Panhead Wiring

Panhead Wiring

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awander
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Re: Panhead Wiring

#16

Post by awander »

RooDog wrote: Tue Jun 16, 2020 11:04 pm The GEN light comes on in the run position because the ARM is grounding the light, and goes off once the genny is putting out more voltage that what's in the battery. There is no current flowing with the switch OFF.
Solid state, or mechanical it goes through the A terminal on the genny. It's really quite simple....
....RooDog....
Well, maybe not quite that simple, Roo....

With an electro-mechanical regulator, the generator "A" terminal is isolated from the battery by an air gap, and so no battery current can possibly flow through the armature winding to ground.

With a solid-state regulator, there is no air gap, just some electronics, between the battery and the armature winding, and so it is possible that there will be some small amount of electrical current that will flow from the battery, through the solid-state regulator, through the armature winding, to ground.
RooDog
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Re: Panhead Wiring

#17

Post by RooDog »

I'm not talking with lead.
I am not an electrical engineer, nor do I have electronics training, but I have been involved with Harleys since 1967 and I know what works regarding the 12 V two brush generator and its idiot light, and what I have said is true.
It is the regulator's job, whether mechanical or electronic, to disengage the genny from the batt, period....
If there were any backflow through the "A" terminal when the engine was not running and the key "OFF" then that is a malfunctioning problem and needs to be rectified, or the battery will discharge while the bike is sitting parked.

Now, I'm done with this pissing contest....
....RooDog....
awander
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Re: Panhead Wiring

#18

Post by awander »

Hi, Roo:

I'm sorry if it seems like I am pissing on you-that is not my intent.

I'm just stating the facts as they apply to electrical/electronic circuits.
RooDog
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Re: Panhead Wiring

#19

Post by RooDog »

On a 12 volt generator system the regulator can be completely disconnected. It does not affect the functioning of the dash light, if you will follow this:
Disconnect the regulator completely.
leave the GEN light wire on the A terminal of the genny.
Switch on, light will be on, no?
Start engine, light will still be on.
Now, take a jumper wire from the F terminal on the genny and ground it manually. The light should go off, a volt meter on the A terminal will be high, way over 12 volts, and rise with the RPM, so do not prolong this test.

All the regulator needs to do is to electronically regulate the grounding of that field circuit, it matters not if it is mechanical or solid state.
....RooDog....
PS: It is quite likely an LED light will not function properly as an indicator, but your results may vary, as all LEDs are not created equal....
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Re: Panhead Wiring

#20

Post by awander »

Roo:

What you are missing is that in addition to regulating the Field winding current, the regulator also needs to isolate the A wining from the Battery when the output voltage of the generator is less than the battery voltage.

All electro-mechanical regulators incorporate a cutout relay for this purpose (in addition to the relay(s) for regulation of voltage (and current, if a 3-unit regulator)). The older bikes use ONLY a cutout relay, and rely on the battery itself, and the adjustment of the 3rd brush, to "regulate" the voltage/current from the generator.

A solid-state regulator needs circuitry to accomplish this connection/disconnection of the A winding to/from the Battery, but since it is not a physical set of switch contacts, there could be some small amount current flow from battery through A winding, to ground.
RooDog
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Re: Panhead Wiring

#21

Post by RooDog »

I'm not missing anything. My comments are solely directed at the GEN light.
awander
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Re: Panhead Wiring

#22

Post by awander »

Well, OK, but the OP was worried about his battery discharging, not specifically through the GEN light....
RooDog
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Re: Panhead Wiring

#23

Post by RooDog »

Batteries are known to self discharge even when not hooked to anything. Its just the nature of the best. And that is why the Harley Gods created the Battery Tender....
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