theoretical gain in horsepower? The stator is always producing current as ling as the motor us running, correct? 

 Why would the stator run cooler?

A series regulator 'unloads' the stator so it's consuming and creating less power that would just be turned into heat.

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21 hours ago, joblock said:

it seems to me a series regulator should also reduce the operating temperature of the stator assuming you're not drawing full capacity of the system.

 

It probably does, and you're also correct about the potential voltage issues (hah, potential, get it?).  I just don't believe there's a true benefit, and that's purely an opinion without hard data to back it up.  I believe it's mental masturbation to discuss it at all, which is fine, but in reality I just don't think giving the topic any thought at all has any actual benefit.

 

15 hours ago, superhawk996 said:

I don't remember the actual HP gain potential, but not much.

 

1 HP = 746 watts, so yeah, basically nothing at all to gain.  It would matter on a 50cc bike.

 

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1 hour ago, superhawk996 said:

A series regulator 'unloads' the stator so it's consuming and creating less power that would just be turned into heat.

But the electrons are still "excited" by movement of the magnet regardless of how the regulator controls voltage down stream right?

 How is the stator consuming power?

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42 minutes ago, XXBirdSlapper said:

 

 How is the stator consuming power?

My rake is that it is not.

3 phase of windings. Connected to ground at one end. The other end of each connected to a series circuit, that opens the current path.

Power equals current × voltage. Remove current, or voltage, and you have no power to consume.

Shunt regulators are simple devices, scaled to the loads required.  We screw up by reducing the loads with lower wattage lamps, or higher wattage heated gear.

 

Regulator technology has changed in the 20+ years since the XX was designed.

Edited by redxxrdr
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Just spinning an *automotive* alternator wastes power due to friction, and has an impact on RPM changes due to inertia.  The actual power needed to produce the electricity could be lower than the friction loss.  In any case, it's very little.  Car alternators are under 60% efficient.  So let's just call it 400 watts per HP.  That means a typical car alternator only uses 3-4 HP at FULL output.  Some of which is lost to friction anyway.

 

I don't think the motorcycle alternator takes any energy to simply spin, so the only power would be the magnetic drag.  With an open stator, there would be nearly no magnetic drag.  Voltage is potential, not power.  You could generate ludicrous voltage from very little power.

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19 minutes ago, SwampNut said:

It would matter on a 50cc bike

With a BB size stator.

 

I think the biggest benefit would be a longer lasting stator, assuming that keeping it cool makes it last longer.  I recently read about some bike that had stator life problems, they increased oil flow to it and that apparently solved it.

 

My bike has CF case covers so it's probably suffering a little extra heat.

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16 hours ago, XXBirdSlapper said:

But the electrons are still "excited" by movement of the magnet regardless of how the regulator controls voltage down stream right?

 How is the stator consuming power?

I don't know how to explain it and I might be wrong, but I believe that creating current (feeding a load) changes the 'pull/push' against the magnet as it passes over the windings.  Just exciting electrons that aren't being consumed should (if my theory is correct) result in very little power consumption.  It's possible that just moving the magnet across the windings takes XX amount of power regardless of electrical load on the windings, but if that's the case it means that the temperature of the stator would also be the same regardless of load.

 

Carlos or someone else might know better.

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The stator consumes mechanical power and produces electrical power. 

The ability of the series type regulator to unload the stator during periods of low electrical demand from the bike would be similar to maintaining speed down a steep hill by being able to close the throttle. 

Using this analogy, regarding the old shunt style regulator, going down the same hill while leaving the throttle open requires application of the brakes to maintain speed. 

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It's this simple:  Energy can neither be created nor destroyed.

 

You can convert energy between motion, heat, light, electricity, etc.  A magnet moving over a coil has the potential to convert motion into electricity (and due to resistance, also heat).  If energy is taken from the coil to be converted again, say into light in the headlight, then energy must be converted from mechanical to electrical.  If no energy is being used, then none can be converted.  Notice how a generator has to apply more gas when a load is on, and very little when a load is off.  This is not very different from the vehicle alternators.

 

A bike has a permanent magnet stator-type alternator, cars have an excited field alternator.  I'm not sure what's in a gasoline generator, probably excited field, but don't know for sure.  The permanent magnet means there's probably SOME amount of added residual loss when it's spinning with no load.  So there's a difference, but I believe it's very small.  I don't know that to be an absolute fact.  Any motion energy being used when the stator is open would have to be converted to heat, there's no other load.  But I don't see how anything more than a very small amount of energy could be used in this case.

 

All of this is simplified because we're not trying to re-examine the laws of thermodynamics or physics.

 

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