question about RR failure..

I dont like bananas

 

Bananas are a good source of Potassium. Perhaps a banana thread is in order?

 

I still don't like them.

 

Would you object to eating one of these?

 

I'm so hungry I could eat a waitress... :biggrin:

Anybody know of an easy way to convert an AutoCAD file to an uploadable image file of some kind? Most of my software is older, circa 2000 or so. I have the normal Office apps, but all of my attempts to copy/paste/export etc. end up being either low resolution (bitmap) or huge (eps). I've finished the schematics well enough to show the operational differences, and would like to finish the task before I forget about it. :smile:

 

try to save it as a pdf, if not- print it out and scan it back into your computer.

 

First off, my experience with “electronics” (versus “electrical”) has been limited to a practical understanding of the various components typically used. My reason for mentioning this is that my description of what the components are doing may not be entirely accurate. If any members with knowledge greater than mine care to correct anything, I welcome the education. Please be nice, as my feelings are easily hurt. :smile:

The schematics shown are pretty basic, and are intended just as a way of comparing the differences between the two styles of R/Rs. The “CONTR.” insides are unknown to me, but I expect there are various transistors, diodes and resistors. For the purposes of these descriptions, the only thing that matters is that they sense a predetermined voltage and react accordingly. I’ll refer to the predetermined voltage as the threshold voltage, for lack of a better term.



RR_Schematic_A - VFRworld Photo Gallery

The first schematic is an SCR R/R in the battery charging mode. The SCRs are not turned on, as the operating voltage is below the threshold version. In this mode, the diodes are rectifying the AC output of the stator into DC voltage, which is charging the battery and operating the miscellaneous loads. The small arrows are meant to determine current flow.



RR_Schematic_B - VFRworld Photo Gallery

In this schematic, the threshold voltage has been exceeded, and the controller has turned on the SCRs. The positive half of the AC waves is now flowing through the SCRs, then through the negative rectifying diodes, and back through the stator. Note: this is one of those areas that confuses me a bit; does the current actually make it back through the diodes, or just get shunted to “ground”, such as it is? In any event, the stator is still in full output mode, and at least some portion of the excess power is dissipated as heat in the R/R.



RR_Schematic_C - VFRworld Photo Gallery

This is a typical MOSFET R/R. Note that there are no negative rectification diodes: they have been replaced by the MOSFETs. The MOSFETS used are known as “N Channel Depletion Mode” types, which essentially means that they act like a diode unless a control voltage is applied to the gate (the line that runs from each MOSFET to the controller). Varying the voltage on the gate will regulate (or stop) current flow through the device.

When the threshold voltage is low, the MOSFETs are acting like diodes, and current flows to the battery and loads. When the threshold voltage is exceeded, the controller either turns off the MOSFETs or reduces current flow through them; I have no idea how tightly they are controlled. In any event, the excess power being generated by the stator is not being dissipated as heat in the R/R body as it is in the SCR R/R.

I don’t know much at all about what happens to the excess energy in this case. Again, my acquired knowledge on many subjects tends to be limited to the practical stuff one uses when troubleshooting and repairing. Anyway, if the MOSFETs are partially conductive, I guess they might look like a high impedance diode and some of the energy would be dissipated as heat through the voltage drop across the MOSFET junction. If they are turned off completely, then the stator leg(s) would essentially be an open circuit, and the AC waves would have nowhere to go. How that affects the stator output is unknown to me, other than I’m not aware of it being an issue.

So that’s that, and about all that I know on the subject.

PS Thanks, tinkerin and O2. I need to figure out how to make the images bigger, which is what I'm off to do...

Edit: Thought I figured out the image resizing; I was wromg

 

A lot of misconceptions about "RR's"

As far as "running hot" That is what a RR does. It gives off excess voltage or energy as heat. That is WHY is basically a large aluminum heat sink with fins. The fins increase the total surface area.

A RR has diodes in it back to back so that current can only flow one way.
The electronic symbol is literally two arrows facing each other.

I t is supposed to regulate the power to give enough power back to the battery but not so much that it cooks the battery.

I am not an electronics expert and I am sure a electronics engineer can give you a more perfect and exact explanation.

If you motorcycle has a charging problem it is not wise to determine
that since the RR is hot it must be bad. You need to look at the whole charging circuit. Is the battery getting hot(overcharging) or is the battery not getting charged enough due to a fault with the alternator or the RR and do not forget the connecting wiring. If a battery has a poor ground ( loose, or covered with black greasy electrolites), then that needs t be addressed.

It is VERY common in the winter for the horn and lights to work but it will not turn over. That is almost always a dirty battery terminal.

And if the ground is bad , or becomes disconnected, that can instantly ruin the alternator.

Remember the RR is supposed to get hot . That is its job. Give off excess voltage as heat.

 

I have no disagreements, Donald, even though the common motorcycle charging system is kind of inefficient and primitive. Most of the time, they work just fine.

But heat is the big killer of electronic components. A cooler R/R will last longer, everything else being equal.

And Crusty, I see that I managed to avoid offering my perspective/opinion on your original question regarding batteries and charging system reliability. I would think that it ultimately wouldn't matter a lot IF the bike has a permanent magnet alternator (which is what we've been discussing). Some older bikes have automotive-type alternators and R/Rs that would see more of a heat burden from having to be in a full output mode for a longer period of time if the battery was in a low state of charge. Since the permanent magnet type are always in full output mode, I'm guessing that an electrical load is an electrical load, period; the charging system doesn't really know the difference between a low voltage battery or heated apparel.

I'll relinquish the soapbox now. :biggrin:

 

Recall? RECALL! Are you talkin to me?

All those flakey R/Rs didn't have fins.. They got so hot the potting got cheesy. Just a matter of piss poor engineering and Honda saving face by looking the other way.

 

Everything I have experienced with RR failure indicates that heat is the big killer. Causes can be insufficient air flow to dissipate the heat, bad electrical connections such as poor grounding and poor plug connections. Of course, sometimes it is just a bad RR. Relocating the RR to a place where it will receive better airflow will help. Another method is to use ducting hose to provide airflow over the RR. Keeping the electrical connections clean and free from corrosion is also a good thing. Another method is to mount a heat sink onto the RR. My experience with dirt bikes has convinced me that regular cleaning of the grounding connections and cleaning and applying dielectric grease to all the electrical plugs is a good thing.

 

I have some air tubes from a triumph speed four, that I wa thinking about fashioning into vent/dair flow to direct air directly on the RR. just not sure how yet......maybe the computer fan might be better.

 

Frequently, problems blamed on the R/R ( or stator) are really caused by dirty/corroded/burned/melted plug connector terminals, usually at the 3-wire plug between stator and R/R or at the main plug on top of starter relay.

I'm pretty sure that if the melted 3-wire plug causes a short between the wires, it kills the stator. Hard to believe, but the melted plug below was still flowing juice, and i'm lucky i caught it in time.

Ancient wisdsom suggests that Honda improperly routed too many components --including the R/R--to ground through the same small wiring harness leads and that grabbing a green wire connection right at the R/R leads and connecting that wire directly to the negative battery post might prevent many regulator failures.

 

If those Triumph air tubes are 12v they should work fine.