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Regulator / Rectifier

Started by mshowe, August 27, 2015, 12:00:26 PM

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mshowe

I recently put a new stator from Rick's Repair and a new OEM R/R.  I can't remember where I got the R/R, but it's new.

Anyway, is there a better R/R I should install/use?  If so, please provide the details.

Thank you.
1981 Honda XL 125S
1983 Yamaha Vision
1993 Yamaha Venture


fret not

The main issue with using a Polaris RR unit is you have to get or make up the "pig tails" for connecting it.  This makes the MOSFET units for the various Hondas a bit more accessible since they (some models) come with "pig tails" like the Vision RR unit, though you have to change the terminals to fit your wiring harness.  Does anyone know if the Polaris RR unit uses "pig tails", or if the wiring harness plugs directly into it?
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

vl5150

I'm doing my R/R soon.  I picked up a used Polaris sh775ba on ebay for $50 and a Triumph pigtail for $10.  So not bad for $60. 

Part of my plan is to relocate the R/R to get it in the airflow so I'll post what I end up doing.

pinholenz

Have a look at this thread for suggested donor bikes with Mosfet R/R's

http://ridersofvision.net/rovforum/index.php?topic=14447.0
Only one '82.5  eXtreme Zen 550

George R. Young

Quote from: vl5150 on September 09, 2015, 08:51:17 AM
. . . . Part of my plan is to relocate the R/R to get it in the airflow so I'll post what I end up doing.
Even though the SH775 is an SCR regulator, it runs pretty cool because it only conducts as needed, unlike the shunt wonders. On the SV650S, it runs warm to the touch, not hot.

pinholenz

Good news about this Series type regulator as a cheaper (better?) alternative to the Mosfet regulators. Please keep us up to date as to how it goes.
Only one '82.5  eXtreme Zen 550

devotee

You guys are killing me. I've been following this thread a while. OK, I haven't been around much for 3 years, but when I put things back together, I found I was low voltage and bought another regulator/rectifier. Too bad for me as the new one put out 15.5 Volts at idle and + 17 Volts at about 4k rpm. It was a  NEW VOLTAGE REGULATOR FITS YAMAHA RXV 1000SE XV VIRAGO 700 750 920 1000 XZ VISION 550 4X7-81960-A0-00
Sold by: Rareelectrical
$79.66
Well at least they have a no questions return policy.
In the meantime I went stock and have acquired a NOS Yamaha reg/rect for my Vision.
The series rectifier is intriguing, but I'm a bit of a skeptic. Seems correct, but I want to know the series system will protect the R/R and coil before I switch.

devotee
XZ550RK
XS750E
GL1000 (1976) project

fret not

It would be nice for someone with a solid understanding of things electrical to explain how these things really work, but in the meantime until someone shows up I will try to 'splain' what I think I understand.

The shunt type of RR operates by demanding full generation from the stator at all times and shunts all excess electricity to ground.  All this energy goes through the RR unit, which feeds to the battery but protects the battery from boiling over by allowing only enough current to charge the battery.  The rest of the generated electricity is diverted (shunted) to ground via silicon diodes and the RR unit gets hot.  So does the stator.

The series type RR unit senses the condition of the battery and draws only enough current from the stator to satisfy the demand of the battery.  No excess current being generated, or shunted to ground.

If you have used a portable generator you will recall that when you  turn on a demand (lights, power tools, etc.) the generator surges a bit from the new load before it smooths out.  This is because when you draw off current it demands more from the stator, and it takes more horsepower from your motor to do this.  So, it stands to reason that a series RR unit should free up some normally otherwise engaged horsepower.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

pinholenz

And just to add my 2 cents worth; Although a Mosfet R/R is a logical upgrade from an older diode based shunt R/R, a Mosfet IS still a shunt R/R. The reason it is better than a diode based R/R is that it does the same shunting job with transistors rather than diodes. The nett result is that it is more reliable. Crucially for us, because it is more efficient, it does not heat up to the same degree and the critical components do not break down with age.

In theory the Series type R/R should be an improvement over both of these shunt R/R's

Quote from: fret nut on September 11, 2015, 01:22:45 AM
It would be nice for someone with a solid understanding of things electrical to explain how these things really work, but in the meantime until someone shows up I will try to 'splain' what I think I understand.

The shunt type of RR operates by demanding full generation from the stator at all times and shunts all excess electricity to ground.  All this energy goes through the RR unit, which feeds to the battery but protects the battery from boiling over by allowing only enough current to charge the battery.  The rest of the generated electricity is diverted (shunted) to ground via silicon diodes and the RR unit gets hot.  So does the stator.

The series type RR unit senses the condition of the battery and draws only enough current from the stator to satisfy the demand of the battery.  No excess current being generated, or shunted to ground.

If you have used a portable generator you will recall that when you  turn on a demand (lights, power tools, etc.) the generator surges a bit from the new load before it smooths out.  This is because when you draw off current it demands more from the stator, and it takes more horsepower from your motor to do this.  So, it stands to reason that a series RR unit should free up some normally otherwise engaged horsepower.
.

What I don't understand is how the demand on the stator can be altered to free up energy for the engine. My rudimentary understanding is that the Stator has no sensor to regulate what the demand is. In other words, it just works flat out all the time.
Only one '82.5  eXtreme Zen 550

vl5150

I do agree that a Mosfet R/R will help with the reliability of the R/R itself, but won't help the stator problem.  The one I ordered (Sh775BA) is a series R/R. and Triumph has the pigtail for it that I'll be cutting one side from and soldering.  It's in the mail at the moment so hopefully I'll get it today for a nice weekend project.

Ken Williams

You previous posters seem to have a good understanding of the subject. 

Alternating phase voltage is generated in the stator as the engine spins magnets imbedded in the rotor.  If the stator leads are connected to something that conducts current, current will flow between the leads.  With a shunt RR, stator leads are always electrically connected so AC currents are approximately equal with the engine running, regardless of battery charge.  When the system needs current to run the lights and ignition or charge the battery, stator currents are rectified to DC and directed to the positive battery terminal.  Current then flows through the system to ground and back to the stator.  When battery voltage is adequately high, additional current is not required.  Under these conditions, stator currents bypass the positive battery terminal and are connected directly to ground, therefore not charging the battery. 

With a series RR, charging works identical to the shunt type.  However, when battery voltage is adequately high, the electrical connection between the stator leads is broken until more charging current is required.  That is, currents do not flow in the stator unless required to maintain battery voltage. 

A MOSFET shunt RR should be more reliable than the legacy type.  Less power will be dissipated in the modern RR since the newer semiconductors have lower on resistance.  Thus it should run less hot. 

A series RR should improve stator life via lower temperature since current flows only when it is needed for charging.  The series RR should run cooler than the shunt type since less current typically flows through it. 

devotee

Ken Williams said: "A series RR should improve stator life via lower temperature since current flows only when it is needed for charging.  The series RR should run cooler than the shunt type since less current typically flows through it.  "

Seems logical. For now I'm beginning to understand that the stator heat produced (generated by I2R and eddy currents) with a shunt type is basically a function of engine rpm (and load current?).

In a series type R/R setup the regulator creates enough series resistance so that the output is nominal 14 to 14.4 Volts. It would seem like the stator would nearly always run cooler if the AC currrent is a function of DC load. Seems like it should be, but I'm trying to connect with some industrial motor/generator types to ascertain that that is the behavior of a spinning magnet generator.
devotee
XZ550RK
XS750E
GL1000 (1976) project

fret not

"What I don't understand is how the demand on the stator can be altered to free up energy for the engine. My rudimentary understanding is that the Stator has no sensor to regulate what the demand is. In other words, it just works flat out all the time."

This is true of the shunt type RR units, but the series draws only what the system demands, which is much less than full generating capacity.  It takes horsepower to generate current, and the more current you generate the more power it requires.  If you use a series RR unit you should be generating much less (nothing shunted to ground) current, so less demand on the engine power, therefore more is available for the rear wheel.  This may be pure conjecture as I have never actually seen an electron. ;)
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

The Prophet of Doom

#14
Quote from: pinholenz on September 11, 2015, 03:36:18 AM
And just to add my 2 cents worth; Although a Mosfet R/R is a logical upgrade from an older diode based shunt R/R, a Mosfet IS still a shunt R/R. The reason it is better than a diode based R/R is that it does the same shunting job with transistors rather than diodes. The nett result is that it is more reliable. Crucially for us, because it is more efficient, it does not heat up to the same degree and the critical components do not break down with age.

In theory the Series type R/R should be an improvement over both of these shunt R/R's

What I don't understand is how the demand on the stator can be altered to free up energy for the engine. My rudimentary understanding is that the Stator has no sensor to regulate what the demand is. In other words, it just works flat out all the time.
Here's an experiment to try.  Make sure you have a decently charged battery, turn your lights off, start your bike and let it idle.  A really low idle.  Now turn on high beam.  What happens? your bike stops right?

People are always saying that the stator is running full blast at all times - either delivering power to devices on the bike, or back to the stator (where it becomes heat) and robbing a good few HP in the process.  Now if your stator was running full blast all the time, then turning on high beam shouldn't have stopped the engine because it shouldn't have changed the load.


The full tits theory is a common misconception.  Truth is you can put the stator into a dead short and it will generate no power.  From the stators point of view a perfect closed circuit and an open circuit are exactly the same thing.  You only get power when there is resistance.

The closed circuit, or shunting method is the way our stock R/R works, using a thyristor (SCR).  Trouble is the thyristor will drop voltage a couple of volts through internal resistance.  This you will see as heat in the regulator - around 50 or 60 Watts so quite hot.  SCRs fail when they get over hot.  The advice to put these devices in the wind stream is sound.  If they fail switched to ground then that is not an issue (except your battery will go flat), but otherwise you will get a boiling battery and blown bulbs and TCIs from over voltage.  Mosfets are an advance on SCRs but were still high-end technology in 1982.  They have about 1/3 of the voltage drop of an SCR, and so much less heat.  Mosfets and SCRs are low current devices and shunting also only works up to around 500 watts / 35 Amps. 

The open circuit method uses a series or in-line switching regulator that opens or closes the circuit as needed.  The big issue with these is that they are a lot more complex  to build circuitry because opening and closing AC circuits cause a lot of EMF noise, high voltage transients.  Series regulators will handle much bigger loads than shunts, but they are typically more expensive (though less of an issue these days). There is an alternate type of series regulator that does not switch, but acts as a big variable resistor discarding all unwanted power as heat.

Why do we get stator melt-downs if they are only working on-demand? Three main reasons that I'm aware of... 


1) The circuit when regulating is not a perfect closed circuit - you have wiring, connectors and a R/R in that loop, and you can get high resistance conditions in any of them.  The most likely is the connector, and stator failures are usually associated with a burned out connector.  As resistance in the dirty/corroded connector gets higher, stator output climbs, either the connector self destructs or the stator does.  This is easily detected by measuring voltage before and after the connector.  Pull it apart and clean it.


2) SCR regulators use a brown sense wire.  The ignition switch gets dirty and causes a voltage drop so the R/R goes full blast all the time even on a well charged battery causing a high voltage boilover and/or a melted stator and/or fried TCI or blown bulbs.  Mosfet regulators don't suffer from this.  This is easily detected by measuring voltage between red and brown wires - it should be near to zero, but I have measures several volts on a shitty ignition switch.  Pull it apart and clean it.


3) Defective/undercharged batteries will cause high amps to be drawn for longer than the stator can tolerate.  This is easily detected by measuring battery voltage or current draw.  Charge your battery before going riding, and monitor bike voltages.


WWJD?
Mosfet regulators are known to be reliable effective and electrically quiet , and since we now know that the full tits theory of stators is a myth, would be happy enough with one of those as long as I wasn't planning to get a high output stator to power my heated vest and gloves.
Now that series regulators are cheaper I'd be inclined to give one a go except that I have several microprocessors to worry about - I'd be worried that the additional noise would cause issues.



George R. Young

Quote from: ProphetOfDoom on September 12, 2015, 08:39:09 AM
. . . . The full tits theory is a common misconception.  Truth is you can put the stator into a dead short and it will generate no power.  From the stators point of view a perfect closed circuit and an open circuit are exactly the same thing.  You only get power when there is resistance. . . .

Beg to differ about this. There is a DC resistance spec for the stator windings, about 1/2 ohm. At a few thousand RPM with the stator windings shorted, there's about 20 Amps flowing and the power generated in the stator is I**2R = 20**2 * 1/2 = 200 Watts. Even with the stator not shorted but feeding the rectifier/regulator/battery/bike load, the current is approximately the same (because the AC voltage is quite a bit higher than 12v) and the internal stator heating is approximately the same.

My own experience with 3 stators on the Vision is they overheat, the insulation becomes carbonized and eventually breaks down, shorting the windings to ground.

Ken Williams

The stator is constructed of wires wound around a metal core.  It reacts to the stimuli presented to it, chiefly magnetic flux and resistance/impedance connected to the output wires.  With the engine spinning, the changing magnetic flux causes AC voltages to be generated between phase leads.  When a non-infinite resistance/impedance exists between phases, current will flow. 

With the engine not spinning, no power is generated because magnetic flux is not changing.  The charging current available increases as a function of RPM until it levels out at about 4000 RPM.  For the shunt regulator, assuming "full blast" means maximum current, full blast current occurs only at 4000 and above RPM.  At idle only mini-full blast current is available. 

With the stator in an open circuit condition, no power is generated in the windings.  The only internal heating is from eddy currents in the core.  When current is flowing through the windings, additional power is dissipated in the windings due to their resistance as George indicates.  This occurs with the stator in normal operation and with the stator leads shorted (zero resistance).  It is true that no useful power is generated when the leads are shorted.  It's all being dissipated in the stator resistance. 

Series regulators are likely to cause more electrical noise.  This could cause issues with microprocessor based electronics; especially those not designed to OPM noise immunity standards.  I assume series regulators and modern electronics on modern production motorcycles typically function properly since I am unaware of evidence to the contrary.

vl5150

I got the Regulator/Rectifier in and I'm doing the install now.  I'm detailing it an a new thread.