Two phase generator/Headlight switch WTF?

[Qdude]

I am rebuilding a bike for a friend

http://www.thegsresources.com/_forum/showthread.php?t=161190

And while I was re-wiring it I noticed that one of the wires coming from the generator ran through the headlight switch. It seems that turning off the headlight also disconnects one of the ac wires coming from the generator.

I am worried about this.

A. Is this done to lower the voltage created by the generator when the load is cut i.e. the front lamp is turned off? and if so

B. Am I going to run in to possible electrical overloads by hooking the generator wires directly to the rec/reg? (I am removing the headlight switch from the circuit and installing relays that will cut lamp power while the starter engages).

C. If that is the case, why is the regulator not capable of dealing with the voltage regulation?

I am curious about this system. Curious!!

 

[Steve]

That system actually works quite well. Since the voltage regulator is a shunt regulator, it has to momentarily short the output to ground to control the voltage. By turning off the headlight and removing that load, the stator is now putting out WAY more than is necessary to run the bike. Rather than shorting that much more of the output to ground, that second set of contacts in the headlight switch turns off only leg of the e-phase stator.

As long as you have your headlight ON most of the time (and it sounds like that's the way you are wiring it), it is recommended to run the three stator wires directly to the three rectifier input wires, bypassing that leg up to the headlight switch.

For those who are not installing a relay to kill the light while the starter button is being pushed (I did that, too ), it's OK if you leave the headlight OFF while starting the bike, but have it on by the time you start riding. This will prevent the regulator from working any harder than it has to.

By the way, for those who still have the stock wiring with the stator loop running through the headlight switch, don't think that you will charge the battery faster with the light OFF. I compared battery voltage on a 450 that still had the switch, it actually charged better with the light ON. Apparently, the third leg of the stator puts out just a little bit more than the headlight needs. :-\\\

.

 

[BassCliff]

Hi,

My bike doesn't even have a headlight switch, but the loop of wire is still there. My headlight is on all the time, no way to turn it off. I disconnected the useless loop of wire and have direct connections with all three legs of the stator to the r/r unit. There's more information on my webpage in the stator replacement guide, or is it in the r/r unit replacement guide? Pfffft! It's on there somewhere.


Thank you for your indulgence,

BassCliff

 

[Danjal]

Hi,

My bike doesnt' even have a headlight switch, but the loop of wire is still there. My headlight is on all the time, no way to turn it off. I disconnected the useless loop of wire and have direct connections with all three legs of the stator to the r/r unit. There more information on my webpage in the stator replacement guide, or is it in the r/r unit replacement guide? Pfffft! It's on there somewhere.


Thank you for your indulgence,

BassCliff

Same deal here. No headlight switch, but its still there. I just disabled that loop of wire too since I went over to one of duanages R/R units.

 

[posplayr]

That system actually works quite well. Since the voltage regulator is a shunt regulator, it has to momentarily short the output to ground to control the voltage. By turning off the headlight and removing that load, the stator is now putting out WAY more than is necessary to run the bike. Rather than shorting that much more of the output to ground, that second set of contacts in the headlight switch turns off only leg of the e-phase stator.

As long as you have your headlight ON most of the time (and it sounds like that's the way you are wiring it), it is recommended to run the three stator wires directly to the three rectifier input wires, bypassing that leg up to the headlight switch.

For those who are not installing a relay to kill the light while the starter button is being pushed (I did that, too ), it's OK if you leave the headlight OFF while starting the bike, but have it on by the time you start riding. This will prevent the regulator from working any harder than it has to.

By the way, for those who still have the stock wiring with the stator loop running through the headlight switch, don't think that you will charge the battery faster with the light OFF. I compared battery voltage on a 450 that still had the switch, it actually charged better with the light ON. Apparently, the third leg of the stator puts out just a little bit more than the headlight needs. :-\\\

.

Makes sense, assuming total power is 15A at 14.5V that is close to 200 watts. Dropping 1 of 3 legs is 66 watts, with the lights on 55 amps so there is at least an extra 10watts to charge the battery running on all three legs.

 

[posplayr]

C. If that is the case, why is the regulator not capable of dealing with the voltage regulation?

I am curious about this system. Curious!!

I just did alot of voltage measurements comparing SHUNT to SERIES regulation last weekend and has not thought about the question you pose till now.

As I responded to Steve, the 1 leg is worth (66 watts) about as much power as the headlamp (55 watts). The issue is not the R/R; it is capable of handling the extra current required for the headlamp. The only rationale then is that the stator can not handle the extra power it is required to dissipate when the lights are off. At the least there is enough concern about the extra power in the stator to actually go to this extreme measure of switching the stator off if he headlamp is off. This is due to the SHUNT R/R as a SERIES would not have the same effect.


differences discussed here.

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

 

[Steve]

... The issue is not the R/R; it is capable of handling the extra current required for the headlamp. The only rationale then is that the stator can not handle the extra power it is required to dissipate when the lights are off.

Shall I go back and edit to say "To reduce the load on the charging system, one leg of the stator is removed from the circuit"? :-\\\

.

 

[posplayr]

Shall I go back and edit to say "To reduce the load on the charging system, one leg of the stator is removed from the circuit"? :-\\\

.

I'm not sure that is any clearer. This concept of shorting the stator and the impact it has to heat is not clear to most. I'm not sure careful wordsmithing helps.

To be precise,

If the GS load is reduced, the SHUNT regulator will increases the stator current higher to divert the unnecessary power from the GS load. That puts extra stress on the stator.

Conversely, if the GS load increases, the SHUNT regulator will decrease the stator current to allow more of the power to be delivered to the GS load reducing stator stress.

Although this is precisely correct, without a schematic it doesn't make any sense.

It doesn't make sense that increased load causes reduced current and visa versa unless you understand SHUNT topology and how it differs from SERIES.

 

[Qdude]

mANY TH

Oooops

Many Thanks all, I now know what I need to do. Increase the load so that the SHUNT regulator will decrease the stator current. :clap:

I will hook up all three leads from the stator and disable the headlight switch so that it is default 'ON'.

Excellent help indeed, thanks again!

Q

 

[Steve]

... I will hook up all three leads from the stator and disable the headlight switch so that it is default 'ON'.
...

Feel free to connect the headlight cut-out relay as originally intended, that's a good idea. :clap:

I forget where I made the actual connection, but the yellow/green wire that is soldered to the top of the starter solenoid is the perfect place to connect your relay's trigger wire. Just use a relay that has an 87a terminal (normally closed). Connect the light to 87a and the source to 30. Wiring the relay in this manner is good because it is also "fail-safe". If the relay fails, your headlights are still ON.

.

 

[Qdude]

Thank you all, I now know what to do!
Take the headlight switch out of the system thereby increasing the load from the bike causing the shunt regulator to decrease the stator current allowing more power to divert to the load of the bike thereby relieving stress on the stator...

It occurred to me that cutting one of the legs of the stator would reduce the drag on the motor by one third... Particularly when load is reduced and the shunt regulator is increasing stator current diverting power from the load. I now see why the stator switch leg exists.