What color are the wires and connector coming from the alternator.That is the code that tells you the output ,in the B/S manual.tbk

The battery IMO has nothing to do with it unless it's dieing and pulling higher than normal charge. Once the engine is running it should charge and power some lights. Most charging systems once you get the engine started you don'tneed a battery.

If you add the light and the rest go deem, then you've added too much. If the orginal lights are inadequate then remove the bulbs and go with the add on lights to reduce a possible overload. You can hook up a multimeter and monitor the amps or volts when you have everything lite up.

But, adding more power may weaken the old system enough to cause it to fail. So, if may work for a while then you will be in the dark and not moving.

You can greatly reduce the load imposed by the additional lights by using LED lights instead of incandescent. LEDs use about 1/10 of the wattage of a regular bulb. They are expensive, but probably cheaper (and easier) than upgrading the alternator.
The battery does play a role in allowing you to overtax the charging system. If you're drawing too much current, the battery will start to drain. In my case, I installed off-road lights on the bumper of my JD GT225 to give me some low-angle illumination for mowing at dusk. when I have both the (mostly adequate) stock headlights and the off-road lights on, it drains the battery to the point where the low charge light comes on. Then I turn off one set and let the battery charge back up. That works for temporary conditions (like if you wired a switch to your rear light to only make it work when you're backing up). But I think the better solution is to go with LEDs.

that 18HP briggs is out of what tractor?

Bulbs are usually rated in watts (if you use LEDS use the actual wattage NOT the "watts equivalent").

Volts x Amps = watts.

Therefore Watts/volts = amps

Since this is almost certainly a 12 volts system: watts/12 = amps.

You will need to look up the specs on your engine.

If you will be running continuously for hours at a time, then you want to use no more than you charging system puts out minus a recharge amount for starting.

If you have a 20 amp alternator then you can support about 15 amps worth of accessories.

In that case, 12 volts x 15 amps = 180 watts for all accessories.

If you have different size alternator then allow for 5 amps for recharging and for the ignition system. Take the remainder and convert to watts, see below.

You guys are making this much too complicated. Add what lights you desire and if the charging system cannot supply what current you need the battery will make up the difference. That is, the battery possibly will have a lower charge on it than when you start out. But so what, let the engine run, at about half throttle AFTER you finish and turn off the lights to full recharge the battery. However, you may need a higher capacity battery eventually. Works for me.

It is unlikely you have any lights running on AC.

Yes, like canguy said, the oem lights only work with the engine running, and they're really annoying that they always dim at lower rpms...especially when I don't plan to be plowing at full throttle just to get some light. The light I wired in the rear is an entirely seperate ciruit running from the battery with it's own switch. I had it on with the engine off for a few minutes, and started the tractor right up,and the light barely flickered when the engine cranked. I also see no difference in the front lights, when I turn the other one on and off, and the other way around as well.

As far as wire colors, the only color other than red and black I see, is an orange wire...I've found the IPL on this engine, but have only been able to determine that it's a dual circuit system, but I don't know the amperages, and the owners manual pdf that I found on it says nothing either.

Here is a link that might be useful: {{gwi:358759}}

I suspect your rear light is already using more juice than your Briggs puts out - A quick and simple way to test is to measure the voltage at the battery

Run the engine at your normal RPM's and measure the battery voltage with your light off. Hopefully, you'll have 13 or 14 volts

Next, turn on your rear light and measure the battery again. If the voltage stays about the same, then your light is being powered by your engine's alternator - If the voltage drops below 12.5, you don't have enough alternator power and you're running your battery down. Adding more lights to the front will only run it down sooner

Running off the battery and then allowing the engine to run a few minutes to recharge the battery is no viable answer - The 3 or 4 amps your engine puts out could take many hours to recharge your battery after you run it down with your added lights

Don

According to my chart, the Dual circuit alternator puts out-
14 Volts AC (Min.)
2-4 A, DC Unregulated

From that, I'd assume your tractor doesn't have an electric PTO? That would be an indicator that you have a low capacity alternator, since they take something like 4-5 A.

Red & Black wire with a White connector. Raised rib on connector is the DC side.

Put whatever lights you want on the front and back. If you limit all your added lights to about 70 watts, that will be about 6 amps. Connect your added lights across your battery, with a switch and a 10 amp fuse in series with the hot lead. If you have more lights than you charging system will support, you will be discharging your battery a little when they are on, but so what? Turn off your lights and let the tractor charging system charge the battery back up when you are through. Or charge it back up with an external battery charger. I suspect your charging system is 20 amps, mine is.

I just bought my first ever riding lawn mower (CC 1050) so I'm no expert on these but they do have a lot in common with motorcycles. Both use a stator/rectifer-regulator setup. The stator simply puts out wide open for what ever speed the flywheel is spinning and the rectifer changes that a.c. to d.c. The regulator insures a charging voltage roughly 2 volts more than the battery. Any excess is usually shunted to ground. So, you have around 14 volts across the battery when the engine is at speed.

People think the electrical accessories are connected to the charging system but they are actually connected to the battery. If you connect more "stuff" to your battery than the charging system can support the battery will not stay fully charged. A lead-acid battery needs to be fully charged all the time. Left discharged it will become sulfated which means it will not take a charge.

A poster above stated correctly that after connecting your extra lights make sure you still see about 14 volts across the battery when the engine is running and you'll be fine. When not knowing the actual load or output this is an easy way to tell. If not, don't use the extra lights unless you want battery trouble. Of course you could keep a battery maintainer on your battery when not in use and that's not a bad idea.

We have these conversations all the time on the motorcycle forums. Bikers like to add accessories too.

Ray

"People think the electrical accessories are connected to the charging system but they are actually connected to the battery."
Since the charging system is connected to the battery, how can the accessories only be hooked to one?

The battery is the source for electrical power. The charging system charges the battery. A few extra light bulbs won't damage the charging system. They may take more from your battery than your charging system is capable of restoring though resulting in a discharged battery. Sure, they are both connected to the battery but one charges, the other discharges. It's just a way of looking at it. Maybe it's like money going in and out of a bank account. Sometimes I think I have too many light bulbs on. :)

The point is excess load won't hurt this simple kind of charging system. The charging system on my mower and my bike operate at maximum output all the time anyway. The limiting factor is engine speed. Any excess not needed to charge the battery is sent to ground by the voltage regulator.

If you actually looked at a lawn tractor schematic, you'd see that in most cases, any accessories are tapped off the 12V feed from the regulator to the ignition switch!
Any excess current goes through the ignition switch and recharges the battery. IF insufficient current is available from the regulator/alternator, the battery feeds the opposite direction through the switch.
The battery is the source for electrical power? Why would you need the alternator then? The battery is simply a storage device! The sun is the source of electrical power!

Oh, you're right! I was just speaking of the small area under the hood of my mower. Thanks for clearing that up!

Ray

"Any excess not needed to charge the battery is sent to ground by the voltage regulator."

This is not quite correct. The voltage regulator is designed to do what it says. Let us review it's function: A 12 volt lead acid battery is really 12.6 volts and it takes about 14.7 volts (at some specific temperature)to charge it fully up. This voltage varies greatly with the condition of the battery and the temperature. If the voltage regulator is putting out too much voltage, say 15 volts, then it will overcharge the battery and over time cause some of the water in the battery to evaporate, because it continues to push current into the battery when it is already fully charged, thus heating the battery.

What really happens is the voltage regulator designer design it so that it only puts out about 14 volts and the battery is charged to about 90% to 95% of full charge and is never overcharged. This is true on bulldozers, LT & GT, autos, trucks, and $200,000 motor homes. (If it is 24 volts, double the voltages mentioned above.) And I don't know a damn thing about motorcycles.

A very simple battery hydrometer (available from Wall-Mart for $0.97) is much more accurate and easier to use than most of the volt meters we have. If your battery is being charged to somewhere between 75% and 100%, that is all you need to know. And that can be determined by how many little balls are floating, which never need to be calibrated or tested, as ANY voltmeter does. If you don't believe this take a federal government contract for electronic equipment and see if they don't make you set up a testing lab to testing and certifying YOUR voltmeters and other equipment traceable to the Bureau of Standards before you ship to them.

Surely is about time for our friend Wally2q to wade into this discussion.

This is a no win discussion - but here goes.
P = I x E or I = P/E
If you overload the charge circuit the fuse blows in this circuit from to much current(I) required, since the voltage(E) output is constant at(12.6V to 14V) this fuse is protecting the alternator and voltage requlator, most small engines today have the diodes in the VR rather than in the Alternator. If the fuse don't blow first the diodes will be the next thing to blow(blow = burn out from excessive current(I) flow).
If you really want to see how this works add a large wattage(P) rated bulb to your tractor - same voltage(E) 12V in most currently manufactured LT/GT, since Voltage(E) will remain constant (approx 12V) the Current(I) draw will increase - exceeding the fuse rating and "poof", put in a larger fuse and exceed the current rating of the diodes next and "poof".
As far as to what happens to the current(I) when the battery reaches a fully charged state Voltage(E) 12.6V the circuit opens(switch turns off) stopping current(I) flow.
The method of "turning this switch off" is another discussion, but a short course in basic electronics will help your understanding.
If someone knows of a regulator circuit of where "excess current(I) is sent to ground", please share the electrical schematic with the components required to do this and the equipment of where its found.
If you all haven't figured it out by now. You can overload a charging circuit and guess what two bad things will happen.
One last comment, when starting a engine there is no current(I) output from the Alternator therefore all starting current comes from the battery and not the charge circuit so thats why a large current(I) flow doesn't effect the fuse or diodes in the case.

This might need some further clarification (or maybe more mud in the water). There are references being made in these posts to two DIFFERENT kinds of "alternators".
The "voltage regulation" or "voltage limitation" technique (and components)differs greatly between the 2 types. Both types utilize DIODES to "rectify" the AC output (which the battery has no use for) of the stator into DC (which the battery can use). There is the "automotive type" where the alternator is a separate component, mounted to the engine and provided with an external drive system. In this type of alternator, the "field magnetism" is provided by small gauge (relative size) wiring coils that comprize the "rotor". When the rotor spins, the electromagetic "field" spins along with it. As the rotating "lines of flux" pass through the large gauge wire coils of the "stator" (output of alternator), CURRENT is INDUCED into the stator windings and passes out of the alternator and into the COMMON BUSS conductors (which are in continuity with both the battery and any electrical load that is "ON" at the moment. The system voltage level in this type of alternator is controlled by using a VOLTAGE REGULATOR to VARY or ADJUST the electrical current being "fed" to the rotor windings. The output of this system can be relatively constant (within a range of RPM) due to the strength of the electromagnetic rotating field being the determining factor of alternator output. If the voltage regulator detects a "system voltage level" lower than normal "lower limit of electrical system"(it's default setting), it will send more current to the rotor windings.....resulting in a greater strength electromagnetic field, which in turn INDUCES a greater CURRENT into the stator windings and the electrical system. The increase in field voltage and strength can reach the point where the theoretical maximum output of the alternator might be reached (it's trying to recharge a battery AND keep up with other loading). At the point where the SYSTEM VOLTAGE level increases to MORE than the "upper limit of the electrical system" (battery is nearing full charge or other electrical load is OFF), the regulator will send less current to the rotor windings and in turn the alternator output will be reduced. Now we go to the type of alternator most often found on modern day, small, OPE. In this type of alternator, the "field magetism" is provided by "permanent magnets" located in the "rotor". The "rotor" in most cases is THE FLYWHEEL. The same magnets induce current into the alternator windings AND the "ignition magneto" windings, (if magneto ignition instead of battery & coil). The output volume of this type is not constant. It is infinitely variable (for the scope of this discussion only). In this set-up, the only determining factor of MAXIMUM alternator output is the RPM of the engine. In essence, this alternator is always producing the maximum current possible, dependent on the RPM at any given moment. After this output current is "rectified" (by diodes in the rectifier), it passes INTO the VOLTAGE REGULATOR (or "limiter"). This device measures the "system voltage level" and will pass all or most of the available output from the alternator into the electrical BUSS of the machine, if, the system voltage is below the lower limit of regulator. The regulator will continue to "feed" the electrical system so long as the system "needs" the current (to charge battery and/or satisfy the component load). When the battery nears full charge, or the electrical load from accessory components is turned OFF, the regulator senses the increase in system voltage and will at this point start "shunting" the excess output current (from alternator) directly to "ground", thereby preventing the system voltage from rising to an unacceptable, high level, causing harm to the battery.
Some engines in OPE have a separate (but using the same magnets in the rotor as above) and additional "alternator output" to power headlights (or simply "lights"). The output of this winding IS NOT RECTIFIED or REGULATED, it is pure AC. It simply has a preset (by design) maximum output that can only be attained by running the engine at maximum RPM. This is why the lights on so configured machines "dim out" at low RPM and brighten as RPM is increased. This output winding has NO BEARING on charging the battery or operating any components that run off the main battery/charging system.

A dual circuit alternator puts out 2-4 amps DC+ for charging, and 5 amps AC unregulated for lights. This is from the Briggs Twin repair manual. With only 4 amps of charging current available I'd be careful how much lights you use off of that battery. I think I'd supplement the charging circuit with a small trickle charger which I would hook up after using the lights and let it charge overnight and then pull it off the next day. If you have, or can get, a float charger or battery maintainer then you could leave it plugged in all of the time.

Mr. Mownie:

Would you be so kind as to tell us where we can find a schematic, diagram, additional information, or shop manual on reasonable modern equipment where we may review what you describe below. That is assuming this equipment has a battery in it and is electric starting.

"Some engines in OPE have a separate (but using the same magnets in the rotor as above) and additional "alternator output" to power headlights (or simply "lights"). The output of this winding IS NOT RECTIFIED or REGULATED, it is pure AC. It simply has a preset (by design) maximum output that can only be attained by running the engine at maximum RPM. This is why the lights on so configured machines "dim out" at low RPM and brighten as RPM is increased. This output winding has NO BEARING on charging the battery or operating any components that run off the main battery/charging system."

I have a copy of Briggs "L-Head Twin Cylinder Repair Manual". In it it describes several different Alternator/Stator configurations, including 5 amp unregulated AC, 3amp unregulated DC, Dual Circuit 5 amp unregulated AC with 3 amp unregulated DC, which the original poster has, and 5, 9, 10, 13 & 16 amp regulated outputs. The outputs are determined by the size of the magnets in the flywheel. The following is a direct quote from the book under the description of the dual circuit alternator.
"The Dual circuit alternator provides DC current for battery charging and an independent AC circuit for headlights. The battery is not used for lights so lights are available even if the battery is disconnectd or removed.

Current for lights is available as long as the engine is running. The output depends upon the engine speed, so the brightness of the lights changes with engine speed. 12 volt lights with a total rating of 60 to 100 watts may be used. With lights rated at 70 watts, the voltage rises from 8 volts at 2400 RPM to 14 volts at 3600 RPM.

Current from the DC side of the alternator is unregulated and is rated at 3 amps. The output rises from 2 amps at 2400 RPM to 3 amps at 3600 RPM."

OK, this will take some time to wade and weed through all the examples, but for a starting point (is that a pun?) click the link and READ carefully (paying attention to all illustrations and the captions that go with them). Though this is a MOTORCYCLE website (the link) the info is applicable to other types of engines as well. I will post other links as I discover them.

Here is a link that might be useful: Permanent magnet vs. excitable field

Well this shows that I have not seen everything, I have been suspecting that for sometime. Thanks for the education.

Bill

Found this article regarding "hobby aircraft". I seem to find more articles about permanent magnet alternators in motorcycle and aircraft venues than elsewhere. Maybe there is simply a larger group of curious mechanics/tinkerers in those fields (is this another pun?) than in lawn and garden circles???? or perhaps I'm not peering under the right stones.

Here is a link that might be useful: Another mention of shunt to ground for voltage regulation

Mownie,

As usual, your forceful lines of explanation are current!

Puns intended!

Uhhhhhhhh....thanks, WHOC. (I think) May the EMF be with you.

Cut to the chase.

You can probably use the light you are talking about. If there is any doubt about your charging system put a trickle charger on your battery--or a battery maintainer--after you have finished. Unless you are spending hours in the darkness on your tractor you should be okay.

The knowledge displayed on this forum is impressive to say the least.

My battery was dragging tonight and is hooked up to a trickle charger--it might get down to 32 tonight. ;-)

We are LOVING our new house!

The battery is only needed for the starting system,for the starter to start the engine.After that,it is not needed.Everything else is powered by the seperate and independent charging system.If the load ie ( extra lights) applied to the alternator/generator is above its output,than current will be drawn from the battery.Eventually the battery will become completely discharged and the generating system will burn it self up.It is as simple as that.Red and black wire with a white colored connector. is 2-4 amps+ DC charging, and 5 amps AC (lights) unregulated. sorry.....tbk

Charging systems are designed to endure continuous output at 100% duty cycle. In fact, where the alternator uses PERMANENT MAGNETS in the rotor, the alternator IS ALWAYS producing MAXIMUM RATED OUTPUT (for the RPM at any given time). On these types of systems, you can only divert the excess current to ground when it is higher than the requirements of the electrical load of the machine at that moment. On systems that use an "excited field" alternator, running at continuous 100% duty cycle will result in a shorter life span of the brushes (due to the higher field current) but will not cause "burn out" or "burn up" to any wiring in the alternator. If you "up-size" a replacement alternator to something with a greater Amp output without also increasing the capacity of the wire that connects the alternator output post to the main buss of the vehicle, you could melt that wire if the bigger alternator runs at MAX OUT for a while.

It appears to me that many of you are thinking of older charging systems not used on any engines produced in the last 10 or so years for GT or LTs. Some may have diodes arranged in a bridge for full wave rectification and the output is fed into a voltage regulation circuit there the voltage is constant at about 14.5 volts all the way from no load to full load, thus no need to shunt any current to ground. The output of the regulator is effectively connected across the battery and stays that way. Too much current being supplied is protected by the regulator circuit or by a fuse is series with the output of the regulator.

Sure too much load will burn out or disrupt the rectifier/regulator, as in blowing a fuse, but not if it is connected to a descent battery. The battery will supply the needed current until it discharges to the point you notice the lights are getting dim. The battery is the cushioning/protection devise, along with current limiters in the charging/regulator and fuse.

A single light isn't drawing too much, correct? Mount it so that it can swivel fore and aft.

Well, I've been busy blowing snow and even made a few turns at the local ski hill.
But, I see mowie as well as others have come up with schematic's and parts list where the output of the alternator is grounded when excess is generated. As I said in my previous it would be a no win discussion, I got that part right at least if you include all small engine applications.

Dare I inject this further nugget? When I was a kid I rode a Cushman Eagle motor scooter (magneto ignition, no battery, kick starter). It had a second coil under the flywheel that generated an unregulated a.c. voltage for the headlight and tail light. I remember the Department of Public Safety officer cupping his hands over the headlight to see the feeble light at idle before he gave me the driving part of the driver's lisence test.

Ray

The fuse in the charging circuit of a permanent magnet system is not there to protect the regulator or the rectifier. By design and specification, the rectifier and regulator can be subjected to maximum output continuously without suffering. In fact, the rectifier & regulator on these systems is always operating at maximum output. Whether it all goes to the battery and electrics of the machine, or whether it is bled off to ground at the regulator has NO EFFECT on alternator output. That is why I mentioned early on that the so called "regulator" in this type of system should really be called a "limiter". It would be more realistic to call this device a "charging current limiter" but habits and tradition are hard to break. In an automotive, "excited field" alternator system, there truly is some "regulation" taking place that has a direct effect on how much output is produced by the alternator. That "regulation" involves modulation of the field current to affect control of the alternator output current. With a "permanent magnet" system, there is no controlling of the field current. It is whatever the field strength can be, according to how powerful the magnets are. So, the only variable in output on this type is engine RPM. The alternator is ALWAYS producing the maximum output for the RPM at any given moment. At low speeds and a weakened battery, 100% of the output might be directed to the main buss & battery. As engine RPM increases, there will be reached a speed where the needs of the battery (and other loads) are satisfied. From this point on, the output of the alternator is diverted into the common ground circuit of the machine by the regulator (uh...limiter).

Bull mownie! In a modern regulation system as used on LTs and GTs, there is no current passed to ground. The output voltage is held constant at whatever the designer desired, all the way from no current output to full current output, without leaking current to ground or neutral. (Of course a small amount of current is consumed in the operation of the regulator system, but this is not done to get rid of excess current.) This is done in much the same way that the power supply in your computer supplies a steady voltage under varying loads. It is done with zener diodes, and other solid state devices.

If you put a resistor in series with a zener diode and flow a DC current through it, and keep the current within the operation range of the vener diode, you can vary the input voltage over some range and the voltage across the vener diode will stay very constant. The voltage across the resistor will vary but not across the vener diode. Taking your output across the vener diode will give you a regulated output. Spend some time with voltage regulator circuits.

Constant voltage can be obtained from whirling flywheel magnet systems by feeding that output into rectefiers to convert its output into one direction flowing current, instead of backing and forth flowing current (AC) and then feeding that one direction flowing current (DC) into a regulator circuit to get a constant voltage over a varying load. That is the reason we call them regulators. Meaning the output voltage is relatively constant all the way from no load current to full designed load current.

All my restored collection of older LTs and GTs, dating back to 1989 have regulators on them for the charging system.

The "F" wire is to the generator field windings,in the "vibrating" points type of regulator.Battery voltage and/or load determins the field coil strength of the regulator field contacts in the regulator.The points vibrate faster,or slower,causing the gen magnetic field windings to be stronger,or weaker,and this determines the output of a strarter/generator.Never to ground.To get a flatout charging rate,ground the "F" wire,and the generator will charge more than you ever want it too,till it starts to smoke and sling solder.I have always adjusted MY OWN to just a tad under the max specified.Around 15-16 amps with a low battery,or more the normal load,ie extra lights.I Went to automotive school in the 40's and 50"s on these things,and not many changes in them..tbk

"Bull mownie! In a modern regulation system as used on LTs and GTs, there is no current passed to ground. The output voltage is held constant at whatever the designer desired, all the way from no current output to full current output, without leaking current to ground or neutral. (Of course a small amount of current is consumed in the operation of the regulator system, but this is not done to get rid of excess current.) This is done in much the same way that the power supply in your computer supplies a steady voltage under varying loads. It is done with zener diodes, and other solid state devices.

If you put a resistor in series with a zener diode and flow a DC current through it, and keep the current within the operation range of the vener diode, you can vary the input voltage over some range and the voltage across the vener diode will stay very constant. The voltage across the resistor will vary but not across the vener diode. Taking your output across the vener diode will give you a regulated output. Spend some time with voltage regulator circuits.
"

With all due respect, you do not understand how a zener diode works. You do not connect it "resistor in series with a zener diode and flow a DC current through it". A zener diode has a high impedance until the voltage gets to a certain level (zener breakdown voltage) and then abruptly turns to low impedance. The way you build a regulator with them is connecting it between the supply and ground, perhaps with a resistor in series with the source, depending on the impedance of the source. The diode clamps the voltage to the zener breakdown voltage of the diode. See the schematic in the "Uses" section of this Wikipedia page:

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

The lower node would be ground, the upper left is the unregulated voltage, and the upper right is the regulated voltage. So, if the regulator is using a zener diode, curent is indeed shunted to ground to keep the regulated output at roughly the diodes breakdown voltage. Somebody earlier asked for the schematic, well there it is.

It is possible to design regulators that are more efficient and do not shunt power to ground, but not with a zener diode. BTW, power supplies are nothing like this and use high-frequency switching regulators.

Thanks docholiday for chiming in with that. Now everybody sort of keep your heads up and watch out for the "avalanche" that is coming. This first link gives probably the best illustration of how a modern, Zener diode voltage regulator accomplishes the feat of maintaining a constant voltage output from an UNREGULATED DC power source (this would equate to the RECTIFIED alternator output.....RECTIFIED but NOT YET REGULATED). In the illustrations, the full range of conditions one would expect to find in an application using a permanent magnet alternator (OPE fits here) to provide current, a battery for cranking (OPE fits here) and an ELECTRONIC rectifier and regulator device (OPE fits here). Keep in mind that electricity (ElectroMotive Force or just EMF) flows from one polarity to the opposite polarity in order for ANY work to be accomplished. Whether the "work" is causing an incandescent lamp to "light up", an electric motor to spin, a solenoid to "pull in" or for a spark to "jump the gap" in a spark plug, you must have "electron flow". In the "solid state voltage regulators" used presently (and for a long time previously BTW), Zener diodes, in conjunction with strategically selected and arranged resistors, determine that ONLY the DESIGN VOLTAGE is allowed to leave the regulator assembly and enter the main buss conductor of the subject machine's electrical system. Because electrical flow must be maintained, any "excess unregulated current" remaining (after the Zener diode establishes "regulated output" into the main buss) will be diverted, or "shunted" into the ground conductor of the overall machine. You cannot simply "evaporate" the EMF into another space/time dimension. It must remain here and flow.

Here is a link that might be useful: Best example as requested

http://www.opamp-electronics.com/tutorials/zener_diodes_3_03_09.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/zenereg.html

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

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

http://science-ebooks.com/circuitdesign/voltage_regulators.htm

No mownie. "Because electrical flow must be maintained, any "excess unregulated current" remaining (after the Zener diode establishes "regulated output" into the main buss) will be diverted, or "shunted" into the ground conductor of the overall machine."

A flash light battery has EMF and none of its current is diverted when it is not under load.

Current-voltage characteristic of a Zener diode with a breakdown voltage of 17 volt. Notice the change of voltage scale between the forward biased (positive) direction and the reverse biased (negative) direction. A Zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the breakdown voltage known as "Zener knee voltage" or "Zener voltage". Named for Clarence Zener, discoverer of this electrical property.

A conventional solid-state diode will not let significant current flow if it is reverse-biased below its reverse breakdown voltage. When the reverse bias breakdown voltage is exceeded, a conventional diode is subject to high current flow due to avalanche breakdown. Unless this current is limited by external circuitry, the diode will be permanently damaged. In case of large forward bias (current flow in the direction of the arrow), the diode exhibits a voltage drop due to its junction built-in voltage and internal resistance. The amount of the voltage drop depends on the semiconductor material and the doping concentrations.

A Zener diode exhibits almost the same properties, except the device is specially designed so as to have a greatly reduced breakdown voltage, the so-called Zener voltage. A Zener diode contains a heavily doped p-n junction allowing electrons to tunnel from the valence band of the p-type material to the conduction band of the n-type material. In the atomic model, this tunneling corresponds to the ionization of covalent bonds. The Zener effect was discovered by physicist Clarence Melvin Zener. A reverse-biased Zener diode will exhibit a controlled breakdown and let the current flow to keep the voltage across the Zener diode at the Zener voltage. For example, a diode with a Zener breakdown voltage of 3.2 V will exhibit a voltage drop of 3.2 V if reverse bias voltage applied across it is more than its Zener voltage. However, the current is not unlimited, so the Zener diode is typically used to generate a reference voltage for an amplifier stage, or as a voltage stabilizer for low-current applications.

The breakdown voltage can be controlled quite accurately in the doping process. Tolerances to within 0.05% are available though the most widely used tolerances are 5% and 10%.

Another mechanism that produces a similar effect is the avalanche effect as in the avalanche diode. The two types of diode are in fact constructed the same way and both effects are present in diodes of this type. In silicon diodes up to about 5.6 volts, the zener effect is the predominant effect and shows a marked negative temperature coefficient. Above 5.6 volts, the avalanche effect becomes predominant and exhibits a positive temperature coefficient.

In a 5.6 V diode, the two effects occur together and their temperature coefficients neatly cancel each other out, thus the 5.6 V diode is the component of choice in temperature critical applications.

Modern manufacturing techniques have produced devices with voltages lower than 5.6 V with negligible temperature coefficients, but as higher voltage devices are encountered, the temperature coefficient rises dramatically. A 75 V diode has 10 times the coefficient of a 12 V diode.

All such diodes, regardless of breakdown voltage, are usually marketed under the umbrella term of 'zener diode'.

I conclude: you leak off all your excess current you want. I think I will keep mine.

A flashlinght battery or any other "battery" has no EMF until it IS connected to a load. Until it is connected, it is just a container of chemicals. ONLY when a conductor path is established between the anode and the cathode of the "battery" will any EMF be realized. Yes, the characteristics of a Zener diode are like a common diode in that it will act like a regular diode and pass EMF in one direction readily while resisting the flow of EMF in the other direction UNTIL THE ZENER THRESHOLD VOLTAGE is attained. But........the first characteristic or property of a Zener diode IS NOT exploited when used in a typical DC regulator. Only the second characteristic (the Zener knee or threshold voltage) is employed (because there is no reason for EMF to be coming from the opposite direction in this application). The Zener diodes are placed in the circuit, biased so as to force the utilization of the Zener effect. The other characteristics of the Zener diode are simply an "unused, unneccessary property" in this application. I am willing to concede that everyone is right in clinging to their opinion. I will hold on to mine. Now let's all go play Santa. HO HO HO ! Merry Christmas to all.

bill_in_nc: You copied that right from the Wikipedia article, you should at least attribute it. But what you didn't copy was this:

"A zener diode used in this way is known as a shunt voltage regulator (shunt, in this context, meaning connected in parallel, and voltage regulator being a class of circuit that produces a stable voltage across any load)."

See the shunt part? That means enough current is dumped to ground to cause a voltage drop such that a more or less constant voltage is maintained across the zener.

Talking about a flashlight is nonsensical. We are talking about regulators here, not power sources. Flashlights, with the exception of a few high-end LED lights, do not have regulators and if they do, they are most certainly not shunt regulators because of the poor efficiency.

Bull again monie. My old college physics text: "Modern College Physics" by Harvey E. White, page 489 states: "This is why the potential difference between two battery terminals, which may be thought of as a kind of driving force behind the electrons, is some times called THE ELECTROMOTIVE FORCE (abbr. E.M.F.). Note: since there is no such thing as a perfect insulator, some current can be thought to flow, if you like.

And "docholiday", "with all due respect" you CAN HOOK A RESISTOR IN SERIES WITH A ZENER DIODE. That is the first circuit shown on the wikipedia.org/wiki/Zener_diode explaining how a zener works, under the heading of "USES."
I sold several thousand expanded scale voltmeters using this circuit. I chose a precision 10 volt Zener and a resistor to get the correct current flow correct through it. And measured the voltage drop across the resistor. The meter started reading only at 10 volts, and since I was interested only in 10 to 16 volts, I chose a resistor in series with a MAM to produce a reading of 16 full scale when 16 volts was present, thus a 10 to 16 volt meter. I have many in use now.

Gentlemen, I am tired of arguing, good by!

"A zener diode used in this way is known as a shunt voltage regulator (shunt, in this context, meaning connected in parallel, and voltage regulator being a class of circuit that produces a stable voltage across any load)."

See the shunt part? That means enough current is dumped to ground to cause a voltage drop such that a more or less constant voltage is maintained across the zener. quote>

You guys are both correct.

With a Zener diode some or all of the CURRENT is diverted to ground. This current is dissipated in a voltage dropping resistor.

Voltage drop (V) is directly proportional to the current (I) and the value of the resistor(R). V = I R. You cannot drop voltage without current flow.

So, the CURRENT is diverted (shunted) to ground. The resistor dissipates the POWER by creating a RESISTANCE.

I do own a Kohler manual with schematics of the voltage regulator. It certainly has more than simple a Zeener diode. I am away form howm so I cannot post that schematic now.

Have FUN!

"
And "docholiday", "with all due respect" you CAN HOOK A RESISTOR IN SERIES WITH A ZENER DIODE. That is the first circuit shown on the wikipedia.org/wiki/Zener_diode explaining how a zener works, under the heading of "USES."
I sold several thousand expanded scale voltmeters using this circuit. I chose a precision 10 volt Zener and a resistor to get the correct current flow correct through it. And measured the voltage drop across the resistor. The meter started reading only at 10 volts, and since I was interested only in 10 to 16 volts, I chose a resistor in series with a MAM to produce a reading of 16 full scale when 16 volts was present, thus a 10 to 16 volt meter. I have many in use now.
"

Bill, in an expanded scale voltmeter, you want to drop a fixed voltage, in your case 10V for the expanded scale meter. But in a regulator, you don't want to drop a fixed voltage, you want a fixed voltage on the output, hence you don't use a series zener, you instead put it in parallel with the load. Trying to compare an expanded scale meter circuit to a regulator makes no sense.

Sure you can put a zener and resistor in series with a voltage source to build something interesting, but it isn't sure as heck isn't a voltage regulator which I though was the whole point of this discussion.

I think all that feel, that grounding the output of the voltage requlator has no ill effects thier LT/GT should replace the fuse with a penny (or similar copper item) and then "ground the output of the VR using a 12awg copper wire" on "thier" LT/GT. Don't forget to post what the result is/was. We can settle this discussion using this method of "Voting"
I for one, think its not the best idea of the year and "will not be Voting" but I will accept your posting of the results on your GT/LT as the facts. As that good looking brunette sings in one her songs "I have better things to do".
Just think if damage occurs, Santa can bring you a sack full of new parts for your LT/GT.
Merry Christmas and a Happy New Year

What the heck are you talking about steve?

Most regulators I have seen have a ground connections. Whether current is diverted to ground (and how) during voltage "regulations" is the somewhat off-topic discussion that has been going on.

Interesting, but not interesting enough to read all the comments.

In autos (and many other items) the regulation is by changing the current in a spinning coil (hence varying the magnetic field).

In small engines, it is common to use a spinning fixed magnet to generate the chargeing energy. This has been common in motorcycles, snowmobiles, and lawn equipment. As this equipment has grown, more and more engines use the variable field as in autos.

As I remember, some just used the battery to waste the charge current and boil the battery dry. In fact this is still common in lawn tractors that use a 2 to 3 amp charge circuit and a totaly different AC circuit for lights.

I had a 1967 triump cycle that had a BIG Zener (around 14.5 volt) on the output of the charge circuit. This worked quite well as it dumped the excess power to ground.

I had the regulator on the kohler in my 1980 bolens die. I found it regulated by useing an SCR to 1/2 wave rectify the current from the alternator coil. It does have a 6 volt zener, only uses it for a reference to control the SCR turning on or not. It looks strange to me as the plus battery connection goes directly to the charge coil. The other lead of the charge coil goes to the scr which goes to ground.

Several older snowmobiles have used a light bulb balanced with a Zener to turn on a scr and crow-bar the AC to ground. BUT these have problems.
1) they only kill 1/2 of the wave (an open bulb and everything, includeing the regulater bulb burns out), AND
2) The reponse of the regulator bulb is so slow that a Quartz bulb will burn out before the regulator cuts in.
The solution to the regulator problem is to put back to back Zeners across the output (or 1 zener connected to a DC bridge).

The permenent magnet rotor has a characteristic that permits the shorting of the output without damage to commponents.
That is because the coils voltage out and the coils resistance (impedance, if you wish) are both proportional to RPM (ie. frequency). This gives the same current at modest RPM as it does at max RPM (when shorted). Or think of it as the current shorted being the SAME as under load.

JerryO

All I can say is "WOW".A wealth of great imfo,but got way over my head about 10-20 posts ago. Merry Christmas to all,and may your batteries always be fully charged . tbk